diff options
Diffstat (limited to 'arch/i386/xen')
| -rw-r--r-- | arch/i386/xen/Kconfig | 11 | ||||
| -rw-r--r-- | arch/i386/xen/Makefile | 4 | ||||
| -rw-r--r-- | arch/i386/xen/enlighten.c | 1144 | ||||
| -rw-r--r-- | arch/i386/xen/events.c | 590 | ||||
| -rw-r--r-- | arch/i386/xen/features.c | 29 | ||||
| -rw-r--r-- | arch/i386/xen/manage.c | 143 | ||||
| -rw-r--r-- | arch/i386/xen/mmu.c | 564 | ||||
| -rw-r--r-- | arch/i386/xen/mmu.h | 60 | ||||
| -rw-r--r-- | arch/i386/xen/multicalls.c | 90 | ||||
| -rw-r--r-- | arch/i386/xen/multicalls.h | 45 | ||||
| -rw-r--r-- | arch/i386/xen/setup.c | 96 | ||||
| -rw-r--r-- | arch/i386/xen/smp.c | 404 | ||||
| -rw-r--r-- | arch/i386/xen/time.c | 590 | ||||
| -rw-r--r-- | arch/i386/xen/xen-asm.S | 291 | ||||
| -rw-r--r-- | arch/i386/xen/xen-head.S | 36 | ||||
| -rw-r--r-- | arch/i386/xen/xen-ops.h | 71 |
16 files changed, 4168 insertions, 0 deletions
diff --git a/arch/i386/xen/Kconfig b/arch/i386/xen/Kconfig new file mode 100644 index 00000000000..9df99e1885a --- /dev/null +++ b/arch/i386/xen/Kconfig @@ -0,0 +1,11 @@ +# +# This Kconfig describes xen options +# + +config XEN + bool "Enable support for Xen hypervisor" + depends on PARAVIRT && X86_CMPXCHG && X86_TSC && !NEED_MULTIPLE_NODES + help + This is the Linux Xen port. Enabling this will allow the + kernel to boot in a paravirtualized environment under the + Xen hypervisor. diff --git a/arch/i386/xen/Makefile b/arch/i386/xen/Makefile new file mode 100644 index 00000000000..343df246bd3 --- /dev/null +++ b/arch/i386/xen/Makefile @@ -0,0 +1,4 @@ +obj-y := enlighten.o setup.o features.o multicalls.o mmu.o \ + events.o time.o manage.o xen-asm.o + +obj-$(CONFIG_SMP) += smp.o diff --git a/arch/i386/xen/enlighten.c b/arch/i386/xen/enlighten.c new file mode 100644 index 00000000000..9a8c1181c00 --- /dev/null +++ b/arch/i386/xen/enlighten.c @@ -0,0 +1,1144 @@ +/* + * Core of Xen paravirt_ops implementation. + * + * This file contains the xen_paravirt_ops structure itself, and the + * implementations for: + * - privileged instructions + * - interrupt flags + * - segment operations + * - booting and setup + * + * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/smp.h> +#include <linux/preempt.h> +#include <linux/hardirq.h> +#include <linux/percpu.h> +#include <linux/delay.h> +#include <linux/start_kernel.h> +#include <linux/sched.h> +#include <linux/bootmem.h> +#include <linux/module.h> +#include <linux/mm.h> +#include <linux/page-flags.h> +#include <linux/highmem.h> +#include <linux/smp.h> + +#include <xen/interface/xen.h> +#include <xen/interface/physdev.h> +#include <xen/interface/vcpu.h> +#include <xen/interface/sched.h> +#include <xen/features.h> +#include <xen/page.h> + +#include <asm/paravirt.h> +#include <asm/page.h> +#include <asm/xen/hypercall.h> +#include <asm/xen/hypervisor.h> +#include <asm/fixmap.h> +#include <asm/processor.h> +#include <asm/setup.h> +#include <asm/desc.h> +#include <asm/pgtable.h> +#include <asm/tlbflush.h> +#include <asm/reboot.h> + +#include "xen-ops.h" +#include "mmu.h" +#include "multicalls.h" + +EXPORT_SYMBOL_GPL(hypercall_page); + +DEFINE_PER_CPU(enum paravirt_lazy_mode, xen_lazy_mode); + +DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); +DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); +DEFINE_PER_CPU(unsigned long, xen_cr3); + +struct start_info *xen_start_info; +EXPORT_SYMBOL_GPL(xen_start_info); + +static /* __initdata */ struct shared_info dummy_shared_info; + +/* + * Point at some empty memory to start with. We map the real shared_info + * page as soon as fixmap is up and running. + */ +struct shared_info *HYPERVISOR_shared_info = (void *)&dummy_shared_info; + +/* + * Flag to determine whether vcpu info placement is available on all + * VCPUs. We assume it is to start with, and then set it to zero on + * the first failure. This is because it can succeed on some VCPUs + * and not others, since it can involve hypervisor memory allocation, + * or because the guest failed to guarantee all the appropriate + * constraints on all VCPUs (ie buffer can't cross a page boundary). + * + * Note that any particular CPU may be using a placed vcpu structure, + * but we can only optimise if the all are. + * + * 0: not available, 1: available + */ +static int have_vcpu_info_placement = 1; + +static void __init xen_vcpu_setup(int cpu) +{ + struct vcpu_register_vcpu_info info; + int err; + struct vcpu_info *vcpup; + + per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; + + if (!have_vcpu_info_placement) + return; /* already tested, not available */ + + vcpup = &per_cpu(xen_vcpu_info, cpu); + + info.mfn = virt_to_mfn(vcpup); + info.offset = offset_in_page(vcpup); + + printk(KERN_DEBUG "trying to map vcpu_info %d at %p, mfn %x, offset %d\n", + cpu, vcpup, info.mfn, info.offset); + + /* Check to see if the hypervisor will put the vcpu_info + structure where we want it, which allows direct access via + a percpu-variable. */ + err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info); + + if (err) { + printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err); + have_vcpu_info_placement = 0; + } else { + /* This cpu is using the registered vcpu info, even if + later ones fail to. */ + per_cpu(xen_vcpu, cpu) = vcpup; + + printk(KERN_DEBUG "cpu %d using vcpu_info at %p\n", + cpu, vcpup); + } +} + +static void __init xen_banner(void) +{ + printk(KERN_INFO "Booting paravirtualized kernel on %s\n", + paravirt_ops.name); + printk(KERN_INFO "Hypervisor signature: %s\n", xen_start_info->magic); +} + +static void xen_cpuid(unsigned int *eax, unsigned int *ebx, + unsigned int *ecx, unsigned int *edx) +{ + unsigned maskedx = ~0; + + /* + * Mask out inconvenient features, to try and disable as many + * unsupported kernel subsystems as possible. + */ + if (*eax == 1) + maskedx = ~((1 << X86_FEATURE_APIC) | /* disable APIC */ + (1 << X86_FEATURE_ACPI) | /* disable ACPI */ + (1 << X86_FEATURE_ACC)); /* thermal monitoring */ + + asm(XEN_EMULATE_PREFIX "cpuid" + : "=a" (*eax), + "=b" (*ebx), + "=c" (*ecx), + "=d" (*edx) + : "0" (*eax), "2" (*ecx)); + *edx &= maskedx; +} + +static void xen_set_debugreg(int reg, unsigned long val) +{ + HYPERVISOR_set_debugreg(reg, val); +} + +static unsigned long xen_get_debugreg(int reg) +{ + return HYPERVISOR_get_debugreg(reg); +} + +static unsigned long xen_save_fl(void) +{ + struct vcpu_info *vcpu; + unsigned long flags; + + vcpu = x86_read_percpu(xen_vcpu); + + /* flag has opposite sense of mask */ + flags = !vcpu->evtchn_upcall_mask; + + /* convert to IF type flag + -0 -> 0x00000000 + -1 -> 0xffffffff + */ + return (-flags) & X86_EFLAGS_IF; +} + +static void xen_restore_fl(unsigned long flags) +{ + struct vcpu_info *vcpu; + + /* convert from IF type flag */ + flags = !(flags & X86_EFLAGS_IF); + + /* There's a one instruction preempt window here. We need to + make sure we're don't switch CPUs between getting the vcpu + pointer and updating the mask. */ + preempt_disable(); + vcpu = x86_read_percpu(xen_vcpu); + vcpu->evtchn_upcall_mask = flags; + preempt_enable_no_resched(); + + /* Doesn't matter if we get preempted here, because any + pending event will get dealt with anyway. */ + + if (flags == 0) { + preempt_check_resched(); + barrier(); /* unmask then check (avoid races) */ + if (unlikely(vcpu->evtchn_upcall_pending)) + force_evtchn_callback(); + } +} + +static void xen_irq_disable(void) +{ + /* There's a one instruction preempt window here. We need to + make sure we're don't switch CPUs between getting the vcpu + pointer and updating the mask. */ + preempt_disable(); + x86_read_percpu(xen_vcpu)->evtchn_upcall_mask = 1; + preempt_enable_no_resched(); +} + +static void xen_irq_enable(void) +{ + struct vcpu_info *vcpu; + + /* There's a one instruction preempt window here. We need to + make sure we're don't switch CPUs between getting the vcpu + pointer and updating the mask. */ + preempt_disable(); + vcpu = x86_read_percpu(xen_vcpu); + vcpu->evtchn_upcall_mask = 0; + preempt_enable_no_resched(); + + /* Doesn't matter if we get preempted here, because any + pending event will get dealt with anyway. */ + + barrier(); /* unmask then check (avoid races) */ + if (unlikely(vcpu->evtchn_upcall_pending)) + force_evtchn_callback(); +} + +static void xen_safe_halt(void) +{ + /* Blocking includes an implicit local_irq_enable(). */ + if (HYPERVISOR_sched_op(SCHEDOP_block, 0) != 0) + BUG(); +} + +static void xen_halt(void) +{ + if (irqs_disabled()) + HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL); + else + xen_safe_halt(); +} + +static void xen_set_lazy_mode(enum paravirt_lazy_mode mode) +{ + BUG_ON(preemptible()); + + switch (mode) { + case PARAVIRT_LAZY_NONE: + BUG_ON(x86_read_percpu(xen_lazy_mode) == PARAVIRT_LAZY_NONE); + break; + + case PARAVIRT_LAZY_MMU: + case PARAVIRT_LAZY_CPU: + BUG_ON(x86_read_percpu(xen_lazy_mode) != PARAVIRT_LAZY_NONE); + break; + + case PARAVIRT_LAZY_FLUSH: + /* flush if necessary, but don't change state */ + if (x86_read_percpu(xen_lazy_mode) != PARAVIRT_LAZY_NONE) + xen_mc_flush(); + return; + } + + xen_mc_flush(); + x86_write_percpu(xen_lazy_mode, mode); +} + +static unsigned long xen_store_tr(void) +{ + return 0; +} + +static void xen_set_ldt(const void *addr, unsigned entries) +{ + unsigned long linear_addr = (unsigned long)addr; + struct mmuext_op *op; + struct multicall_space mcs = xen_mc_entry(sizeof(*op)); + + op = mcs.args; + op->cmd = MMUEXT_SET_LDT; + if (linear_addr) { + /* ldt my be vmalloced, use arbitrary_virt_to_machine */ + xmaddr_t maddr; + maddr = arbitrary_virt_to_machine((unsigned long)addr); + linear_addr = (unsigned long)maddr.maddr; + } + op->arg1.linear_addr = linear_addr; + op->arg2.nr_ents = entries; + + MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); + + xen_mc_issue(PARAVIRT_LAZY_CPU); +} + +static void xen_load_gdt(const struct Xgt_desc_struct *dtr) +{ + unsigned long *frames; + unsigned long va = dtr->address; + unsigned int size = dtr->size + 1; + unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; + int f; + struct multicall_space mcs; + + /* A GDT can be up to 64k in size, which corresponds to 8192 + 8-byte entries, or 16 4k pages.. */ + + BUG_ON(size > 65536); + BUG_ON(va & ~PAGE_MASK); + + mcs = xen_mc_entry(sizeof(*frames) * pages); + frames = mcs.args; + + for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { + frames[f] = virt_to_mfn(va); + make_lowmem_page_readonly((void *)va); + } + + MULTI_set_gdt(mcs.mc, frames, size / sizeof(struct desc_struct)); + + xen_mc_issue(PARAVIRT_LAZY_CPU); +} + +static void load_TLS_descriptor(struct thread_struct *t, + unsigned int cpu, unsigned int i) +{ + struct desc_struct *gdt = get_cpu_gdt_table(cpu); + xmaddr_t maddr = virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]); + struct multicall_space mc = __xen_mc_entry(0); + + MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]); +} + +static void xen_load_tls(struct thread_struct *t, unsigned int cpu) +{ + xen_mc_batch(); + + load_TLS_descriptor(t, cpu, 0); + load_TLS_descriptor(t, cpu, 1); + load_TLS_descriptor(t, cpu, 2); + + xen_mc_issue(PARAVIRT_LAZY_CPU); + + /* + * XXX sleazy hack: If we're being called in a lazy-cpu zone, + * it means we're in a context switch, and %gs has just been + * saved. This means we can zero it out to prevent faults on + * exit from the hypervisor if the next process has no %gs. + * Either way, it has been saved, and the new value will get + * loaded properly. This will go away as soon as Xen has been + * modified to not save/restore %gs for normal hypercalls. + */ + if (xen_get_lazy_mode() == PARAVIRT_LAZY_CPU) + loadsegment(gs, 0); +} + +static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, + u32 low, u32 high) +{ + unsigned long lp = (unsigned long)&dt[entrynum]; + xmaddr_t mach_lp = virt_to_machine(lp); + u64 entry = (u64)high << 32 | low; + + preempt_disable(); + + xen_mc_flush(); + if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry)) + BUG(); + + preempt_enable(); +} + +static int cvt_gate_to_trap(int vector, u32 low, u32 high, + struct trap_info *info) +{ + u8 type, dpl; + + type = (high >> 8) & 0x1f; + dpl = (high >> 13) & 3; + + if (type != 0xf && type != 0xe) + return 0; + + info->vector = vector; + info->address = (high & 0xffff0000) | (low & 0x0000ffff); + info->cs = low >> 16; + info->flags = dpl; + /* interrupt gates clear IF */ + if (type == 0xe) + info->flags |= 4; + + return 1; +} + +/* Locations of each CPU's IDT */ +static DEFINE_PER_CPU(struct Xgt_desc_struct, idt_desc); + +/* Set an IDT entry. If the entry is part of the current IDT, then + also update Xen. */ +static void xen_write_idt_entry(struct desc_struct *dt, int entrynum, + u32 low, u32 high) +{ + unsigned long p = (unsigned long)&dt[entrynum]; + unsigned long start, end; + + preempt_disable(); + + start = __get_cpu_var(idt_desc).address; + end = start + __get_cpu_var(idt_desc).size + 1; + + xen_mc_flush(); + + write_dt_entry(dt, entrynum, low, high); + + if (p >= start && (p + 8) <= end) { + struct trap_info info[2]; + + info[1].address = 0; + + if (cvt_gate_to_trap(entrynum, low, high, &info[0])) + if (HYPERVISOR_set_trap_table(info)) + BUG(); + } + + preempt_enable(); +} + +static void xen_convert_trap_info(const struct Xgt_desc_struct *desc, + struct trap_info *traps) +{ + unsigned in, out, count; + + count = (desc->size+1) / 8; + BUG_ON(count > 256); + + for (in = out = 0; in < count; in++) { + const u32 *entry = (u32 *)(desc->address + in * 8); + + if (cvt_gate_to_trap(in, entry[0], entry[1], &traps[out])) + out++; + } + traps[out].address = 0; +} + +void xen_copy_trap_info(struct trap_info *traps) +{ + const struct Xgt_desc_struct *desc = &__get_cpu_var(idt_desc); + + xen_convert_trap_info(desc, traps); +} + +/* Load a new IDT into Xen. In principle this can be per-CPU, so we + hold a spinlock to protect the static traps[] array (static because + it avoids allocation, and saves stack space). */ +static void xen_load_idt(const struct Xgt_desc_struct *desc) +{ + static DEFINE_SPINLOCK(lock); + static struct trap_info traps[257]; + + spin_lock(&lock); + + __get_cpu_var(idt_desc) = *desc; + + xen_convert_trap_info(desc, traps); + + xen_mc_flush(); + if (HYPERVISOR_set_trap_table(traps)) + BUG(); + + spin_unlock(&lock); +} + +/* Write a GDT descriptor entry. Ignore LDT descriptors, since + they're handled differently. */ +static void xen_write_gdt_entry(struct desc_struct *dt, int entry, + u32 low, u32 high) +{ + preempt_disable(); + + switch ((high >> 8) & 0xff) { + case DESCTYPE_LDT: + case DESCTYPE_TSS: + /* ignore */ + break; + + default: { + xmaddr_t maddr = virt_to_machine(&dt[entry]); + u64 desc = (u64)high << 32 | low; + + xen_mc_flush(); + if (HYPERVISOR_update_descriptor(maddr.maddr, desc)) + BUG(); + } + + } + + preempt_enable(); +} + +static void xen_load_esp0(struct tss_struct *tss, + struct thread_struct *thread) +{ + struct multicall_space mcs = xen_mc_entry(0); + MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->esp0); + xen_mc_issue(PARAVIRT_LAZY_CPU); +} + +static void xen_set_iopl_mask(unsigned mask) +{ + struct physdev_set_iopl set_iopl; + + /* Force the change at ring 0. */ + set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3; + HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); +} + +static void xen_io_delay(void) +{ +} + +#ifdef CONFIG_X86_LOCAL_APIC +static unsigned long xen_apic_read(unsigned long reg) +{ + return 0; +} + +static void xen_apic_write(unsigned long reg, unsigned long val) +{ + /* Warn to see if there's any stray references */ + WARN_ON(1); +} +#endif + +static void xen_flush_tlb(void) +{ + struct mmuext_op *op; + struct multicall_space mcs = xen_mc_entry(sizeof(*op)); + + op = mcs.args; + op->cmd = MMUEXT_TLB_FLUSH_LOCAL; + MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); + + xen_mc_issue(PARAVIRT_LAZY_MMU); +} + +static void xen_flush_tlb_single(unsigned long addr) +{ + struct mmuext_op *op; + struct multicall_space mcs = xen_mc_entry(sizeof(*op)); + + op = mcs.args; + op->cmd = MMUEXT_INVLPG_LOCAL; + op->arg1.linear_addr = addr & PAGE_MASK; + MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); + + xen_mc_issue(PARAVIRT_LAZY_MMU); +} + +static void xen_flush_tlb_others(const cpumask_t *cpus, struct mm_struct *mm, + unsigned long va) +{ + struct { + struct mmuext_op op; + cpumask_t mask; + } *args; + cpumask_t cpumask = *cpus; + struct multicall_space mcs; + + /* + * A couple of (to be removed) sanity checks: + * + * - current CPU must not be in mask + * - mask must exist :) + */ + BUG_ON(cpus_empty(cpumask)); + BUG_ON(cpu_isset(smp_processor_id(), cpumask)); + BUG_ON(!mm); + + /* If a CPU which we ran on has gone down, OK. */ + cpus_and(cpumask, cpumask, cpu_online_map); + if (cpus_empty(cpumask)) + return; + + mcs = xen_mc_entry(sizeof(*args)); + args = mcs.args; + args->mask = cpumask; + args->op.arg2.vcpumask = &args->mask; + + if (va == TLB_FLUSH_ALL) { + args->op.cmd = MMUEXT_TLB_FLUSH_MULTI; + } else { + args->op.cmd = MMUEXT_INVLPG_MULTI; + args->op.arg1.linear_addr = va; + } + + MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF); + + xen_mc_issue(PARAVIRT_LAZY_MMU); +} + +static void xen_write_cr2(unsigned long cr2) +{ + x86_read_percpu(xen_vcpu)->arch.cr2 = cr2; +} + +static unsigned long xen_read_cr2(void) +{ + return x86_read_percpu(xen_vcpu)->arch.cr2; +} + +static unsigned long xen_read_cr2_direct(void) +{ + return x86_read_percpu(xen_vcpu_info.arch.cr2); +} + +static void xen_write_cr4(unsigned long cr4) +{ + /* never allow TSC to be disabled */ + native_write_cr4(cr4 & ~X86_CR4_TSD); +} + +static unsigned long xen_read_cr3(void) +{ + return x86_read_percpu(xen_cr3); +} + +static void xen_write_cr3(unsigned long cr3) +{ + BUG_ON(preemptible()); + + if (cr3 == x86_read_percpu(xen_cr3)) { + /* just a simple tlb flush */ + xen_flush_tlb(); + return; + } + + x86_write_percpu(xen_cr3, cr3); + + + { + struct mmuext_op *op; + struct multicall_space mcs = xen_mc_entry(sizeof(*op)); + unsigned long mfn = pfn_to_mfn(PFN_DOWN(cr3)); + + op = mcs.args; + op->cmd = MMUEXT_NEW_BASEPTR; + op->arg1.mfn = mfn; + + MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); + + xen_mc_issue(PARAVIRT_LAZY_CPU); + } +} + +/* Early in boot, while setting up the initial pagetable, assume + everything is pinned. */ +static __init void xen_alloc_pt_init(struct mm_struct *mm, u32 pfn) +{ + BUG_ON(mem_map); /* should only be used early */ + make_lowmem_page_readonly(__va(PFN_PHYS(pfn))); +} + +/* This needs to make sure the new pte page is pinned iff its being + attached to a pinned pagetable. */ +static void xen_alloc_pt(struct mm_struct *mm, u32 pfn) +{ + struct page *page = pfn_to_page(pfn); + + if (PagePinned(virt_to_page(mm->pgd))) { + SetPagePinned(page); + + if (!PageHighMem(page)) + make_lowmem_page_readonly(__va(PFN_PHYS(pfn))); + else + /* make sure there are no stray mappings of + this page */ + kmap_flush_unused(); + } +} + +/* This should never happen until we're OK to use struct page */ +static void xen_release_pt(u32 pfn) +{ + struct page *page = pfn_to_page(pfn); + + if (PagePinned(page)) { + if (!PageHighMem(page)) + make_lowmem_page_readwrite(__va(PFN_PHYS(pfn))); + } +} + +#ifdef CONFIG_HIGHPTE +static void *xen_kmap_atomic_pte(struct page *page, enum km_type type) +{ + pgprot_t prot = PAGE_KERNEL; + + if (PagePinned(page)) + prot = PAGE_KERNEL_RO; + + if (0 && PageHighMem(page)) + printk("mapping highpte %lx type %d prot %s\n", + page_to_pfn(page), type, + (unsigned long)pgprot_val(prot) & _PAGE_RW ? "WRITE" : "READ"); + + return kmap_atomic_prot(page, type, prot); +} +#endif + +static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte) +{ + /* If there's an existing pte, then don't allow _PAGE_RW to be set */ + if (pte_val_ma(*ptep) & _PAGE_PRESENT) + pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) & + pte_val_ma(pte)); + + return pte; +} + +/* Init-time set_pte while constructing initial pagetables, which + doesn't allow RO pagetable pages to be remapped RW */ +static __init void xen_set_pte_init(pte_t *ptep, pte_t pte) +{ + pte = mask_rw_pte(ptep, pte); + + xen_set_pte(ptep, pte); +} + +static __init void xen_pagetable_setup_start(pgd_t *base) +{ + pgd_t *xen_pgd = (pgd_t *)xen_start_info->pt_base; + + /* special set_pte for pagetable initialization */ + paravirt_ops.set_pte = xen_set_pte_init; + + init_mm.pgd = base; + /* + * copy top-level of Xen-supplied pagetable into place. For + * !PAE we can use this as-is, but for PAE it is a stand-in + * while we copy the pmd pages. + */ + memcpy(base, xen_pgd, PTRS_PER_PGD * sizeof(pgd_t)); + + if (PTRS_PER_PMD > 1) { + int i; + /* + * For PAE, need to allocate new pmds, rather than + * share Xen's, since Xen doesn't like pmd's being + * shared between address spaces. + */ + for (i = 0; i < PTRS_PER_PGD; i++) { + if (pgd_val_ma(xen_pgd[i]) & _PAGE_PRESENT) { + pmd_t *pmd = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE); + + memcpy(pmd, (void *)pgd_page_vaddr(xen_pgd[i]), + PAGE_SIZE); + + make_lowmem_page_readonly(pmd); + + set_pgd(&base[i], __pgd(1 + __pa(pmd))); + } else + pgd_clear(&base[i]); + } + } + + /* make sure zero_page is mapped RO so we can use it in pagetables */ + make_lowmem_page_readonly(empty_zero_page); + make_lowmem_page_readonly(base); + /* + * Switch to new pagetable. This is done before + * pagetable_init has done anything so that the new pages + * added to the table can be prepared properly for Xen. + */ + xen_write_cr3(__pa(base)); +} + +static __init void xen_pagetable_setup_done(pgd_t *base) +{ + /* This will work as long as patching hasn't happened yet + (which it hasn't) */ + paravirt_ops.alloc_pt = xen_alloc_pt; + paravirt_ops.set_pte = xen_set_pte; + + if (!xen_feature(XENFEAT_auto_translated_physmap)) { + /* + * Create a mapping for the shared info page. + * Should be set_fixmap(), but shared_info is a machine + * address with no corresponding pseudo-phys address. + */ + set_pte_mfn(fix_to_virt(FIX_PARAVIRT_BOOTMAP), + PFN_DOWN(xen_start_info->shared_info), + PAGE_KERNEL); + + HYPERVISOR_shared_info = + (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP); + + } else + HYPERVISOR_shared_info = + (struct shared_info *)__va(xen_start_info->shared_info); + + /* Actually pin the pagetable down, but we can't set PG_pinned + yet because the page structures don't exist yet. */ + { + struct mmuext_op op; +#ifdef CONFIG_X86_PAE + op.cmd = MMUEXT_PIN_L3_TABLE; +#else + op.cmd = MMUEXT_PIN_L3_TABLE; +#endif + op.arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(base))); + if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF)) + BUG(); + } +} + +/* This is called once we have the cpu_possible_map */ +void __init xen_setup_vcpu_info_placement(void) +{ + int cpu; + + for_each_possible_cpu(cpu) + xen_vcpu_setup(cpu); + + /* xen_vcpu_setup managed to place the vcpu_info within the + percpu area for all cpus, so make use of it */ + if (have_vcpu_info_placement) { + printk(KERN_INFO "Xen: using vcpu_info placement\n"); + + paravirt_ops.save_fl = xen_save_fl_direct; + paravirt_ops.restore_fl = xen_restore_fl_direct; + paravirt_ops.irq_disable = xen_irq_disable_direct; + paravirt_ops.irq_enable = xen_irq_enable_direct; + paravirt_ops.read_cr2 = xen_read_cr2_direct; + paravirt_ops.iret = xen_iret_direct; + } +} + +static unsigned xen_patch(u8 type, u16 clobbers, void *insns, unsigned len) +{ + char *start, *end, *reloc; + unsigned ret; + + start = end = reloc = NULL; + +#define SITE(x) \ + case PARAVIRT_PATCH(x): \ + if (have_vcpu_info_placement) { \ + start = (char *)xen_##x##_direct; \ + end = xen_##x##_direct_end; \ + reloc = xen_##x##_direct_reloc; \ + } \ + goto patch_site + + switch (type) { + SITE(irq_enable); + SITE(irq_disable); + SITE(save_fl); + SITE(restore_fl); +#undef SITE + + patch_site: + if (start == NULL || (end-start) > len) + goto default_patch; + + ret = paravirt_patch_insns(insns, len, start, end); + + /* Note: because reloc is assigned from something that + appears to be an array, gcc assumes it's non-null, + but doesn't know its relationship with start and + end. */ + if (reloc > start && reloc < end) { + int reloc_off = reloc - start; + long *relocp = (long *)(insns + reloc_off); + long delta = start - (char *)insns; + + *relocp += delta; + } + break; + + default_patch: + default: + ret = paravirt_patch_default(type, clobbers, insns, len); + break; + } + + return ret; +} + +static const struct paravirt_ops xen_paravirt_ops __initdata = { + .paravirt_enabled = 1, + .shared_kernel_pmd = 0, + + .name = "Xen", + .banner = xen_banner, + + .patch = xen_patch, + + .memory_setup = xen_memory_setup, + .arch_setup = xen_arch_setup, + .init_IRQ = xen_init_IRQ, + .post_allocator_init = xen_mark_init_mm_pinned, + + .time_init = xen_time_init, + .set_wallclock = xen_set_wallclock, + .get_wallclock = xen_get_wallclock, + .get_cpu_khz = xen_cpu_khz, + .sched_clock = xen_sched_clock, + + .cpuid = xen_cpuid, + + .set_debugreg = xen_set_debugreg, + .get_debugreg = xen_get_debugreg, + + .clts = native_clts, + + .read_cr0 = native_read_cr0, + .write_cr0 = native_write_cr0, + + .read_cr2 = xen_read_cr2, + .write_cr2 = xen_write_cr2, + + .read_cr3 = xen_read_cr3, + .write_cr3 = xen_write_cr3, + + .read_cr4 = native_read_cr4, + .read_cr4_safe = native_read_cr4_safe, + .write_cr4 = xen_write_cr4, + + .save_fl = xen_save_fl, + .restore_fl = xen_restore_fl, + .irq_disable = xen_irq_disable, + .irq_enable = xen_irq_enable, + .safe_halt = xen_safe_halt, + .halt = xen_halt, + .wbinvd = native_wbinvd, + + .read_msr = native_read_msr_safe, + .write_msr = native_write_msr_safe, + .read_tsc = native_read_tsc, + .read_pmc = native_read_pmc, + + .iret = (void *)&hypercall_page[__HYPERVISOR_iret], + .irq_enable_sysexit = NULL, /* never called */ + + .load_tr_desc = paravirt_nop, + .set_ldt = xen_set_ldt, + .load_gdt = xen_load_gdt, + .load_idt = xen_load_idt, + .load_tls = xen_load_tls, + + .store_gdt = native_store_gdt, + .store_idt = native_store_idt, + .store_tr = xen_store_tr, + + .write_ldt_entry = xen_write_ldt_entry, + .write_gdt_entry = xen_write_gdt_entry, + .write_idt_entry = xen_write_idt_entry, + .load_esp0 = xen_load_esp0, + + .set_iopl_mask = xen_set_iopl_mask, + .io_delay = xen_io_delay, + +#ifdef CONFIG_X86_LOCAL_APIC + .apic_write = xen_apic_write, + .apic_write_atomic = xen_apic_write, + .apic_read = xen_apic_read, + .setup_boot_clock = paravirt_nop, + .setup_secondary_clock = paravirt_nop, + .startup_ipi_hook = paravirt_nop, +#endif + + .flush_tlb_user = xen_flush_tlb, + .flush_tlb_kernel = xen_flush_tlb, + .flush_tlb_single = xen_flush_tlb_single, + .flush_tlb_others = xen_flush_tlb_others, + + .pte_update = paravirt_nop, + .pte_update_defer = paravirt_nop, + + .pagetable_setup_start = xen_pagetable_setup_start, + .pagetable_setup_done = xen_pagetable_setup_done, + + .alloc_pt = xen_alloc_pt_init, + .release_pt = xen_release_pt, + .alloc_pd = paravirt_nop, + .alloc_pd_clone = paravirt_nop, + .release_pd = paravirt_nop, + +#ifdef CONFIG_HIGHPTE + .kmap_atomic_pte = xen_kmap_atomic_pte, +#endif + + .set_pte = NULL, /* see xen_pagetable_setup_* */ + .set_pte_at = xen_set_pte_at, + .set_pmd = xen_set_pmd, + + .pte_val = xen_pte_val, + .pgd_val = xen_pgd_val, + + .make_pte = xen_make_pte, + .make_pgd = xen_make_pgd, + +#ifdef CONFIG_X86_PAE + .set_pte_atomic = xen_set_pte_atomic, + .set_pte_present = xen_set_pte_at, + .set_pud = xen_set_pud, + .pte_clear = xen_pte_clear, + .pmd_clear = xen_pmd_clear, + + .make_pmd = xen_make_pmd, + .pmd_val = xen_pmd_val, +#endif /* PAE */ + + .activate_mm = xen_activate_mm, + .dup_mmap = xen_dup_mmap, + .exit_mmap = xen_exit_mmap, + + .set_lazy_mode = xen_set_lazy_mode, +}; + +#ifdef CONFIG_SMP +static const struct smp_ops xen_smp_ops __initdata = { + .smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu, + .smp_prepare_cpus = xen_smp_prepare_cpus, + .cpu_up = xen_cpu_up, + .smp_cpus_done = xen_smp_cpus_done, + + .smp_send_stop = xen_smp_send_stop, + .smp_send_reschedule = xen_smp_send_reschedule, + .smp_call_function_mask = xen_smp_call_function_mask, +}; +#endif /* CONFIG_SMP */ + +static void xen_reboot(int reason) +{ +#ifdef CONFIG_SMP + smp_send_stop(); +#endif + + if (HYPERVISOR_sched_op(SCHEDOP_shutdown, reason)) + BUG(); +} + +static void xen_restart(char *msg) +{ + xen_reboot(SHUTDOWN_reboot); +} + +static void xen_emergency_restart(void) +{ + xen_reboot(SHUTDOWN_reboot); +} + +static void xen_machine_halt(void) +{ + xen_reboot(SHUTDOWN_poweroff); +} + +static void xen_crash_shutdown(struct pt_regs *regs) +{ + xen_reboot(SHUTDOWN_crash); +} + +static const struct machine_ops __initdata xen_machine_ops = { + .restart = xen_restart, + .halt = xen_machine_halt, + .power_off = xen_machine_halt, + .shutdown = xen_machine_halt, + .crash_shutdown = xen_crash_shutdown, + .emergency_restart = xen_emergency_restart, +}; + + +/* First C function to be called on Xen boot */ +asmlinkage void __init xen_start_kernel(void) +{ + pgd_t *pgd; + + if (!xen_start_info) + return; + + BUG_ON(memcmp(xen_start_info->magic, "xen-3.0", 7) != 0); + + /* Install Xen paravirt ops */ + paravirt_ops = xen_paravirt_ops; + machine_ops = xen_machine_ops; + +#ifdef CONFIG_SMP + smp_ops = xen_smp_ops; +#endif + + xen_setup_features(); + + /* Get mfn list */ + if (!xen_feature(XENFEAT_auto_translated_physmap)) + phys_to_machine_mapping = (unsigned long *)xen_start_info->mfn_list; + + pgd = (pgd_t *)xen_start_info->pt_base; + + init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE; + + init_mm.pgd = pgd; /* use the Xen pagetables to start */ + + /* keep using Xen gdt for now; no urgent need to change it */ + + x86_write_percpu(xen_cr3, __pa(pgd)); + +#ifdef CONFIG_SMP + /* Don't do the full vcpu_info placement stuff until we have a + possible map. */ + per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; +#else + /* May as well do it now, since there's no good time to call + it later on UP. */ + xen_setup_vcpu_info_placement(); +#endif + + paravirt_ops.kernel_rpl = 1; + if (xen_feature(XENFEAT_supervisor_mode_kernel)) + paravirt_ops.kernel_rpl = 0; + + /* set the limit of our address space */ + reserve_top_address(-HYPERVISOR_VIRT_START + 2 * PAGE_SIZE); + + /* set up basic CPUID stuff */ + cpu_detect(&new_cpu_data); + new_cpu_data.hard_math = 1; + new_cpu_data.x86_capability[0] = cpuid_edx(1); + + /* Poke various useful things into boot_params */ + LOADER_TYPE = (9 << 4) | 0; + INITRD_START = xen_start_info->mod_start ? __pa(xen_start_info->mod_start) : 0; + INITRD_SIZE = xen_start_info->mod_len; + + /* Start the world */ + start_kernel(); +} diff --git a/arch/i386/xen/events.c b/arch/i386/xen/events.c new file mode 100644 index 00000000000..8904acc20f8 --- /dev/null +++ b/arch/i386/xen/events.c @@ -0,0 +1,590 @@ +/* + * Xen event channels + * + * Xen models interrupts with abstract event channels. Because each + * domain gets 1024 event channels, but NR_IRQ is not that large, we + * must dynamically map irqs<->event channels. The event channels + * interface with the rest of the kernel by defining a xen interrupt + * chip. When an event is recieved, it is mapped to an irq and sent + * through the normal interrupt processing path. + * + * There are four kinds of events which can be mapped to an event + * channel: + * + * 1. Inter-domain notifications. This includes all the virtual + * device events, since they're driven by front-ends in another domain + * (typically dom0). + * 2. VIRQs, typically used for timers. These are per-cpu events. + * 3. IPIs. + * 4. Hardware interrupts. Not supported at present. + * + * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 + */ + +#include <linux/linkage.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/module.h> +#include <linux/string.h> + +#include <asm/ptrace.h> +#include <asm/irq.h> +#include <asm/sync_bitops.h> +#include <asm/xen/hypercall.h> + +#include <xen/events.h> +#include <xen/interface/xen.h> +#include <xen/interface/event_channel.h> + +#include "xen-ops.h" + +/* + * This lock protects updates to the following mapping and reference-count + * arrays. The lock does not need to be acquired to read the mapping tables. + */ +static DEFINE_SPINLOCK(irq_mapping_update_lock); + +/* IRQ <-> VIRQ mapping. */ +static DEFINE_PER_CPU(int, virq_to_irq[NR_VIRQS]) = {[0 ... NR_VIRQS-1] = -1}; + +/* IRQ <-> IPI mapping */ +static DEFINE_PER_CPU(int, ipi_to_irq[XEN_NR_IPIS]) = {[0 ... XEN_NR_IPIS-1] = -1}; + +/* Packed IRQ information: binding type, sub-type index, and event channel. */ +struct packed_irq +{ + unsigned short evtchn; + unsigned char index; + unsigned char type; +}; + +static struct packed_irq irq_info[NR_IRQS]; + +/* Binding types. */ +enum { + IRQT_UNBOUND, + IRQT_PIRQ, + IRQT_VIRQ, + IRQT_IPI, + IRQT_EVTCHN +}; + +/* Convenient shorthand for packed representation of an unbound IRQ. */ +#define IRQ_UNBOUND mk_irq_info(IRQT_UNBOUND, 0, 0) + +static int evtchn_to_irq[NR_EVENT_CHANNELS] = { + [0 ... NR_EVENT_CHANNELS-1] = -1 +}; +static unsigned long cpu_evtchn_mask[NR_CPUS][NR_EVENT_CHANNELS/BITS_PER_LONG]; +static u8 cpu_evtchn[NR_EVENT_CHANNELS]; + +/* Reference counts for bindings to IRQs. */ +static int irq_bindcount[NR_IRQS]; + +/* Xen will never allocate port zero for any purpose. */ +#define VALID_EVTCHN(chn) ((chn) != 0) + +/* + * Force a proper event-channel callback from Xen after clearing the + * callback mask. We do this in a very simple manner, by making a call + * down into Xen. The pending flag will be checked by Xen on return. + */ +void force_evtchn_callback(void) +{ + (void)HYPERVISOR_xen_version(0, NULL); +} +EXPORT_SYMBOL_GPL(force_evtchn_callback); + +static struct irq_chip xen_dynamic_chip; + +/* Constructor for packed IRQ information. */ +static inline struct packed_irq mk_irq_info(u32 type, u32 index, u32 evtchn) +{ + return (struct packed_irq) { evtchn, index, type }; +} + +/* + * Accessors for packed IRQ information. + */ +static inline unsigned int evtchn_from_irq(int irq) +{ + return irq_info[irq].evtchn; +} + +static inline unsigned int index_from_irq(int irq) +{ + return irq_info[irq].index; +} + +static inline unsigned int type_from_irq(int irq) +{ + return irq_info[irq].type; +} + +static inline unsigned long active_evtchns(unsigned int cpu, + struct shared_info *sh, + unsigned int idx) +{ + return (sh->evtchn_pending[idx] & + cpu_evtchn_mask[cpu][idx] & + ~sh->evtchn_mask[idx]); +} + +static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu) +{ + int irq = evtchn_to_irq[chn]; + + BUG_ON(irq == -1); +#ifdef CONFIG_SMP + irq_desc[irq].affinity = cpumask_of_cpu(cpu); +#endif + + __clear_bit(chn, cpu_evtchn_mask[cpu_evtchn[chn]]); + __set_bit(chn, cpu_evtchn_mask[cpu]); + + cpu_evtchn[chn] = cpu; +} + +static void init_evtchn_cpu_bindings(void) +{ +#ifdef CONFIG_SMP + int i; + /* By default all event channels notify CPU#0. */ + for (i = 0; i < NR_IRQS; i++) + irq_desc[i].affinity = cpumask_of_cpu(0); +#endif + + memset(cpu_evtchn, 0, sizeof(cpu_evtchn)); + memset(cpu_evtchn_mask[0], ~0, sizeof(cpu_evtchn_mask[0])); +} + +static inline unsigned int cpu_from_evtchn(unsigned int evtchn) +{ + return cpu_evtchn[evtchn]; +} + +static inline void clear_evtchn(int port) +{ + struct shared_info *s = HYPERVISOR_shared_info; + sync_clear_bit(port, &s->evtchn_pending[0]); +} + +static inline void set_evtchn(int port) +{ + struct shared_info *s = HYPERVISOR_shared_info; + sync_set_bit(port, &s->evtchn_pending[0]); +} + + +/** + * notify_remote_via_irq - send event to remote end of event channel via irq + * @irq: irq of event channel to send event to + * + * Unlike notify_remote_via_evtchn(), this is safe to use across + * save/restore. Notifications on a broken connection are silently + * dropped. + */ +void notify_remote_via_irq(int irq) +{ + int evtchn = evtchn_from_irq(irq); + + if (VALID_EVTCHN(evtchn)) + notify_remote_via_evtchn(evtchn); +} +EXPORT_SYMBOL_GPL(notify_remote_via_irq); + +static void mask_evtchn(int port) +{ + struct shared_info *s = HYPERVISOR_shared_info; + sync_set_bit(port, &s->evtchn_mask[0]); +} + +static void unmask_evtchn(int port) +{ + struct shared_info *s = HYPERVISOR_shared_info; + unsigned int cpu = get_cpu(); + + BUG_ON(!irqs_disabled()); + + /* Slow path (hypercall) if this is a non-local port. */ + if (unlikely(cpu != cpu_from_evtchn(port))) { + struct evtchn_unmask unmask = { .port = port }; + (void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask); + } else { + struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu); + + sync_clear_bit(port, &s->evtchn_mask[0]); + + /* + * The following is basically the equivalent of + * 'hw_resend_irq'. Just like a real IO-APIC we 'lose + * the interrupt edge' if the channel is masked. + */ + if (sync_test_bit(port, &s->evtchn_pending[0]) && + !sync_test_and_set_bit(port / BITS_PER_LONG, + &vcpu_info->evtchn_pending_sel)) + vcpu_info->evtchn_upcall_pending = 1; + } + + put_cpu(); +} + +static int find_unbound_irq(void) +{ + int irq; + + /* Only allocate from dynirq range */ + for (irq = 0; irq < NR_IRQS; irq++) + if (irq_bindcount[irq] == 0) + break; + + if (irq == NR_IRQS) + panic("No available IRQ to bind to: increase NR_IRQS!\n"); + + return irq; +} + +int bind_evtchn_to_irq(unsigned int evtchn) +{ + int irq; + + spin_lock(&irq_mapping_update_lock); + + irq = evtchn_to_irq[evtchn]; + + if (irq == -1) { + irq = find_unbound_irq(); + + dynamic_irq_init(irq); + set_irq_chip_and_handler_name(irq, &xen_dynamic_chip, + handle_level_irq, "event"); + + evtchn_to_irq[evtchn] = irq; + irq_info[irq] = mk_irq_info(IRQT_EVTCHN, 0, evtchn); + } + + irq_bindcount[irq]++; + + spin_unlock(&irq_mapping_update_lock); + + return irq; +} +EXPORT_SYMBOL_GPL(bind_evtchn_to_irq); + +static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu) +{ + struct evtchn_bind_ipi bind_ipi; + int evtchn, irq; + + spin_lock(&irq_mapping_update_lock); + + irq = per_cpu(ipi_to_irq, cpu)[ipi]; + if (irq == -1) { + irq = find_unbound_irq(); + if (irq < 0) + goto out; + + dynamic_irq_init(irq); + set_irq_chip_and_handler_name(irq, &xen_dynamic_chip, + handle_level_irq, "ipi"); + + bind_ipi.vcpu = cpu; + if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi, + &bind_ipi) != 0) + BUG(); + evtchn = bind_ipi.port; + + evtchn_to_irq[evtchn] = irq; + irq_info[irq] = mk_irq_info(IRQT_IPI, ipi, evtchn); + + per_cpu(ipi_to_irq, cpu)[ipi] = irq; + + bind_evtchn_to_cpu(evtchn, cpu); + } + + irq_bindcount[irq]++; + + out: + spin_unlock(&irq_mapping_update_lock); + return irq; +} + + +static int bind_virq_to_irq(unsigned int virq, unsigned int cpu) +{ + struct evtchn_bind_virq bind_virq; + int evtchn, irq; + + spin_lock(&irq_mapping_update_lock); + + irq = per_cpu(virq_to_irq, cpu)[virq]; + + if (irq == -1) { + bind_virq.virq = virq; + bind_virq.vcpu = cpu; + if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq, + &bind_virq) != 0) + BUG(); + evtchn = bind_virq.port; + + irq = find_unbound_irq(); + + dynamic_irq_init(irq); + set_irq_chip_and_handler_name(irq, &xen_dynamic_chip, + handle_level_irq, "virq"); + + evtchn_to_irq[evtchn] = irq; + irq_info[irq] = mk_irq_info(IRQT_VIRQ, virq, evtchn); + + per_cpu(virq_to_irq, cpu)[virq] = irq; + + bind_evtchn_to_cpu(evtchn, cpu); + } + + irq_bindcount[irq]++; + + spin_unlock(&irq_mapping_update_lock); + + return irq; +} + +static void unbind_from_irq(unsigned int irq) +{ + struct evtchn_close close; + int evtchn = evtchn_from_irq(irq); + + spin_lock(&irq_mapping_update_lock); + + if (VALID_EVTCHN(evtchn) && (--irq_bindcount[irq] == 0)) { + close.port = evtchn; + if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0) + BUG(); + + switch (type_from_irq(irq)) { + case IRQT_VIRQ: + per_cpu(virq_to_irq, cpu_from_evtchn(evtchn)) + [index_from_irq(irq)] = -1; + break; + default: + break; + } + + /* Closed ports are implicitly re-bound to VCPU0. */ + bind_evtchn_to_cpu(evtchn, 0); + + evtchn_to_irq[evtchn] = -1; + irq_info[irq] = IRQ_UNBOUND; + + dynamic_irq_init(irq); + } + + spin_unlock(&irq_mapping_update_lock); +} + +int bind_evtchn_to_irqhandler(unsigned int evtchn, + irqreturn_t (*handler)(int, void *), + unsigned long irqflags, + const char *devname, void *dev_id) +{ + unsigned int irq; + int retval; + + irq = bind_evtchn_to_irq(evtchn); + retval = request_irq(irq, handler, irqflags, devname, dev_id); + if (retval != 0) { + unbind_from_irq(irq); + return retval; + } + + return irq; +} +EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler); + +int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu, + irqreturn_t (*handler)(int, void *), + unsigned long irqflags, const char *devname, void *dev_id) +{ + unsigned int irq; + int retval; + + irq = bind_virq_to_irq(virq, cpu); + retval = request_irq(irq, handler, irqflags, devname, dev_id); + if (retval != 0) { + unbind_from_irq(irq); + return retval; + } + + return irq; +} +EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler); + +int bind_ipi_to_irqhandler(enum ipi_vector ipi, + unsigned int cpu, + irq_handler_t handler, + unsigned long irqflags, + const char *devname, + void *dev_id) +{ + int irq, retval; + + irq = bind_ipi_to_irq(ipi, cpu); + if (irq < 0) + return irq; + + retval = request_irq(irq, handler, irqflags, devname, dev_id); + if (retval != 0) { + unbind_from_irq(irq); + return retval; + } + + return irq; +} + +void unbind_from_irqhandler(unsigned int irq, void *dev_id) +{ + free_irq(irq, dev_id); + unbind_from_irq(irq); +} +EXPORT_SYMBOL_GPL(unbind_from_irqhandler); + +void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector) +{ + int irq = per_cpu(ipi_to_irq, cpu)[vector]; + BUG_ON(irq < 0); + notify_remote_via_irq(irq); +} + + +/* + * Search the CPUs pending events bitmasks. For each one found, map + * the event number to an irq, and feed it into do_IRQ() for + * handling. + * + * Xen uses a two-level bitmap to speed searching. The first level is + * a bitset of words which contain pending event bits. The second + * level is a bitset of pending events themselves. + */ +fastcall void xen_evtchn_do_upcall(struct pt_regs *regs) +{ + int cpu = get_cpu(); + struct shared_info *s = HYPERVISOR_shared_info; + struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu); + unsigned long pending_words; + + vcpu_info->evtchn_upcall_pending = 0; + + /* NB. No need for a barrier here -- XCHG is a barrier on x86. */ + pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0); + while (pending_words != 0) { + unsigned long pending_bits; + int word_idx = __ffs(pending_words); + pending_words &= ~(1UL << word_idx); + + while ((pending_bits = active_evtchns(cpu, s, word_idx)) != 0) { + int bit_idx = __ffs(pending_bits); + int port = (word_idx * BITS_PER_LONG) + bit_idx; + int irq = evtchn_to_irq[port]; + + if (irq != -1) { + regs->orig_eax = ~irq; + do_IRQ(regs); + } + } + } + + put_cpu(); +} + +/* Rebind an evtchn so that it gets delivered to a specific cpu */ +static void rebind_irq_to_cpu(unsigned irq, unsigned tcpu) +{ + struct evtchn_bind_vcpu bind_vcpu; + int evtchn = evtchn_from_irq(irq); + + if (!VALID_EVTCHN(evtchn)) + return; + + /* Send future instances of this interrupt to other vcpu. */ + bind_vcpu.port = evtchn; + bind_vcpu.vcpu = tcpu; + + /* + * If this fails, it usually just indicates that we're dealing with a + * virq or IPI channel, which don't actually need to be rebound. Ignore + * it, but don't do the xenlinux-level rebind in that case. + */ + if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0) + bind_evtchn_to_cpu(evtchn, tcpu); +} + + +static void set_affinity_irq(unsigned irq, cpumask_t dest) +{ + unsigned tcpu = first_cpu(dest); + rebind_irq_to_cpu(irq, tcpu); +} + +static void enable_dynirq(unsigned int irq) +{ + int evtchn = evtchn_from_irq(irq); + + if (VALID_EVTCHN(evtchn)) + unmask_evtchn(evtchn); +} + +static void disable_dynirq(unsigned int irq) +{ + int evtchn = evtchn_from_irq(irq); + + if (VALID_EVTCHN(evtchn)) + mask_evtchn(evtchn); +} + +static void ack_dynirq(unsigned int irq) +{ + int evtchn = evtchn_from_irq(irq); + + move_native_irq(irq); + + if (VALID_EVTCHN(evtchn)) + clear_evtchn(evtchn); +} + +static int retrigger_dynirq(unsigned int irq) +{ + int evtchn = evtchn_from_irq(irq); + int ret = 0; + + if (VALID_EVTCHN(evtchn)) { + set_evtchn(evtchn); + ret = 1; + } + + return ret; +} + +static struct irq_chip xen_dynamic_chip __read_mostly = { + .name = "xen-dyn", + .mask = disable_dynirq, + .unmask = enable_dynirq, + .ack = ack_dynirq, + .set_affinity = set_affinity_irq, + .retrigger = retrigger_dynirq, +}; + +void __init xen_init_IRQ(void) +{ + int i; + + init_evtchn_cpu_bindings(); + + /* No event channels are 'live' right now. */ + for (i = 0; i < NR_EVENT_CHANNELS; i++) + mask_evtchn(i); + + /* Dynamic IRQ space is currently unbound. Zero the refcnts. */ + for (i = 0; i < NR_IRQS; i++) + irq_bindcount[i] = 0; + + irq_ctx_init(smp_processor_id()); +} diff --git a/arch/i386/xen/features.c b/arch/i386/xen/features.c new file mode 100644 index 00000000000..0707714e40d --- /dev/null +++ b/arch/i386/xen/features.c @@ -0,0 +1,29 @@ +/****************************************************************************** + * features.c + * + * Xen feature flags. + * + * Copyright (c) 2006, Ian Campbell, XenSource Inc. + */ +#include <linux/types.h> +#include <linux/cache.h> +#include <linux/module.h> +#include <asm/xen/hypervisor.h> +#include <xen/features.h> + +u8 xen_features[XENFEAT_NR_SUBMAPS * 32] __read_mostly; +EXPORT_SYMBOL_GPL(xen_features); + +void xen_setup_features(void) +{ + struct xen_feature_info fi; + int i, j; + + for (i = 0; i < XENFEAT_NR_SUBMAPS; i++) { + fi.submap_idx = i; + if (HYPERVISOR_xen_version(XENVER_get_features, &fi) < 0) + break; + for (j = 0; j < 32; j++) + xen_features[i * 32 + j] = !!(fi.submap & 1<<j); + } +} diff --git a/arch/i386/xen/manage.c b/arch/i386/xen/manage.c new file mode 100644 index 00000000000..aa7af9e6abc --- /dev/null +++ b/arch/i386/xen/manage.c @@ -0,0 +1,143 @@ +/* + * Handle extern requests for shutdown, reboot and sysrq + */ +#include <linux/kernel.h> +#include <linux/err.h> +#include <linux/reboot.h> +#include <linux/sysrq.h> + +#include <xen/xenbus.h> + +#define SHUTDOWN_INVALID -1 +#define SHUTDOWN_POWEROFF 0 +#define SHUTDOWN_SUSPEND 2 +/* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only + * report a crash, not be instructed to crash! + * HALT is the same as POWEROFF, as far as we're concerned. The tools use + * the distinction when we return the reason code to them. + */ +#define SHUTDOWN_HALT 4 + +/* Ignore multiple shutdown requests. */ +static int shutting_down = SHUTDOWN_INVALID; + +static void shutdown_handler(struct xenbus_watch *watch, + const char **vec, unsigned int len) +{ + char *str; + struct xenbus_transaction xbt; + int err; + + if (shutting_down != SHUTDOWN_INVALID) + return; + + again: + err = xenbus_transaction_start(&xbt); + if (err) + return; + + str = (char *)xenbus_read(xbt, "control", "shutdown", NULL); + /* Ignore read errors and empty reads. */ + if (XENBUS_IS_ERR_READ(str)) { + xenbus_transaction_end(xbt, 1); + return; + } + + xenbus_write(xbt, "control", "shutdown", ""); + + err = xenbus_transaction_end(xbt, 0); + if (err == -EAGAIN) { + kfree(str); + goto again; + } + + if (strcmp(str, "poweroff") == 0 || + strcmp(str, "halt") == 0) + orderly_poweroff(false); + else if (strcmp(str, "reboot") == 0) + ctrl_alt_del(); + else { + printk(KERN_INFO "Ignoring shutdown request: %s\n", str); + shutting_down = SHUTDOWN_INVALID; + } + + kfree(str); +} + +static void sysrq_handler(struct xenbus_watch *watch, const char **vec, + unsigned int len) +{ + char sysrq_key = '\0'; + struct xenbus_transaction xbt; + int err; + + again: + err = xenbus_transaction_start(&xbt); + if (err) + return; + if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) { + printk(KERN_ERR "Unable to read sysrq code in " + "control/sysrq\n"); + xenbus_transaction_end(xbt, 1); + return; + } + + if (sysrq_key != '\0') + xenbus_printf(xbt, "control", "sysrq", "%c", '\0'); + + err = xenbus_transaction_end(xbt, 0); + if (err == -EAGAIN) + goto again; + + if (sysrq_key != '\0') + handle_sysrq(sysrq_key, NULL); +} + +static struct xenbus_watch shutdown_watch = { + .node = "control/shutdown", + .callback = shutdown_handler +}; + +static struct xenbus_watch sysrq_watch = { + .node = "control/sysrq", + .callback = sysrq_handler +}; + +static int setup_shutdown_watcher(void) +{ + int err; + + err = register_xenbus_watch(&shutdown_watch); + if (err) { + printk(KERN_ERR "Failed to set shutdown watcher\n"); + return err; + } + + err = register_xenbus_watch(&sysrq_watch); + if (err) { + printk(KERN_ERR "Failed to set sysrq watcher\n"); + return err; + } + + return 0; +} + +static int shutdown_event(struct notifier_block *notifier, + unsigned long event, + void *data) +{ + setup_shutdown_watcher(); + return NOTIFY_DONE; +} + +static int __init setup_shutdown_event(void) +{ + static struct notifier_block xenstore_notifier = { + .notifier_call = shutdown_event + }; + register_xenstore_notifier(&xenstore_notifier); + + return 0; +} + +subsys_initcall(setup_shutdown_event); diff --git a/arch/i386/xen/mmu.c b/arch/i386/xen/mmu.c new file mode 100644 index 00000000000..4ae038aa6c2 --- /dev/null +++ b/arch/i386/xen/mmu.c @@ -0,0 +1,564 @@ +/* + * Xen mmu operations + * + * This file contains the various mmu fetch and update operations. + * The most important job they must perform is the mapping between the + * domain's pfn and the overall machine mfns. + * + * Xen allows guests to directly update the pagetable, in a controlled + * fashion. In other words, the guest modifies the same pagetable + * that the CPU actually uses, which eliminates the overhead of having + * a separate shadow pagetable. + * + * In order to allow this, it falls on the guest domain to map its + * notion of a "physical" pfn - which is just a domain-local linear + * address - into a real "machine address" which the CPU's MMU can + * use. + * + * A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be + * inserted directly into the pagetable. When creating a new + * pte/pmd/pgd, it converts the passed pfn into an mfn. Conversely, + * when reading the content back with __(pgd|pmd|pte)_val, it converts + * the mfn back into a pfn. + * + * The other constraint is that all pages which make up a pagetable + * must be mapped read-only in the guest. This prevents uncontrolled + * guest updates to the pagetable. Xen strictly enforces this, and + * will disallow any pagetable update which will end up mapping a + * pagetable page RW, and will disallow using any writable page as a + * pagetable. + * + * Naively, when loading %cr3 with the base of a new pagetable, Xen + * would need to validate the whole pagetable before going on. + * Naturally, this is quite slow. The solution is to "pin" a + * pagetable, which enforces all the constraints on the pagetable even + * when it is not actively in use. This menas that Xen can be assured + * that it is still valid when you do load it into %cr3, and doesn't + * need to revalidate it. + * + * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 + */ +#include <linux/sched.h> +#include <linux/highmem.h> +#include <linux/bug.h> +#include <linux/sched.h> + +#include <asm/pgtable.h> +#include <asm/tlbflush.h> +#include <asm/mmu_context.h> +#include <asm/paravirt.h> + +#include <asm/xen/hypercall.h> +#include <asm/xen/hypervisor.h> + +#include <xen/page.h> +#include <xen/interface/xen.h> + +#include "multicalls.h" +#include "mmu.h" + +xmaddr_t arbitrary_virt_to_machine(unsigned long address) +{ + pte_t *pte = lookup_address(address); + unsigned offset = address & PAGE_MASK; + + BUG_ON(pte == NULL); + + return XMADDR((pte_mfn(*pte) << PAGE_SHIFT) + offset); +} + +void make_lowmem_page_readonly(void *vaddr) +{ + pte_t *pte, ptev; + unsigned long address = (unsigned long)vaddr; + + pte = lookup_address(address); + BUG_ON(pte == NULL); + + ptev = pte_wrprotect(*pte); + + if (HYPERVISOR_update_va_mapping(address, ptev, 0)) + BUG(); +} + +void make_lowmem_page_readwrite(void *vaddr) +{ + pte_t *pte, ptev; + unsigned long address = (unsigned long)vaddr; + + pte = lookup_address(address); + BUG_ON(pte == NULL); + + ptev = pte_mkwrite(*pte); + + if (HYPERVISOR_update_va_mapping(address, ptev, 0)) + BUG(); +} + + +void xen_set_pmd(pmd_t *ptr, pmd_t val) +{ + struct multicall_space mcs; + struct mmu_update *u; + + preempt_disable(); + + mcs = xen_mc_entry(sizeof(*u)); + u = mcs.args; + u->ptr = virt_to_machine(ptr).maddr; + u->val = pmd_val_ma(val); + MULTI_mmu_update(mcs.mc, u, 1, NULL, DOMID_SELF); + + xen_mc_issue(PARAVIRT_LAZY_MMU); + + preempt_enable(); +} + +/* + * Associate a virtual page frame with a given physical page frame + * and protection flags for that frame. + */ +void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + pgd = swapper_pg_dir + pgd_index(vaddr); + if (pgd_none(*pgd)) { + BUG(); + return; + } + pud = pud_offset(pgd, vaddr); + if (pud_none(*pud)) { + BUG(); + return; + } + pmd = pmd_offset(pud, vaddr); + if (pmd_none(*pmd)) { + BUG(); + return; + } + pte = pte_offset_kernel(pmd, vaddr); + /* <mfn,flags> stored as-is, to permit clearing entries */ + xen_set_pte(pte, mfn_pte(mfn, flags)); + + /* + * It's enough to flush this one mapping. + * (PGE mappings get flushed as well) + */ + __flush_tlb_one(vaddr); +} + +void xen_set_pte_at(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, pte_t pteval) +{ + if (mm == current->mm || mm == &init_mm) { + if (xen_get_lazy_mode() == PARAVIRT_LAZY_MMU) { + struct multicall_space mcs; + mcs = xen_mc_entry(0); + + MULTI_update_va_mapping(mcs.mc, addr, pteval, 0); + xen_mc_issue(PARAVIRT_LAZY_MMU); + return; + } else + if (HYPERVISOR_update_va_mapping(addr, pteval, 0) == 0) + return; + } + xen_set_pte(ptep, pteval); +} + +#ifdef CONFIG_X86_PAE +void xen_set_pud(pud_t *ptr, pud_t val) +{ + struct multicall_space mcs; + struct mmu_update *u; + + preempt_disable(); + + mcs = xen_mc_entry(sizeof(*u)); + u = mcs.args; + u->ptr = virt_to_machine(ptr).maddr; + u->val = pud_val_ma(val); + MULTI_mmu_update(mcs.mc, u, 1, NULL, DOMID_SELF); + + xen_mc_issue(PARAVIRT_LAZY_MMU); + + preempt_enable(); +} + +void xen_set_pte(pte_t *ptep, pte_t pte) +{ + ptep->pte_high = pte.pte_high; + smp_wmb(); + ptep->pte_low = pte.pte_low; +} + +void xen_set_pte_atomic(pte_t *ptep, pte_t pte) +{ + set_64bit((u64 *)ptep, pte_val_ma(pte)); +} + +void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) +{ + ptep->pte_low = 0; + smp_wmb(); /* make sure low gets written first */ + ptep->pte_high = 0; +} + +void xen_pmd_clear(pmd_t *pmdp) +{ + xen_set_pmd(pmdp, __pmd(0)); +} + +unsigned long long xen_pte_val(pte_t pte) +{ + unsigned long long ret = 0; + + if (pte.pte_low) { + ret = ((unsigned long long)pte.pte_high << 32) | pte.pte_low; + ret = machine_to_phys(XMADDR(ret)).paddr | 1; + } + + return ret; +} + +unsigned long long xen_pmd_val(pmd_t pmd) +{ + unsigned long long ret = pmd.pmd; + if (ret) + ret = machine_to_phys(XMADDR(ret)).paddr | 1; + return ret; +} + +unsigned long long xen_pgd_val(pgd_t pgd) +{ + unsigned long long ret = pgd.pgd; + if (ret) + ret = machine_to_phys(XMADDR(ret)).paddr | 1; + return ret; +} + +pte_t xen_make_pte(unsigned long long pte) +{ + if (pte & 1) + pte = phys_to_machine(XPADDR(pte)).maddr; + + return (pte_t){ pte, pte >> 32 }; +} + +pmd_t xen_make_pmd(unsigned long long pmd) +{ + if (pmd & 1) + pmd = phys_to_machine(XPADDR(pmd)).maddr; + + return (pmd_t){ pmd }; +} + +pgd_t xen_make_pgd(unsigned long long pgd) +{ + if (pgd & _PAGE_PRESENT) + pgd = phys_to_machine(XPADDR(pgd)).maddr; + + return (pgd_t){ pgd }; +} +#else /* !PAE */ +void xen_set_pte(pte_t *ptep, pte_t pte) +{ + *ptep = pte; +} + +unsigned long xen_pte_val(pte_t pte) +{ + unsigned long ret = pte.pte_low; + + if (ret & _PAGE_PRESENT) + ret = machine_to_phys(XMADDR(ret)).paddr; + + return ret; +} + +unsigned long xen_pgd_val(pgd_t pgd) +{ + unsigned long ret = pgd.pgd; + if (ret) + ret = machine_to_phys(XMADDR(ret)).paddr | 1; + return ret; +} + +pte_t xen_make_pte(unsigned long pte) +{ + if (pte & _PAGE_PRESENT) + pte = phys_to_machine(XPADDR(pte)).maddr; + + return (pte_t){ pte }; +} + +pgd_t xen_make_pgd(unsigned long pgd) +{ + if (pgd & _PAGE_PRESENT) + pgd = phys_to_machine(XPADDR(pgd)).maddr; + + return (pgd_t){ pgd }; +} +#endif /* CONFIG_X86_PAE */ + + + +/* + (Yet another) pagetable walker. This one is intended for pinning a + pagetable. This means that it walks a pagetable and calls the + callback function on each page it finds making up the page table, + at every level. It walks the entire pagetable, but it only bothers + pinning pte pages which are below pte_limit. In the normal case + this will be TASK_SIZE, but at boot we need to pin up to + FIXADDR_TOP. But the important bit is that we don't pin beyond + there, because then we start getting into Xen's ptes. +*/ +static int pgd_walk(pgd_t *pgd_base, int (*func)(struct page *, unsigned), + unsigned long limit) +{ + pgd_t *pgd = pgd_base; + int flush = 0; + unsigned long addr = 0; + unsigned long pgd_next; + + BUG_ON(limit > FIXADDR_TOP); + + if (xen_feature(XENFEAT_auto_translated_physmap)) + return 0; + + for (; addr != FIXADDR_TOP; pgd++, addr = pgd_next) { + pud_t *pud; + unsigned long pud_limit, pud_next; + + pgd_next = pud_limit = pgd_addr_end(addr, FIXADDR_TOP); + + if (!pgd_val(*pgd)) + continue; + + pud = pud_offset(pgd, 0); + + if (PTRS_PER_PUD > 1) /* not folded */ + flush |= (*func)(virt_to_page(pud), 0); + + for (; addr != pud_limit; pud++, addr = pud_next) { + pmd_t *pmd; + unsigned long pmd_limit; + + pud_next = pud_addr_end(addr, pud_limit); + + if (pud_next < limit) + pmd_limit = pud_next; + else + pmd_limit = limit; + + if (pud_none(*pud)) + continue; + + pmd = pmd_offset(pud, 0); + + if (PTRS_PER_PMD > 1) /* not folded */ + flush |= (*func)(virt_to_page(pmd), 0); + + for (; addr != pmd_limit; pmd++) { + addr += (PAGE_SIZE * PTRS_PER_PTE); + if ((pmd_limit-1) < (addr-1)) { + addr = pmd_limit; + break; + } + + if (pmd_none(*pmd)) + continue; + + flush |= (*func)(pmd_page(*pmd), 0); + } + } + } + + flush |= (*func)(virt_to_page(pgd_base), UVMF_TLB_FLUSH); + + return flush; +} + +static int pin_page(struct page *page, unsigned flags) +{ + unsigned pgfl = test_and_set_bit(PG_pinned, &page->flags); + int flush; + + if (pgfl) + flush = 0; /* already pinned */ + else if (PageHighMem(page)) + /* kmaps need flushing if we found an unpinned + highpage */ + flush = 1; + else { + void *pt = lowmem_page_address(page); + unsigned long pfn = page_to_pfn(page); + struct multicall_space mcs = __xen_mc_entry(0); + + flush = 0; + + MULTI_update_va_mapping(mcs.mc, (unsigned long)pt, + pfn_pte(pfn, PAGE_KERNEL_RO), + flags); + } + + return flush; +} + +/* This is called just after a mm has been created, but it has not + been used yet. We need to make sure that its pagetable is all + read-only, and can be pinned. */ +void xen_pgd_pin(pgd_t *pgd) +{ + struct multicall_space mcs; + struct mmuext_op *op; + + xen_mc_batch(); + + if (pgd_walk(pgd, pin_page, TASK_SIZE)) { + /* re-enable interrupts for kmap_flush_unused */ + xen_mc_issue(0); + kmap_flush_unused(); + xen_mc_batch(); + } + + mcs = __xen_mc_entry(sizeof(*op)); + op = mcs.args; + +#ifdef CONFIG_X86_PAE + op->cmd = MMUEXT_PIN_L3_TABLE; +#else + op->cmd = MMUEXT_PIN_L2_TABLE; +#endif + op->arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(pgd))); + MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); + + xen_mc_issue(0); +} + +/* The init_mm pagetable is really pinned as soon as its created, but + that's before we have page structures to store the bits. So do all + the book-keeping now. */ +static __init int mark_pinned(struct page *page, unsigned flags) +{ + SetPagePinned(page); + return 0; +} + +void __init xen_mark_init_mm_pinned(void) +{ + pgd_walk(init_mm.pgd, mark_pinned, FIXADDR_TOP); +} + +static int unpin_page(struct page *page, unsigned flags) +{ + unsigned pgfl = test_and_clear_bit(PG_pinned, &page->flags); + + if (pgfl && !PageHighMem(page)) { + void *pt = lowmem_page_address(page); + unsigned long pfn = page_to_pfn(page); + struct multicall_space mcs = __xen_mc_entry(0); + + MULTI_update_va_mapping(mcs.mc, (unsigned long)pt, + pfn_pte(pfn, PAGE_KERNEL), + flags); + } + + return 0; /* never need to flush on unpin */ +} + +/* Release a pagetables pages back as normal RW */ +static void xen_pgd_unpin(pgd_t *pgd) +{ + struct mmuext_op *op; + struct multicall_space mcs; + + xen_mc_batch(); + + mcs = __xen_mc_entry(sizeof(*op)); + + op = mcs.args; + op->cmd = MMUEXT_UNPIN_TABLE; + op->arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(pgd))); + + MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); + + pgd_walk(pgd, unpin_page, TASK_SIZE); + + xen_mc_issue(0); +} + +void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next) +{ + spin_lock(&next->page_table_lock); + xen_pgd_pin(next->pgd); + spin_unlock(&next->page_table_lock); +} + +void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) +{ + spin_lock(&mm->page_table_lock); + xen_pgd_pin(mm->pgd); + spin_unlock(&mm->page_table_lock); +} + + +#ifdef CONFIG_SMP +/* Another cpu may still have their %cr3 pointing at the pagetable, so + we need to repoint it somewhere else before we can unpin it. */ +static void drop_other_mm_ref(void *info) +{ + struct mm_struct *mm = info; + + if (__get_cpu_var(cpu_tlbstate).active_mm == mm) + leave_mm(smp_processor_id()); +} + +static void drop_mm_ref(struct mm_struct *mm) +{ + if (current->active_mm == mm) { + if (current->mm == mm) + load_cr3(swapper_pg_dir); + else + leave_mm(smp_processor_id()); + } + + if (!cpus_empty(mm->cpu_vm_mask)) + xen_smp_call_function_mask(mm->cpu_vm_mask, drop_other_mm_ref, + mm, 1); +} +#else +static void drop_mm_ref(struct mm_struct *mm) +{ + if (current->active_mm == mm) + load_cr3(swapper_pg_dir); +} +#endif + +/* + * While a process runs, Xen pins its pagetables, which means that the + * hypervisor forces it to be read-only, and it controls all updates + * to it. This means that all pagetable updates have to go via the + * hypervisor, which is moderately expensive. + * + * Since we're pulling the pagetable down, we switch to use init_mm, + * unpin old process pagetable and mark it all read-write, which + * allows further operations on it to be simple memory accesses. + * + * The only subtle point is that another CPU may be still using the + * pagetable because of lazy tlb flushing. This means we need need to + * switch all CPUs off this pagetable before we can unpin it. + */ +void xen_exit_mmap(struct mm_struct *mm) +{ + get_cpu(); /* make sure we don't move around */ + drop_mm_ref(mm); + put_cpu(); + + spin_lock(&mm->page_table_lock); + xen_pgd_unpin(mm->pgd); + spin_unlock(&mm->page_table_lock); +} diff --git a/arch/i386/xen/mmu.h b/arch/i386/xen/mmu.h new file mode 100644 index 00000000000..c9ff27f3ac3 --- /dev/null +++ b/arch/i386/xen/mmu.h @@ -0,0 +1,60 @@ +#ifndef _XEN_MMU_H + +#include <linux/linkage.h> +#include <asm/page.h> + +/* + * Page-directory addresses above 4GB do not fit into architectural %cr3. + * When accessing %cr3, or equivalent field in vcpu_guest_context, guests + * must use the following accessor macros to pack/unpack valid MFNs. + * + * Note that Xen is using the fact that the pagetable base is always + * page-aligned, and putting the 12 MSB of the address into the 12 LSB + * of cr3. + */ +#define xen_pfn_to_cr3(pfn) (((unsigned)(pfn) << 12) | ((unsigned)(pfn) >> 20)) +#define xen_cr3_to_pfn(cr3) (((unsigned)(cr3) >> 12) | ((unsigned)(cr3) << 20)) + + +void set_pte_mfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags); + +void xen_set_pte(pte_t *ptep, pte_t pteval); +void xen_set_pte_at(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, pte_t pteval); +void xen_set_pmd(pmd_t *pmdp, pmd_t pmdval); + +void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next); +void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm); +void xen_exit_mmap(struct mm_struct *mm); + +void xen_pgd_pin(pgd_t *pgd); +//void xen_pgd_unpin(pgd_t *pgd); + +#ifdef CONFIG_X86_PAE +unsigned long long xen_pte_val(pte_t); +unsigned long long xen_pmd_val(pmd_t); +unsigned long long xen_pgd_val(pgd_t); + +pte_t xen_make_pte(unsigned long long); +pmd_t xen_make_pmd(unsigned long long); +pgd_t xen_make_pgd(unsigned long long); + +void xen_set_pte_at(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, pte_t pteval); +void xen_set_pte_atomic(pte_t *ptep, pte_t pte); +void xen_set_pud(pud_t *ptr, pud_t val); +void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep); +void xen_pmd_clear(pmd_t *pmdp); + + +#else +unsigned long xen_pte_val(pte_t); +unsigned long xen_pmd_val(pmd_t); +unsigned long xen_pgd_val(pgd_t); + +pte_t xen_make_pte(unsigned long); +pmd_t xen_make_pmd(unsigned long); +pgd_t xen_make_pgd(unsigned long); +#endif + +#endif /* _XEN_MMU_H */ diff --git a/arch/i386/xen/multicalls.c b/arch/i386/xen/multicalls.c new file mode 100644 index 00000000000..c837e8e463d --- /dev/null +++ b/arch/i386/xen/multicalls.c @@ -0,0 +1,90 @@ +/* + * Xen hypercall batching. + * + * Xen allows multiple hypercalls to be issued at once, using the + * multicall interface. This allows the cost of trapping into the + * hypervisor to be amortized over several calls. + * + * This file implements a simple interface for multicalls. There's a + * per-cpu buffer of outstanding multicalls. When you want to queue a + * multicall for issuing, you can allocate a multicall slot for the + * call and its arguments, along with storage for space which is + * pointed to by the arguments (for passing pointers to structures, + * etc). When the multicall is actually issued, all the space for the + * commands and allocated memory is freed for reuse. + * + * Multicalls are flushed whenever any of the buffers get full, or + * when explicitly requested. There's no way to get per-multicall + * return results back. It will BUG if any of the multicalls fail. + * + * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 + */ +#include <linux/percpu.h> +#include <linux/hardirq.h> + +#include <asm/xen/hypercall.h> + +#include "multicalls.h" + +#define MC_BATCH 32 +#define MC_ARGS (MC_BATCH * 16 / sizeof(u64)) + +struct mc_buffer { + struct multicall_entry entries[MC_BATCH]; + u64 args[MC_ARGS]; + unsigned mcidx, argidx; +}; + +static DEFINE_PER_CPU(struct mc_buffer, mc_buffer); +DEFINE_PER_CPU(unsigned long, xen_mc_irq_flags); + +void xen_mc_flush(void) +{ + struct mc_buffer *b = &__get_cpu_var(mc_buffer); + int ret = 0; + unsigned long flags; + + BUG_ON(preemptible()); + + /* Disable interrupts in case someone comes in and queues + something in the middle */ + local_irq_save(flags); + + if (b->mcidx) { + int i; + + if (HYPERVISOR_multicall(b->entries, b->mcidx) != 0) + BUG(); + for (i = 0; i < b->mcidx; i++) + if (b->entries[i].result < 0) + ret++; + b->mcidx = 0; + b->argidx = 0; + } else + BUG_ON(b->argidx != 0); + + local_irq_restore(flags); + + BUG_ON(ret); +} + +struct multicall_space __xen_mc_entry(size_t args) +{ + struct mc_buffer *b = &__get_cpu_var(mc_buffer); + struct multicall_space ret; + unsigned argspace = (args + sizeof(u64) - 1) / sizeof(u64); + + BUG_ON(preemptible()); + BUG_ON(argspace > MC_ARGS); + + if (b->mcidx == MC_BATCH || + (b->argidx + argspace) > MC_ARGS) + xen_mc_flush(); + + ret.mc = &b->entries[b->mcidx]; + b->mcidx++; + ret.args = &b->args[b->argidx]; + b->argidx += argspace; + + return ret; +} diff --git a/arch/i386/xen/multicalls.h b/arch/i386/xen/multicalls.h new file mode 100644 index 00000000000..e6f7530b156 --- /dev/null +++ b/arch/i386/xen/multicalls.h @@ -0,0 +1,45 @@ +#ifndef _XEN_MULTICALLS_H +#define _XEN_MULTICALLS_H + +#include "xen-ops.h" + +/* Multicalls */ +struct multicall_space +{ + struct multicall_entry *mc; + void *args; +}; + +/* Allocate room for a multicall and its args */ +struct multicall_space __xen_mc_entry(size_t args); + +DECLARE_PER_CPU(unsigned long, xen_mc_irq_flags); + +/* Call to start a batch of multiple __xen_mc_entry()s. Must be + paired with xen_mc_issue() */ +static inline void xen_mc_batch(void) +{ + /* need to disable interrupts until this entry is complete */ + local_irq_save(__get_cpu_var(xen_mc_irq_flags)); +} + +static inline struct multicall_space xen_mc_entry(size_t args) +{ + xen_mc_batch(); + return __xen_mc_entry(args); +} + +/* Flush all pending multicalls */ +void xen_mc_flush(void); + +/* Issue a multicall if we're not in a lazy mode */ +static inline void xen_mc_issue(unsigned mode) +{ + if ((xen_get_lazy_mode() & mode) == 0) + xen_mc_flush(); + + /* restore flags saved in xen_mc_batch */ + local_irq_restore(x86_read_percpu(xen_mc_irq_flags)); +} + +#endif /* _XEN_MULTICALLS_H */ diff --git a/arch/i386/xen/setup.c b/arch/i386/xen/setup.c new file mode 100644 index 00000000000..2fe6eac510f --- /dev/null +++ b/arch/i386/xen/setup.c @@ -0,0 +1,96 @@ +/* + * Machine specific setup for xen + * + * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 + */ + +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/mm.h> +#include <linux/pm.h> + +#include <asm/elf.h> +#include <asm/e820.h> +#include <asm/setup.h> +#include <asm/xen/hypervisor.h> +#include <asm/xen/hypercall.h> + +#include <xen/interface/physdev.h> +#include <xen/features.h> + +#include "xen-ops.h" + +/* These are code, but not functions. Defined in entry.S */ +extern const char xen_hypervisor_callback[]; +extern const char xen_failsafe_callback[]; + +unsigned long *phys_to_machine_mapping; +EXPORT_SYMBOL(phys_to_machine_mapping); + +/** + * machine_specific_memory_setup - Hook for machine specific memory setup. + **/ + +char * __init xen_memory_setup(void) +{ + unsigned long max_pfn = xen_start_info->nr_pages; + + e820.nr_map = 0; + add_memory_region(0, PFN_PHYS(max_pfn), E820_RAM); + + return "Xen"; +} + +static void xen_idle(void) +{ + local_irq_disable(); + + if (need_resched()) + local_irq_enable(); + else { + current_thread_info()->status &= ~TS_POLLING; + smp_mb__after_clear_bit(); + safe_halt(); + current_thread_info()->status |= TS_POLLING; + } +} + +void __init xen_arch_setup(void) +{ + struct physdev_set_iopl set_iopl; + int rc; + + HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments); + HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables); + + if (!xen_feature(XENFEAT_auto_translated_physmap)) + HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_pae_extended_cr3); + + HYPERVISOR_set_callbacks(__KERNEL_CS, (unsigned long)xen_hypervisor_callback, + __KERNEL_CS, (unsigned long)xen_failsafe_callback); + + set_iopl.iopl = 1; + rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); + if (rc != 0) + printk(KERN_INFO "physdev_op failed %d\n", rc); + +#ifdef CONFIG_ACPI + if (!(xen_start_info->flags & SIF_INITDOMAIN)) { + printk(KERN_INFO "ACPI in unprivileged domain disabled\n"); + disable_acpi(); + } +#endif + + memcpy(boot_command_line, xen_start_info->cmd_line, + MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ? + COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE); + + pm_idle = xen_idle; + +#ifdef CONFIG_SMP + /* fill cpus_possible with all available cpus */ + xen_fill_possible_map(); +#endif + + paravirt_disable_iospace(); +} diff --git a/arch/i386/xen/smp.c b/arch/i386/xen/smp.c new file mode 100644 index 00000000000..557b8e24706 --- /dev/null +++ b/arch/i386/xen/smp.c @@ -0,0 +1,404 @@ +/* + * Xen SMP support + * + * This file implements the Xen versions of smp_ops. SMP under Xen is + * very straightforward. Bringing a CPU up is simply a matter of + * loading its initial context and setting it running. + * + * IPIs are handled through the Xen event mechanism. + * + * Because virtual CPUs can be scheduled onto any real CPU, there's no + * useful topology information for the kernel to make use of. As a + * result, all CPUs are treated as if they're single-core and + * single-threaded. + * + * This does not handle HOTPLUG_CPU yet. + */ +#include <linux/sched.h> +#include <linux/err.h> +#include <linux/smp.h> + +#include <asm/paravirt.h> +#include <asm/desc.h> +#include <asm/pgtable.h> +#include <asm/cpu.h> + +#include <xen/interface/xen.h> +#include <xen/interface/vcpu.h> + +#include <asm/xen/interface.h> +#include <asm/xen/hypercall.h> + +#include <xen/page.h> +#include <xen/events.h> + +#include "xen-ops.h" +#include "mmu.h" + +static cpumask_t cpu_initialized_map; +static DEFINE_PER_CPU(int, resched_irq); +static DEFINE_PER_CPU(int, callfunc_irq); + +/* + * Structure and data for smp_call_function(). This is designed to minimise + * static memory requirements. It also looks cleaner. + */ +static DEFINE_SPINLOCK(call_lock); + +struct call_data_struct { + void (*func) (void *info); + void *info; + atomic_t started; + atomic_t finished; + int wait; +}; + +static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id); + +static struct call_data_struct *call_data; + +/* + * Reschedule call back. Nothing to do, + * all the work is done automatically when + * we return from the interrupt. + */ +static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id) +{ + return IRQ_HANDLED; +} + +static __cpuinit void cpu_bringup_and_idle(void) +{ + int cpu = smp_processor_id(); + + cpu_init(); + + preempt_disable(); + per_cpu(cpu_state, cpu) = CPU_ONLINE; + + xen_setup_cpu_clockevents(); + + /* We can take interrupts now: we're officially "up". */ + local_irq_enable(); + + wmb(); /* make sure everything is out */ + cpu_idle(); +} + +static int xen_smp_intr_init(unsigned int cpu) +{ + int rc; + const char *resched_name, *callfunc_name; + + per_cpu(resched_irq, cpu) = per_cpu(callfunc_irq, cpu) = -1; + + resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu); + rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR, + cpu, + xen_reschedule_interrupt, + IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING, + resched_name, + NULL); + if (rc < 0) + goto fail; + per_cpu(resched_irq, cpu) = rc; + + callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu); + rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR, + cpu, + xen_call_function_interrupt, + IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING, + callfunc_name, + NULL); + if (rc < 0) + goto fail; + per_cpu(callfunc_irq, cpu) = rc; + + return 0; + + fail: + if (per_cpu(resched_irq, cpu) >= 0) + unbind_from_irqhandler(per_cpu(resched_irq, cpu), NULL); + if (per_cpu(callfunc_irq, cpu) >= 0) + unbind_from_irqhandler(per_cpu(callfunc_irq, cpu), NULL); + return rc; +} + +void __init xen_fill_possible_map(void) +{ + int i, rc; + + for (i = 0; i < NR_CPUS; i++) { + rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL); + if (rc >= 0) + cpu_set(i, cpu_possible_map); + } +} + +void __init xen_smp_prepare_boot_cpu(void) +{ + int cpu; + + BUG_ON(smp_processor_id() != 0); + native_smp_prepare_boot_cpu(); + + /* We've switched to the "real" per-cpu gdt, so make sure the + old memory can be recycled */ + make_lowmem_page_readwrite(&per_cpu__gdt_page); + + for (cpu = 0; cpu < NR_CPUS; cpu++) { + cpus_clear(cpu_sibling_map[cpu]); + cpus_clear(cpu_core_map[cpu]); + } + + xen_setup_vcpu_info_placement(); +} + +void __init xen_smp_prepare_cpus(unsigned int max_cpus) +{ + unsigned cpu; + + for (cpu = 0; cpu < NR_CPUS; cpu++) { + cpus_clear(cpu_sibling_map[cpu]); + cpus_clear(cpu_core_map[cpu]); + } + + smp_store_cpu_info(0); + set_cpu_sibling_map(0); + + if (xen_smp_intr_init(0)) + BUG(); + + cpu_initialized_map = cpumask_of_cpu(0); + + /* Restrict the possible_map according to max_cpus. */ + while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) { + for (cpu = NR_CPUS-1; !cpu_isset(cpu, cpu_possible_map); cpu--) + continue; + cpu_clear(cpu, cpu_possible_map); + } + + for_each_possible_cpu (cpu) { + struct task_struct *idle; + + if (cpu == 0) + continue; + + idle = fork_idle(cpu); + if (IS_ERR(idle)) + panic("failed fork for CPU %d", cpu); + + cpu_set(cpu, cpu_present_map); + } + + //init_xenbus_allowed_cpumask(); +} + +static __cpuinit int +cpu_initialize_context(unsigned int cpu, struct task_struct *idle) +{ + struct vcpu_guest_context *ctxt; + struct gdt_page *gdt = &per_cpu(gdt_page, cpu); + + if (cpu_test_and_set(cpu, cpu_initialized_map)) + return 0; + + ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL); + if (ctxt == NULL) + return -ENOMEM; + + ctxt->flags = VGCF_IN_KERNEL; + ctxt->user_regs.ds = __USER_DS; + ctxt->user_regs.es = __USER_DS; + ctxt->user_regs.fs = __KERNEL_PERCPU; + ctxt->user_regs.gs = 0; + ctxt->user_regs.ss = __KERNEL_DS; + ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle; + ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */ + + memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt)); + + xen_copy_trap_info(ctxt->trap_ctxt); + + ctxt->ldt_ents = 0; + + BUG_ON((unsigned long)gdt->gdt & ~PAGE_MASK); + make_lowmem_page_readonly(gdt->gdt); + + ctxt->gdt_frames[0] = virt_to_mfn(gdt->gdt); + ctxt->gdt_ents = ARRAY_SIZE(gdt->gdt); + + ctxt->user_regs.cs = __KERNEL_CS; + ctxt->user_regs.esp = idle->thread.esp0 - sizeof(struct pt_regs); + + ctxt->kernel_ss = __KERNEL_DS; + ctxt->kernel_sp = idle->thread.esp0; + + ctxt->event_callback_cs = __KERNEL_CS; + ctxt->event_callback_eip = (unsigned long)xen_hypervisor_callback; + ctxt->failsafe_callback_cs = __KERNEL_CS; + ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback; + + per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir); + ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir)); + + if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt)) + BUG(); + + kfree(ctxt); + return 0; +} + +int __cpuinit xen_cpu_up(unsigned int cpu) +{ + struct task_struct *idle = idle_task(cpu); + int rc; + +#if 0 + rc = cpu_up_check(cpu); + if (rc) + return rc; +#endif + + init_gdt(cpu); + per_cpu(current_task, cpu) = idle; + irq_ctx_init(cpu); + xen_setup_timer(cpu); + + /* make sure interrupts start blocked */ + per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1; + + rc = cpu_initialize_context(cpu, idle); + if (rc) + return rc; + + if (num_online_cpus() == 1) + alternatives_smp_switch(1); + + rc = xen_smp_intr_init(cpu); + if (rc) + return rc; + + smp_store_cpu_info(cpu); + set_cpu_sibling_map(cpu); + /* This must be done before setting cpu_online_map */ + wmb(); + + cpu_set(cpu, cpu_online_map); + + rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL); + BUG_ON(rc); + + return 0; +} + +void xen_smp_cpus_done(unsigned int max_cpus) +{ +} + +static void stop_self(void *v) +{ + int cpu = smp_processor_id(); + + /* make sure we're not pinning something down */ + load_cr3(swapper_pg_dir); + /* should set up a minimal gdt */ + + HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL); + BUG(); +} + +void xen_smp_send_stop(void) +{ + smp_call_function(stop_self, NULL, 0, 0); +} + +void xen_smp_send_reschedule(int cpu) +{ + xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR); +} + + +static void xen_send_IPI_mask(cpumask_t mask, enum ipi_vector vector) +{ + unsigned cpu; + + cpus_and(mask, mask, cpu_online_map); + + for_each_cpu_mask(cpu, mask) + xen_send_IPI_one(cpu, vector); +} + +static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id) +{ + void (*func) (void *info) = call_data->func; + void *info = call_data->info; + int wait = call_data->wait; + + /* + * Notify initiating CPU that I've grabbed the data and am + * about to execute the function + */ + mb(); + atomic_inc(&call_data->started); + /* + * At this point the info structure may be out of scope unless wait==1 + */ + irq_enter(); + (*func)(info); + irq_exit(); + + if (wait) { + mb(); /* commit everything before setting finished */ + atomic_inc(&call_data->finished); + } + + return IRQ_HANDLED; +} + +int xen_smp_call_function_mask(cpumask_t mask, void (*func)(void *), + void *info, int wait) +{ + struct call_data_struct data; + int cpus; + + /* Holding any lock stops cpus from going down. */ + spin_lock(&call_lock); + + cpu_clear(smp_processor_id(), mask); + + cpus = cpus_weight(mask); + if (!cpus) { + spin_unlock(&call_lock); + return 0; + } + + /* Can deadlock when called with interrupts disabled */ + WARN_ON(irqs_disabled()); + + data.func = func; + data.info = info; + atomic_set(&data.started, 0); + data.wait = wait; + if (wait) + atomic_set(&data.finished, 0); + + call_data = &data; + mb(); /* write everything before IPI */ + + /* Send a message to other CPUs and wait for them to respond */ + xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR); + + /* Make sure other vcpus get a chance to run. + XXX too severe? Maybe we should check the other CPU's states? */ + HYPERVISOR_sched_op(SCHEDOP_yield, 0); + + /* Wait for response */ + while (atomic_read(&data.started) != cpus || + (wait && atomic_read(&data.finished) != cpus)) + cpu_relax(); + + spin_unlock(&call_lock); + + return 0; +} diff --git a/arch/i386/xen/time.c b/arch/i386/xen/time.c new file mode 100644 index 00000000000..51fdabf1fd4 --- /dev/null +++ b/arch/i386/xen/time.c @@ -0,0 +1,590 @@ +/* + * Xen time implementation. + * + * This is implemented in terms of a clocksource driver which uses + * the hypervisor clock as a nanosecond timebase, and a clockevent + * driver which uses the hypervisor's timer mechanism. + * + * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 + */ +#include <linux/kernel.h> +#include <linux/interrupt.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> +#include <linux/kernel_stat.h> + +#include <asm/xen/hypervisor.h> +#include <asm/xen/hypercall.h> + +#include <xen/events.h> +#include <xen/interface/xen.h> +#include <xen/interface/vcpu.h> + +#include "xen-ops.h" + +#define XEN_SHIFT 22 + +/* Xen may fire a timer up to this many ns early */ +#define TIMER_SLOP 100000 +#define NS_PER_TICK (1000000000LL / HZ) + +static cycle_t xen_clocksource_read(void); + +/* These are perodically updated in shared_info, and then copied here. */ +struct shadow_time_info { + u64 tsc_timestamp; /* TSC at last update of time vals. */ + u64 system_timestamp; /* Time, in nanosecs, since boot. */ + u32 tsc_to_nsec_mul; + int tsc_shift; + u32 version; +}; + +static DEFINE_PER_CPU(struct shadow_time_info, shadow_time); + +/* runstate info updated by Xen */ +static DEFINE_PER_CPU(struct vcpu_runstate_info, runstate); + +/* snapshots of runstate info */ +static DEFINE_PER_CPU(struct vcpu_runstate_info, runstate_snapshot); + +/* unused ns of stolen and blocked time */ +static DEFINE_PER_CPU(u64, residual_stolen); +static DEFINE_PER_CPU(u64, residual_blocked); + +/* return an consistent snapshot of 64-bit time/counter value */ +static u64 get64(const u64 *p) +{ + u64 ret; + + if (BITS_PER_LONG < 64) { + u32 *p32 = (u32 *)p; + u32 h, l; + + /* + * Read high then low, and then make sure high is + * still the same; this will only loop if low wraps + * and carries into high. + * XXX some clean way to make this endian-proof? + */ + do { + h = p32[1]; + barrier(); + l = p32[0]; + barrier(); + } while (p32[1] != h); + + ret = (((u64)h) << 32) | l; + } else + ret = *p; + + return ret; +} + +/* + * Runstate accounting + */ +static void get_runstate_snapshot(struct vcpu_runstate_info *res) +{ + u64 state_time; + struct vcpu_runstate_info *state; + + BUG_ON(preemptible()); + + state = &__get_cpu_var(runstate); + + /* + * The runstate info is always updated by the hypervisor on + * the current CPU, so there's no need to use anything + * stronger than a compiler barrier when fetching it. + */ + do { + state_time = get64(&state->state_entry_time); + barrier(); + *res = *state; + barrier(); + } while (get64(&state->state_entry_time) != state_time); +} + +static void setup_runstate_info(int cpu) +{ + struct vcpu_register_runstate_memory_area area; + + area.addr.v = &per_cpu(runstate, cpu); + + if (HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area, + cpu, &area)) + BUG(); +} + +static void do_stolen_accounting(void) +{ + struct vcpu_runstate_info state; + struct vcpu_runstate_info *snap; + s64 blocked, runnable, offline, stolen; + cputime_t ticks; + + get_runstate_snapshot(&state); + + WARN_ON(state.state != RUNSTATE_running); + + snap = &__get_cpu_var(runstate_snapshot); + + /* work out how much time the VCPU has not been runn*ing* */ + blocked = state.time[RUNSTATE_blocked] - snap->time[RUNSTATE_blocked]; + runnable = state.time[RUNSTATE_runnable] - snap->time[RUNSTATE_runnable]; + offline = state.time[RUNSTATE_offline] - snap->time[RUNSTATE_offline]; + + *snap = state; + + /* Add the appropriate number of ticks of stolen time, + including any left-overs from last time. Passing NULL to + account_steal_time accounts the time as stolen. */ + stolen = runnable + offline + __get_cpu_var(residual_stolen); + + if (stolen < 0) + stolen = 0; + + ticks = 0; + while (stolen >= NS_PER_TICK) { + ticks++; + stolen -= NS_PER_TICK; + } + __get_cpu_var(residual_stolen) = stolen; + account_steal_time(NULL, ticks); + + /* Add the appropriate number of ticks of blocked time, + including any left-overs from last time. Passing idle to + account_steal_time accounts the time as idle/wait. */ + blocked += __get_cpu_var(residual_blocked); + + if (blocked < 0) + blocked = 0; + + ticks = 0; + while (blocked >= NS_PER_TICK) { + ticks++; + blocked -= NS_PER_TICK; + } + __get_cpu_var(residual_blocked) = blocked; + account_steal_time(idle_task(smp_processor_id()), ticks); +} + +/* + * Xen sched_clock implementation. Returns the number of unstolen + * nanoseconds, which is nanoseconds the VCPU spent in RUNNING+BLOCKED + * states. + */ +unsigned long long xen_sched_clock(void) +{ + struct vcpu_runstate_info state; + cycle_t now; + u64 ret; + s64 offset; + + /* + * Ideally sched_clock should be called on a per-cpu basis + * anyway, so preempt should already be disabled, but that's + * not current practice at the moment. + */ + preempt_disable(); + + now = xen_clocksource_read(); + + get_runstate_snapshot(&state); + + WARN_ON(state.state != RUNSTATE_running); + + offset = now - state.state_entry_time; + if (offset < 0) + offset = 0; + + ret = state.time[RUNSTATE_blocked] + + state.time[RUNSTATE_running] + + offset; + + preempt_enable(); + + return ret; +} + + +/* Get the CPU speed from Xen */ +unsigned long xen_cpu_khz(void) +{ + u64 cpu_khz = 1000000ULL << 32; + const struct vcpu_time_info *info = + &HYPERVISOR_shared_info->vcpu_info[0].time; + + do_div(cpu_khz, info->tsc_to_system_mul); + if (info->tsc_shift < 0) + cpu_khz <<= -info->tsc_shift; + else + cpu_khz >>= info->tsc_shift; + + return cpu_khz; +} + +/* + * Reads a consistent set of time-base values from Xen, into a shadow data + * area. + */ +static unsigned get_time_values_from_xen(void) +{ + struct vcpu_time_info *src; + struct shadow_time_info *dst; + + /* src is shared memory with the hypervisor, so we need to + make sure we get a consistent snapshot, even in the face of + being preempted. */ + src = &__get_cpu_var(xen_vcpu)->time; + dst = &__get_cpu_var(shadow_time); + + do { + dst->version = src->version; + rmb(); /* fetch version before data */ + dst->tsc_timestamp = src->tsc_timestamp; + dst->system_timestamp = src->system_time; + dst->tsc_to_nsec_mul = src->tsc_to_system_mul; + dst->tsc_shift = src->tsc_shift; + rmb(); /* test version after fetching data */ + } while ((src->version & 1) | (dst->version ^ src->version)); + + return dst->version; +} + +/* + * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction, + * yielding a 64-bit result. + */ +static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift) +{ + u64 product; +#ifdef __i386__ + u32 tmp1, tmp2; +#endif + + if (shift < 0) + delta >>= -shift; + else + delta <<= shift; + +#ifdef __i386__ + __asm__ ( + "mul %5 ; " + "mov %4,%%eax ; " + "mov %%edx,%4 ; " + "mul %5 ; " + "xor %5,%5 ; " + "add %4,%%eax ; " + "adc %5,%%edx ; " + : "=A" (product), "=r" (tmp1), "=r" (tmp2) + : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) ); +#elif __x86_64__ + __asm__ ( + "mul %%rdx ; shrd $32,%%rdx,%%rax" + : "=a" (product) : "0" (delta), "d" ((u64)mul_frac) ); +#else +#error implement me! +#endif + + return product; +} + +static u64 get_nsec_offset(struct shadow_time_info *shadow) +{ + u64 now, delta; + now = native_read_tsc(); + delta = now - shadow->tsc_timestamp; + return scale_delta(delta, shadow->tsc_to_nsec_mul, shadow->tsc_shift); +} + +static cycle_t xen_clocksource_read(void) +{ + struct shadow_time_info *shadow = &get_cpu_var(shadow_time); + cycle_t ret; + unsigned version; + + do { + version = get_time_values_from_xen(); + barrier(); + ret = shadow->system_timestamp + get_nsec_offset(shadow); + barrier(); + } while (version != __get_cpu_var(xen_vcpu)->time.version); + + put_cpu_var(shadow_time); + + return ret; +} + +static void xen_read_wallclock(struct timespec *ts) +{ + const struct shared_info *s = HYPERVISOR_shared_info; + u32 version; + u64 delta; + struct timespec now; + + /* get wallclock at system boot */ + do { + version = s->wc_version; + rmb(); /* fetch version before time */ + now.tv_sec = s->wc_sec; + now.tv_nsec = s->wc_nsec; + rmb(); /* fetch time before checking version */ + } while ((s->wc_version & 1) | (version ^ s->wc_version)); + + delta = xen_clocksource_read(); /* time since system boot */ + delta += now.tv_sec * (u64)NSEC_PER_SEC + now.tv_nsec; + + now.tv_nsec = do_div(delta, NSEC_PER_SEC); + now.tv_sec = delta; + + set_normalized_timespec(ts, now.tv_sec, now.tv_nsec); +} + +unsigned long xen_get_wallclock(void) +{ + struct timespec ts; + + xen_read_wallclock(&ts); + + return ts.tv_sec; +} + +int xen_set_wallclock(unsigned long now) +{ + /* do nothing for domU */ + return -1; +} + +static struct clocksource xen_clocksource __read_mostly = { + .name = "xen", + .rating = 400, + .read = xen_clocksource_read, + .mask = ~0, + .mult = 1<<XEN_SHIFT, /* time directly in nanoseconds */ + .shift = XEN_SHIFT, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +/* + Xen clockevent implementation + + Xen has two clockevent implementations: + + The old timer_op one works with all released versions of Xen prior + to version 3.0.4. This version of the hypervisor provides a + single-shot timer with nanosecond resolution. However, sharing the + same event channel is a 100Hz tick which is delivered while the + vcpu is running. We don't care about or use this tick, but it will + cause the core time code to think the timer fired too soon, and + will end up resetting it each time. It could be filtered, but + doing so has complications when the ktime clocksource is not yet + the xen clocksource (ie, at boot time). + + The new vcpu_op-based timer interface allows the tick timer period + to be changed or turned off. The tick timer is not useful as a + periodic timer because events are only delivered to running vcpus. + The one-shot timer can report when a timeout is in the past, so + set_next_event is capable of returning -ETIME when appropriate. + This interface is used when available. +*/ + + +/* + Get a hypervisor absolute time. In theory we could maintain an + offset between the kernel's time and the hypervisor's time, and + apply that to a kernel's absolute timeout. Unfortunately the + hypervisor and kernel times can drift even if the kernel is using + the Xen clocksource, because ntp can warp the kernel's clocksource. +*/ +static s64 get_abs_timeout(unsigned long delta) +{ + return xen_clocksource_read() + delta; +} + +static void xen_timerop_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + /* unsupported */ + WARN_ON(1); + break; + + case CLOCK_EVT_MODE_ONESHOT: + break; + + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + HYPERVISOR_set_timer_op(0); /* cancel timeout */ + break; + } +} + +static int xen_timerop_set_next_event(unsigned long delta, + struct clock_event_device *evt) +{ + WARN_ON(evt->mode != CLOCK_EVT_MODE_ONESHOT); + + if (HYPERVISOR_set_timer_op(get_abs_timeout(delta)) < 0) + BUG(); + + /* We may have missed the deadline, but there's no real way of + knowing for sure. If the event was in the past, then we'll + get an immediate interrupt. */ + + return 0; +} + +static const struct clock_event_device xen_timerop_clockevent = { + .name = "xen", + .features = CLOCK_EVT_FEAT_ONESHOT, + + .max_delta_ns = 0xffffffff, + .min_delta_ns = TIMER_SLOP, + + .mult = 1, + .shift = 0, + .rating = 500, + + .set_mode = xen_timerop_set_mode, + .set_next_event = xen_timerop_set_next_event, +}; + + + +static void xen_vcpuop_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + int cpu = smp_processor_id(); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + WARN_ON(1); /* unsupported */ + break; + + case CLOCK_EVT_MODE_ONESHOT: + if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL)) + BUG(); + break; + + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + if (HYPERVISOR_vcpu_op(VCPUOP_stop_singleshot_timer, cpu, NULL) || + HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL)) + BUG(); + break; + } +} + +static int xen_vcpuop_set_next_event(unsigned long delta, + struct clock_event_device *evt) +{ + int cpu = smp_processor_id(); + struct vcpu_set_singleshot_timer single; + int ret; + + WARN_ON(evt->mode != CLOCK_EVT_MODE_ONESHOT); + + single.timeout_abs_ns = get_abs_timeout(delta); + single.flags = VCPU_SSHOTTMR_future; + + ret = HYPERVISOR_vcpu_op(VCPUOP_set_singleshot_timer, cpu, &single); + + BUG_ON(ret != 0 && ret != -ETIME); + + return ret; +} + +static const struct clock_event_device xen_vcpuop_clockevent = { + .name = "xen", + .features = CLOCK_EVT_FEAT_ONESHOT, + + .max_delta_ns = 0xffffffff, + .min_delta_ns = TIMER_SLOP, + + .mult = 1, + .shift = 0, + .rating = 500, + + .set_mode = xen_vcpuop_set_mode, + .set_next_event = xen_vcpuop_set_next_event, +}; + +static const struct clock_event_device *xen_clockevent = + &xen_timerop_clockevent; +static DEFINE_PER_CPU(struct clock_event_device, xen_clock_events); + +static irqreturn_t xen_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = &__get_cpu_var(xen_clock_events); + irqreturn_t ret; + + ret = IRQ_NONE; + if (evt->event_handler) { + evt->event_handler(evt); + ret = IRQ_HANDLED; + } + + do_stolen_accounting(); + + return ret; +} + +void xen_setup_timer(int cpu) +{ + const char *name; + struct clock_event_device *evt; + int irq; + + printk(KERN_INFO "installing Xen timer for CPU %d\n", cpu); + + name = kasprintf(GFP_KERNEL, "timer%d", cpu); + if (!name) + name = "<timer kasprintf failed>"; + + irq = bind_virq_to_irqhandler(VIRQ_TIMER, cpu, xen_timer_interrupt, + IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING, + name, NULL); + + evt = &per_cpu(xen_clock_events, cpu); + memcpy(evt, xen_clockevent, sizeof(*evt)); + + evt->cpumask = cpumask_of_cpu(cpu); + evt->irq = irq; + + setup_runstate_info(cpu); +} + +void xen_setup_cpu_clockevents(void) +{ + BUG_ON(preemptible()); + + clockevents_register_device(&__get_cpu_var(xen_clock_events)); +} + +__init void xen_time_init(void) +{ + int cpu = smp_processor_id(); + + get_time_values_from_xen(); + + clocksource_register(&xen_clocksource); + + if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL) == 0) { + /* Successfully turned off 100Hz tick, so we have the + vcpuop-based timer interface */ + printk(KERN_DEBUG "Xen: using vcpuop timer interface\n"); + xen_clockevent = &xen_vcpuop_clockevent; + } + + /* Set initial system time with full resolution */ + xen_read_wallclock(&xtime); + set_normalized_timespec(&wall_to_monotonic, + -xtime.tv_sec, -xtime.tv_nsec); + + tsc_disable = 0; + + xen_setup_timer(cpu); + xen_setup_cpu_clockevents(); +} diff --git a/arch/i386/xen/xen-asm.S b/arch/i386/xen/xen-asm.S new file mode 100644 index 00000000000..1a43b60c0c6 --- /dev/null +++ b/arch/i386/xen/xen-asm.S @@ -0,0 +1,291 @@ +/* + Asm versions of Xen pv-ops, suitable for either direct use or inlining. + The inline versions are the same as the direct-use versions, with the + pre- and post-amble chopped off. + + This code is encoded for size rather than absolute efficiency, + with a view to being able to inline as much as possible. + + We only bother with direct forms (ie, vcpu in pda) of the operations + here; the indirect forms are better handled in C, since they're + generally too large to inline anyway. + */ + +#include <linux/linkage.h> + +#include <asm/asm-offsets.h> +#include <asm/thread_info.h> +#include <asm/percpu.h> +#include <asm/processor-flags.h> +#include <asm/segment.h> + +#include <xen/interface/xen.h> + +#define RELOC(x, v) .globl x##_reloc; x##_reloc=v +#define ENDPATCH(x) .globl x##_end; x##_end=. + +/* Pseudo-flag used for virtual NMI, which we don't implement yet */ +#define XEN_EFLAGS_NMI 0x80000000 + +/* + Enable events. This clears the event mask and tests the pending + event status with one and operation. If there are pending + events, then enter the hypervisor to get them handled. + */ +ENTRY(xen_irq_enable_direct) + /* Clear mask and test pending */ + andw $0x00ff, PER_CPU_VAR(xen_vcpu_info)+XEN_vcpu_info_pending + /* Preempt here doesn't matter because that will deal with + any pending interrupts. The pending check may end up being + run on the wrong CPU, but that doesn't hurt. */ + jz 1f +2: call check_events +1: +ENDPATCH(xen_irq_enable_direct) + ret + ENDPROC(xen_irq_enable_direct) + RELOC(xen_irq_enable_direct, 2b+1) + + +/* + Disabling events is simply a matter of making the event mask + non-zero. + */ +ENTRY(xen_irq_disable_direct) + movb $1, PER_CPU_VAR(xen_vcpu_info)+XEN_vcpu_info_mask +ENDPATCH(xen_irq_disable_direct) + ret + ENDPROC(xen_irq_disable_direct) + RELOC(xen_irq_disable_direct, 0) + +/* + (xen_)save_fl is used to get the current interrupt enable status. + Callers expect the status to be in X86_EFLAGS_IF, and other bits + may be set in the return value. We take advantage of this by + making sure that X86_EFLAGS_IF has the right value (and other bits + in that byte are 0), but other bits in the return value are + undefined. We need to toggle the state of the bit, because + Xen and x86 use opposite senses (mask vs enable). + */ +ENTRY(xen_save_fl_direct) + testb $0xff, PER_CPU_VAR(xen_vcpu_info)+XEN_vcpu_info_mask + setz %ah + addb %ah,%ah +ENDPATCH(xen_save_fl_direct) + ret + ENDPROC(xen_save_fl_direct) + RELOC(xen_save_fl_direct, 0) + + +/* + In principle the caller should be passing us a value return + from xen_save_fl_direct, but for robustness sake we test only + the X86_EFLAGS_IF flag rather than the whole byte. After + setting the interrupt mask state, it checks for unmasked + pending events and enters the hypervisor to get them delivered + if so. + */ +ENTRY(xen_restore_fl_direct) + testb $X86_EFLAGS_IF>>8, %ah + setz PER_CPU_VAR(xen_vcpu_info)+XEN_vcpu_info_mask + /* Preempt here doesn't matter because that will deal with + any pending interrupts. The pending check may end up being + run on the wrong CPU, but that doesn't hurt. */ + + /* check for unmasked and pending */ + cmpw $0x0001, PER_CPU_VAR(xen_vcpu_info)+XEN_vcpu_info_pending + jz 1f +2: call check_events +1: +ENDPATCH(xen_restore_fl_direct) + ret + ENDPROC(xen_restore_fl_direct) + RELOC(xen_restore_fl_direct, 2b+1) + +/* + This is run where a normal iret would be run, with the same stack setup: + 8: eflags + 4: cs + esp-> 0: eip + + This attempts to make sure that any pending events are dealt + with on return to usermode, but there is a small window in + which an event can happen just before entering usermode. If + the nested interrupt ends up setting one of the TIF_WORK_MASK + pending work flags, they will not be tested again before + returning to usermode. This means that a process can end up + with pending work, which will be unprocessed until the process + enters and leaves the kernel again, which could be an + unbounded amount of time. This means that a pending signal or + reschedule event could be indefinitely delayed. + + The fix is to notice a nested interrupt in the critical + window, and if one occurs, then fold the nested interrupt into + the current interrupt stack frame, and re-process it + iteratively rather than recursively. This means that it will + exit via the normal path, and all pending work will be dealt + with appropriately. + + Because the nested interrupt handler needs to deal with the + current stack state in whatever form its in, we keep things + simple by only using a single register which is pushed/popped + on the stack. + + Non-direct iret could be done in the same way, but it would + require an annoying amount of code duplication. We'll assume + that direct mode will be the common case once the hypervisor + support becomes commonplace. + */ +ENTRY(xen_iret_direct) + /* test eflags for special cases */ + testl $(X86_EFLAGS_VM | XEN_EFLAGS_NMI), 8(%esp) + jnz hyper_iret + + push %eax + ESP_OFFSET=4 # bytes pushed onto stack + + /* Store vcpu_info pointer for easy access. Do it this + way to avoid having to reload %fs */ +#ifdef CONFIG_SMP + GET_THREAD_INFO(%eax) + movl TI_cpu(%eax),%eax + movl __per_cpu_offset(,%eax,4),%eax + lea per_cpu__xen_vcpu_info(%eax),%eax +#else + movl $per_cpu__xen_vcpu_info, %eax +#endif + + /* check IF state we're restoring */ + testb $X86_EFLAGS_IF>>8, 8+1+ESP_OFFSET(%esp) + + /* Maybe enable events. Once this happens we could get a + recursive event, so the critical region starts immediately + afterwards. However, if that happens we don't end up + resuming the code, so we don't have to be worried about + being preempted to another CPU. */ + setz XEN_vcpu_info_mask(%eax) +xen_iret_start_crit: + + /* check for unmasked and pending */ + cmpw $0x0001, XEN_vcpu_info_pending(%eax) + + /* If there's something pending, mask events again so we + can jump back into xen_hypervisor_callback */ + sete XEN_vcpu_info_mask(%eax) + + popl %eax + + /* From this point on the registers are restored and the stack + updated, so we don't need to worry about it if we're preempted */ +iret_restore_end: + + /* Jump to hypervisor_callback after fixing up the stack. + Events are masked, so jumping out of the critical + region is OK. */ + je xen_hypervisor_callback + + iret +xen_iret_end_crit: + +hyper_iret: + /* put this out of line since its very rarely used */ + jmp hypercall_page + __HYPERVISOR_iret * 32 + + .globl xen_iret_start_crit, xen_iret_end_crit + +/* + This is called by xen_hypervisor_callback in entry.S when it sees + that the EIP at the time of interrupt was between xen_iret_start_crit + and xen_iret_end_crit. We're passed the EIP in %eax so we can do + a more refined determination of what to do. + + The stack format at this point is: + ---------------- + ss : (ss/esp may be present if we came from usermode) + esp : + eflags } outer exception info + cs } + eip } + ---------------- <- edi (copy dest) + eax : outer eax if it hasn't been restored + ---------------- + eflags } nested exception info + cs } (no ss/esp because we're nested + eip } from the same ring) + orig_eax }<- esi (copy src) + - - - - - - - - + fs } + es } + ds } SAVE_ALL state + eax } + : : + ebx } + ---------------- + return addr <- esp + ---------------- + + In order to deliver the nested exception properly, we need to shift + everything from the return addr up to the error code so it + sits just under the outer exception info. This means that when we + handle the exception, we do it in the context of the outer exception + rather than starting a new one. + + The only caveat is that if the outer eax hasn't been + restored yet (ie, it's still on stack), we need to insert + its value into the SAVE_ALL state before going on, since + it's usermode state which we eventually need to restore. + */ +ENTRY(xen_iret_crit_fixup) + /* offsets +4 for return address */ + + /* + Paranoia: Make sure we're really coming from userspace. + One could imagine a case where userspace jumps into the + critical range address, but just before the CPU delivers a GP, + it decides to deliver an interrupt instead. Unlikely? + Definitely. Easy to avoid? Yes. The Intel documents + explicitly say that the reported EIP for a bad jump is the + jump instruction itself, not the destination, but some virtual + environments get this wrong. + */ + movl PT_CS+4(%esp), %ecx + andl $SEGMENT_RPL_MASK, %ecx + cmpl $USER_RPL, %ecx + je 2f + + lea PT_ORIG_EAX+4(%esp), %esi + lea PT_EFLAGS+4(%esp), %edi + + /* If eip is before iret_restore_end then stack + hasn't been restored yet. */ + cmp $iret_restore_end, %eax + jae 1f + + movl 0+4(%edi),%eax /* copy EAX */ + movl %eax, PT_EAX+4(%esp) + + lea ESP_OFFSET(%edi),%edi /* move dest up over saved regs */ + + /* set up the copy */ +1: std + mov $(PT_EIP+4) / 4, %ecx /* copy ret+saved regs up to orig_eax */ + rep movsl + cld + + lea 4(%edi),%esp /* point esp to new frame */ +2: ret + + +/* + Force an event check by making a hypercall, + but preserve regs before making the call. + */ +check_events: + push %eax + push %ecx + push %edx + call force_evtchn_callback + pop %edx + pop %ecx + pop %eax + ret diff --git a/arch/i386/xen/xen-head.S b/arch/i386/xen/xen-head.S new file mode 100644 index 00000000000..2998d55a001 --- /dev/null +++ b/arch/i386/xen/xen-head.S @@ -0,0 +1,36 @@ +/* Xen-specific pieces of head.S, intended to be included in the right + place in head.S */ + +#ifdef CONFIG_XEN + +#include <linux/elfnote.h> +#include <asm/boot.h> +#include <xen/interface/elfnote.h> + +ENTRY(startup_xen) + movl %esi,xen_start_info + cld + movl $(init_thread_union+THREAD_SIZE),%esp + jmp xen_start_kernel + +.pushsection ".bss.page_aligned" + .align PAGE_SIZE_asm +ENTRY(hypercall_page) + .skip 0x1000 +.popsection + + ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS, .asciz "linux") + ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION, .asciz "2.6") + ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION, .asciz "xen-3.0") + ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE, .long __PAGE_OFFSET) + ELFNOTE(Xen, XEN_ELFNOTE_ENTRY, .long startup_xen) + ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, .long hypercall_page) + ELFNOTE(Xen, XEN_ELFNOTE_FEATURES, .asciz "!writable_page_tables|pae_pgdir_above_4gb") +#ifdef CONFIG_X86_PAE + ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE, .asciz "yes") +#else + ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE, .asciz "no") +#endif + ELFNOTE(Xen, XEN_ELFNOTE_LOADER, .asciz "generic") + +#endif /*CONFIG_XEN */ diff --git a/arch/i386/xen/xen-ops.h b/arch/i386/xen/xen-ops.h new file mode 100644 index 00000000000..b9aaea45f07 --- /dev/null +++ b/arch/i386/xen/xen-ops.h @@ -0,0 +1,71 @@ +#ifndef XEN_OPS_H +#define XEN_OPS_H + +#include <linux/init.h> + +/* These are code, but not functions. Defined in entry.S */ +extern const char xen_hypervisor_callback[]; +extern const char xen_failsafe_callback[]; + +void xen_copy_trap_info(struct trap_info *traps); + +DECLARE_PER_CPU(struct vcpu_info *, xen_vcpu); +DECLARE_PER_CPU(unsigned long, xen_cr3); + +extern struct start_info *xen_start_info; +extern struct shared_info *HYPERVISOR_shared_info; + +char * __init xen_memory_setup(void); +void __init xen_arch_setup(void); +void __init xen_init_IRQ(void); + +void xen_setup_timer(int cpu); +void xen_setup_cpu_clockevents(void); +unsigned long xen_cpu_khz(void); +void __init xen_time_init(void); +unsigned long xen_get_wallclock(void); +int xen_set_wallclock(unsigned long time); +unsigned long long xen_sched_clock(void); + +void xen_mark_init_mm_pinned(void); + +DECLARE_PER_CPU(enum paravirt_lazy_mode, xen_lazy_mode); + +static inline unsigned xen_get_lazy_mode(void) +{ + return x86_read_percpu(xen_lazy_mode); +} + +void __init xen_fill_possible_map(void); + +void __init xen_setup_vcpu_info_placement(void); +void xen_smp_prepare_boot_cpu(void); +void xen_smp_prepare_cpus(unsigned int max_cpus); +int xen_cpu_up(unsigned int cpu); +void xen_smp_cpus_done(unsigned int max_cpus); + +void xen_smp_send_stop(void); +void xen_smp_send_reschedule(int cpu); +int xen_smp_call_function (void (*func) (void *info), void *info, int nonatomic, + int wait); +int xen_smp_call_function_single(int cpu, void (*func) (void *info), void *info, + int nonatomic, int wait); + +int xen_smp_call_function_mask(cpumask_t mask, void (*func)(void *), + void *info, int wait); + + +/* Declare an asm function, along with symbols needed to make it + inlineable */ +#define DECL_ASM(ret, name, ...) \ + ret name(__VA_ARGS__); \ + extern char name##_end[]; \ + extern char name##_reloc[] \ + +DECL_ASM(void, xen_irq_enable_direct, void); +DECL_ASM(void, xen_irq_disable_direct, void); +DECL_ASM(unsigned long, xen_save_fl_direct, void); +DECL_ASM(void, xen_restore_fl_direct, unsigned long); + +void xen_iret_direct(void); +#endif /* XEN_OPS_H */ |