From d3561b7fa0fb0fc583bab0eeda32bec9e4c4056d Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 7 Dec 2006 02:14:07 +0100 Subject: [PATCH] paravirt: header and stubs for paravirtualisation Create a paravirt.h header for all the critical operations which need to be replaced with hypervisor calls, and include that instead of defining native operations, when CONFIG_PARAVIRT. This patch does the dumbest possible replacement of paravirtualized instructions: calls through a "paravirt_ops" structure. Currently these are function implementations of native hardware: hypervisors will override the ops structure with their own variants. All the pv-ops functions are declared "fastcall" so that a specific register-based ABI is used, to make inlining assember easier. And: +From: Andy Whitcroft The paravirt ops introduce a 'weak' attribute onto memory_setup(). Code ordering leads to the following warnings on x86: arch/i386/kernel/setup.c:651: warning: weak declaration of `memory_setup' after first use results in unspecified behavior Move memory_setup() to avoid this. Signed-off-by: Rusty Russell Signed-off-by: Chris Wright Signed-off-by: Andi Kleen Cc: Jeremy Fitzhardinge Cc: Zachary Amsden Signed-off-by: Andrew Morton Signed-off-by: Andy Whitcroft --- arch/i386/Kconfig | 11 ++ arch/i386/boot/compressed/misc.c | 1 + arch/i386/kernel/Makefile | 1 + arch/i386/kernel/asm-offsets.c | 10 + arch/i386/kernel/entry.S | 34 +++- arch/i386/kernel/i8259.c | 5 +- arch/i386/kernel/paravirt.c | 404 +++++++++++++++++++++++++++++++++++++++ arch/i386/kernel/setup.c | 8 +- arch/i386/kernel/smpboot.c | 5 + arch/i386/kernel/time.c | 15 +- arch/i386/power/cpu.c | 8 +- 11 files changed, 479 insertions(+), 23 deletions(-) create mode 100644 arch/i386/kernel/paravirt.c (limited to 'arch') diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig index 1f0f7b60995..bb1fa061c6c 100644 --- a/arch/i386/Kconfig +++ b/arch/i386/Kconfig @@ -182,6 +182,17 @@ config X86_ES7000 endchoice +config PARAVIRT + bool "Paravirtualization support (EXPERIMENTAL)" + depends on EXPERIMENTAL + help + Paravirtualization is a way of running multiple instances of + Linux on the same machine, under a hypervisor. This option + changes the kernel so it can modify itself when it is run + under a hypervisor, improving performance significantly. + However, when run without a hypervisor the kernel is + theoretically slower. If in doubt, say N. + config ACPI_SRAT bool default y diff --git a/arch/i386/boot/compressed/misc.c b/arch/i386/boot/compressed/misc.c index dc153893155..c6798c75c67 100644 --- a/arch/i386/boot/compressed/misc.c +++ b/arch/i386/boot/compressed/misc.c @@ -9,6 +9,7 @@ * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996 */ +#undef CONFIG_PARAVIRT #include #include #include diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile index f614854bd71..40661213604 100644 --- a/arch/i386/kernel/Makefile +++ b/arch/i386/kernel/Makefile @@ -39,6 +39,7 @@ obj-$(CONFIG_VM86) += vm86.o obj-$(CONFIG_EARLY_PRINTK) += early_printk.o obj-$(CONFIG_HPET_TIMER) += hpet.o obj-$(CONFIG_K8_NB) += k8.o +obj-$(CONFIG_PARAVIRT) += paravirt.o EXTRA_AFLAGS := -traditional diff --git a/arch/i386/kernel/asm-offsets.c b/arch/i386/kernel/asm-offsets.c index 0666eb0ed7b..1b2f3cd3327 100644 --- a/arch/i386/kernel/asm-offsets.c +++ b/arch/i386/kernel/asm-offsets.c @@ -101,4 +101,14 @@ void foo(void) BLANK(); OFFSET(PDA_cpu, i386_pda, cpu_number); OFFSET(PDA_pcurrent, i386_pda, pcurrent); + +#ifdef CONFIG_PARAVIRT + BLANK(); + OFFSET(PARAVIRT_enabled, paravirt_ops, paravirt_enabled); + OFFSET(PARAVIRT_irq_disable, paravirt_ops, irq_disable); + OFFSET(PARAVIRT_irq_enable, paravirt_ops, irq_enable); + OFFSET(PARAVIRT_irq_enable_sysexit, paravirt_ops, irq_enable_sysexit); + OFFSET(PARAVIRT_iret, paravirt_ops, iret); + OFFSET(PARAVIRT_read_cr0, paravirt_ops, read_cr0); +#endif } diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S index 0220bc8cbb4..d274612e05c 100644 --- a/arch/i386/kernel/entry.S +++ b/arch/i386/kernel/entry.S @@ -62,13 +62,6 @@ DF_MASK = 0x00000400 NT_MASK = 0x00004000 VM_MASK = 0x00020000 -/* These are replaces for paravirtualization */ -#define DISABLE_INTERRUPTS cli -#define ENABLE_INTERRUPTS sti -#define ENABLE_INTERRUPTS_SYSEXIT sti; sysexit -#define INTERRUPT_RETURN iret -#define GET_CR0_INTO_EAX movl %cr0, %eax - #ifdef CONFIG_PREEMPT #define preempt_stop DISABLE_INTERRUPTS; TRACE_IRQS_OFF #else @@ -416,6 +409,20 @@ ldt_ss: jnz restore_nocheck testl $0x00400000, %eax # returning to 32bit stack? jnz restore_nocheck # allright, normal return + +#ifdef CONFIG_PARAVIRT + /* + * The kernel can't run on a non-flat stack if paravirt mode + * is active. Rather than try to fixup the high bits of + * ESP, bypass this code entirely. This may break DOSemu + * and/or Wine support in a paravirt VM, although the option + * is still available to implement the setting of the high + * 16-bits in the INTERRUPT_RETURN paravirt-op. + */ + cmpl $0, paravirt_ops+PARAVIRT_enabled + jne restore_nocheck +#endif + /* If returning to userspace with 16bit stack, * try to fix the higher word of ESP, as the CPU * won't restore it. @@ -833,6 +840,19 @@ nmi_espfix_stack: .previous KPROBE_END(nmi) +#ifdef CONFIG_PARAVIRT +ENTRY(native_iret) +1: iret +.section __ex_table,"a" + .align 4 + .long 1b,iret_exc +.previous + +ENTRY(native_irq_enable_sysexit) + sti + sysexit +#endif + KPROBE_ENTRY(int3) RING0_INT_FRAME pushl $-1 # mark this as an int diff --git a/arch/i386/kernel/i8259.c b/arch/i386/kernel/i8259.c index 62996cd1708..c8d45821c78 100644 --- a/arch/i386/kernel/i8259.c +++ b/arch/i386/kernel/i8259.c @@ -381,7 +381,10 @@ void __init init_ISA_irqs (void) } } -void __init init_IRQ(void) +/* Overridden in paravirt.c */ +void init_IRQ(void) __attribute__((weak, alias("native_init_IRQ"))); + +void __init native_init_IRQ(void) { int i; diff --git a/arch/i386/kernel/paravirt.c b/arch/i386/kernel/paravirt.c new file mode 100644 index 00000000000..478192cd4b9 --- /dev/null +++ b/arch/i386/kernel/paravirt.c @@ -0,0 +1,404 @@ +/* Paravirtualization interfaces + Copyright (C) 2006 Rusty Russell IBM Corporation + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA +*/ +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include + +/* nop stub */ +static void native_nop(void) +{ +} + +static void __init default_banner(void) +{ + printk(KERN_INFO "Booting paravirtualized kernel on %s\n", + paravirt_ops.name); +} + +char *memory_setup(void) +{ + return paravirt_ops.memory_setup(); +} + +static fastcall unsigned long native_get_debugreg(int regno) +{ + unsigned long val = 0; /* Damn you, gcc! */ + + switch (regno) { + case 0: + asm("movl %%db0, %0" :"=r" (val)); break; + case 1: + asm("movl %%db1, %0" :"=r" (val)); break; + case 2: + asm("movl %%db2, %0" :"=r" (val)); break; + case 3: + asm("movl %%db3, %0" :"=r" (val)); break; + case 6: + asm("movl %%db6, %0" :"=r" (val)); break; + case 7: + asm("movl %%db7, %0" :"=r" (val)); break; + default: + BUG(); + } + return val; +} + +static fastcall void native_set_debugreg(int regno, unsigned long value) +{ + switch (regno) { + case 0: + asm("movl %0,%%db0" : /* no output */ :"r" (value)); + break; + case 1: + asm("movl %0,%%db1" : /* no output */ :"r" (value)); + break; + case 2: + asm("movl %0,%%db2" : /* no output */ :"r" (value)); + break; + case 3: + asm("movl %0,%%db3" : /* no output */ :"r" (value)); + break; + case 6: + asm("movl %0,%%db6" : /* no output */ :"r" (value)); + break; + case 7: + asm("movl %0,%%db7" : /* no output */ :"r" (value)); + break; + default: + BUG(); + } +} + +void init_IRQ(void) +{ + paravirt_ops.init_IRQ(); +} + +static fastcall void native_clts(void) +{ + asm volatile ("clts"); +} + +static fastcall unsigned long native_read_cr0(void) +{ + unsigned long val; + asm volatile("movl %%cr0,%0\n\t" :"=r" (val)); + return val; +} + +static fastcall void native_write_cr0(unsigned long val) +{ + asm volatile("movl %0,%%cr0": :"r" (val)); +} + +static fastcall unsigned long native_read_cr2(void) +{ + unsigned long val; + asm volatile("movl %%cr2,%0\n\t" :"=r" (val)); + return val; +} + +static fastcall void native_write_cr2(unsigned long val) +{ + asm volatile("movl %0,%%cr2": :"r" (val)); +} + +static fastcall unsigned long native_read_cr3(void) +{ + unsigned long val; + asm volatile("movl %%cr3,%0\n\t" :"=r" (val)); + return val; +} + +static fastcall void native_write_cr3(unsigned long val) +{ + asm volatile("movl %0,%%cr3": :"r" (val)); +} + +static fastcall unsigned long native_read_cr4(void) +{ + unsigned long val; + asm volatile("movl %%cr4,%0\n\t" :"=r" (val)); + return val; +} + +static fastcall unsigned long native_read_cr4_safe(void) +{ + unsigned long val; + /* This could fault if %cr4 does not exist */ + asm("1: movl %%cr4, %0 \n" + "2: \n" + ".section __ex_table,\"a\" \n" + ".long 1b,2b \n" + ".previous \n" + : "=r" (val): "0" (0)); + return val; +} + +static fastcall void native_write_cr4(unsigned long val) +{ + asm volatile("movl %0,%%cr4": :"r" (val)); +} + +static fastcall unsigned long native_save_fl(void) +{ + unsigned long f; + asm volatile("pushfl ; popl %0":"=g" (f): /* no input */); + return f; +} + +static fastcall void native_restore_fl(unsigned long f) +{ + asm volatile("pushl %0 ; popfl": /* no output */ + :"g" (f) + :"memory", "cc"); +} + +static fastcall void native_irq_disable(void) +{ + asm volatile("cli": : :"memory"); +} + +static fastcall void native_irq_enable(void) +{ + asm volatile("sti": : :"memory"); +} + +static fastcall void native_safe_halt(void) +{ + asm volatile("sti; hlt": : :"memory"); +} + +static fastcall void native_halt(void) +{ + asm volatile("hlt": : :"memory"); +} + +static fastcall void native_wbinvd(void) +{ + asm volatile("wbinvd": : :"memory"); +} + +static fastcall unsigned long long native_read_msr(unsigned int msr, int *err) +{ + unsigned long long val; + + asm volatile("2: rdmsr ; xorl %0,%0\n" + "1:\n\t" + ".section .fixup,\"ax\"\n\t" + "3: movl %3,%0 ; jmp 1b\n\t" + ".previous\n\t" + ".section __ex_table,\"a\"\n" + " .align 4\n\t" + " .long 2b,3b\n\t" + ".previous" + : "=r" (*err), "=A" (val) + : "c" (msr), "i" (-EFAULT)); + + return val; +} + +static fastcall int native_write_msr(unsigned int msr, unsigned long long val) +{ + int err; + asm volatile("2: wrmsr ; xorl %0,%0\n" + "1:\n\t" + ".section .fixup,\"ax\"\n\t" + "3: movl %4,%0 ; jmp 1b\n\t" + ".previous\n\t" + ".section __ex_table,\"a\"\n" + " .align 4\n\t" + " .long 2b,3b\n\t" + ".previous" + : "=a" (err) + : "c" (msr), "0" ((u32)val), "d" ((u32)(val>>32)), + "i" (-EFAULT)); + return err; +} + +static fastcall unsigned long long native_read_tsc(void) +{ + unsigned long long val; + asm volatile("rdtsc" : "=A" (val)); + return val; +} + +static fastcall unsigned long long native_read_pmc(void) +{ + unsigned long long val; + asm volatile("rdpmc" : "=A" (val)); + return val; +} + +static fastcall void native_load_tr_desc(void) +{ + asm volatile("ltr %w0"::"q" (GDT_ENTRY_TSS*8)); +} + +static fastcall void native_load_gdt(const struct Xgt_desc_struct *dtr) +{ + asm volatile("lgdt %0"::"m" (*dtr)); +} + +static fastcall void native_load_idt(const struct Xgt_desc_struct *dtr) +{ + asm volatile("lidt %0"::"m" (*dtr)); +} + +static fastcall void native_store_gdt(struct Xgt_desc_struct *dtr) +{ + asm ("sgdt %0":"=m" (*dtr)); +} + +static fastcall void native_store_idt(struct Xgt_desc_struct *dtr) +{ + asm ("sidt %0":"=m" (*dtr)); +} + +static fastcall unsigned long native_store_tr(void) +{ + unsigned long tr; + asm ("str %0":"=r" (tr)); + return tr; +} + +static fastcall void native_load_tls(struct thread_struct *t, unsigned int cpu) +{ +#define C(i) get_cpu_gdt_table(cpu)[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i] + C(0); C(1); C(2); +#undef C +} + +static inline void native_write_dt_entry(void *dt, int entry, u32 entry_low, u32 entry_high) +{ + u32 *lp = (u32 *)((char *)dt + entry*8); + lp[0] = entry_low; + lp[1] = entry_high; +} + +static fastcall void native_write_ldt_entry(void *dt, int entrynum, u32 low, u32 high) +{ + native_write_dt_entry(dt, entrynum, low, high); +} + +static fastcall void native_write_gdt_entry(void *dt, int entrynum, u32 low, u32 high) +{ + native_write_dt_entry(dt, entrynum, low, high); +} + +static fastcall void native_write_idt_entry(void *dt, int entrynum, u32 low, u32 high) +{ + native_write_dt_entry(dt, entrynum, low, high); +} + +static fastcall void native_load_esp0(struct tss_struct *tss, + struct thread_struct *thread) +{ + tss->esp0 = thread->esp0; + + /* This can only happen when SEP is enabled, no need to test "SEP"arately */ + if (unlikely(tss->ss1 != thread->sysenter_cs)) { + tss->ss1 = thread->sysenter_cs; + wrmsr(MSR_IA32_SYSENTER_CS, thread->sysenter_cs, 0); + } +} + +static fastcall void native_io_delay(void) +{ + asm volatile("outb %al,$0x80"); +} + +/* These are in entry.S */ +extern fastcall void native_iret(void); +extern fastcall void native_irq_enable_sysexit(void); + +static int __init print_banner(void) +{ + paravirt_ops.banner(); + return 0; +} +core_initcall(print_banner); + +struct paravirt_ops paravirt_ops = { + .name = "bare hardware", + .paravirt_enabled = 0, + .kernel_rpl = 0, + + .banner = default_banner, + .arch_setup = native_nop, + .memory_setup = machine_specific_memory_setup, + .get_wallclock = native_get_wallclock, + .set_wallclock = native_set_wallclock, + .time_init = time_init_hook, + .init_IRQ = native_init_IRQ, + + .cpuid = native_cpuid, + .get_debugreg = native_get_debugreg, + .set_debugreg = native_set_debugreg, + .clts = native_clts, + .read_cr0 = native_read_cr0, + .write_cr0 = native_write_cr0, + .read_cr2 = native_read_cr2, + .write_cr2 = native_write_cr2, + .read_cr3 = native_read_cr3, + .write_cr3 = native_write_cr3, + .read_cr4 = native_read_cr4, + .read_cr4_safe = native_read_cr4_safe, + .write_cr4 = native_write_cr4, + .save_fl = native_save_fl, + .restore_fl = native_restore_fl, + .irq_disable = native_irq_disable, + .irq_enable = native_irq_enable, + .safe_halt = native_safe_halt, + .halt = native_halt, + .wbinvd = native_wbinvd, + .read_msr = native_read_msr, + .write_msr = native_write_msr, + .read_tsc = native_read_tsc, + .read_pmc = native_read_pmc, + .load_tr_desc = native_load_tr_desc, + .set_ldt = native_set_ldt, + .load_gdt = native_load_gdt, + .load_idt = native_load_idt, + .store_gdt = native_store_gdt, + .store_idt = native_store_idt, + .store_tr = native_store_tr, + .load_tls = native_load_tls, + .write_ldt_entry = native_write_ldt_entry, + .write_gdt_entry = native_write_gdt_entry, + .write_idt_entry = native_write_idt_entry, + .load_esp0 = native_load_esp0, + + .set_iopl_mask = native_set_iopl_mask, + .io_delay = native_io_delay, + .const_udelay = __const_udelay, + + .irq_enable_sysexit = native_irq_enable_sysexit, + .iret = native_iret, +}; +EXPORT_SYMBOL(paravirt_ops); diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c index e5bb87aa5a4..695d53fd14d 100644 --- a/arch/i386/kernel/setup.c +++ b/arch/i386/kernel/setup.c @@ -495,6 +495,12 @@ static void set_mca_bus(int x) static void set_mca_bus(int x) { } #endif +/* Overridden in paravirt.c if CONFIG_PARAVIRT */ +char * __attribute__((weak)) memory_setup(void) +{ + return machine_specific_memory_setup(); +} + /* * Determine if we were loaded by an EFI loader. If so, then we have also been * passed the efi memmap, systab, etc., so we should use these data structures @@ -547,7 +553,7 @@ void __init setup_arch(char **cmdline_p) efi_init(); else { printk(KERN_INFO "BIOS-provided physical RAM map:\n"); - print_memory_map(machine_specific_memory_setup()); + print_memory_map(memory_setup()); } copy_edd(); diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c index 095636620fa..cd7de9c9654 100644 --- a/arch/i386/kernel/smpboot.c +++ b/arch/i386/kernel/smpboot.c @@ -33,6 +33,11 @@ * Dave Jones : Report invalid combinations of Athlon CPUs. * Rusty Russell : Hacked into shape for new "hotplug" boot process. */ + +/* SMP boot always wants to use real time delay to allow sufficient time for + * the APs to come online */ +#define USE_REAL_TIME_DELAY + #include #include #include diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c index 78af572fd17..c505b16c099 100644 --- a/arch/i386/kernel/time.c +++ b/arch/i386/kernel/time.c @@ -56,6 +56,7 @@ #include #include #include +#include #include "mach_time.h" @@ -116,10 +117,7 @@ static int set_rtc_mmss(unsigned long nowtime) /* gets recalled with irq locally disabled */ /* XXX - does irqsave resolve this? -johnstul */ spin_lock_irqsave(&rtc_lock, flags); - if (efi_enabled) - retval = efi_set_rtc_mmss(nowtime); - else - retval = mach_set_rtc_mmss(nowtime); + retval = set_wallclock(nowtime); spin_unlock_irqrestore(&rtc_lock, flags); return retval; @@ -223,10 +221,7 @@ unsigned long get_cmos_time(void) spin_lock_irqsave(&rtc_lock, flags); - if (efi_enabled) - retval = efi_get_time(); - else - retval = mach_get_cmos_time(); + retval = get_wallclock(); spin_unlock_irqrestore(&rtc_lock, flags); @@ -370,7 +365,7 @@ static void __init hpet_time_init(void) printk("Using HPET for base-timer\n"); } - time_init_hook(); + do_time_init(); } #endif @@ -392,5 +387,5 @@ void __init time_init(void) do_settimeofday(&ts); - time_init_hook(); + do_time_init(); } diff --git a/arch/i386/power/cpu.c b/arch/i386/power/cpu.c index 5a1abeff033..2c15500f871 100644 --- a/arch/i386/power/cpu.c +++ b/arch/i386/power/cpu.c @@ -26,8 +26,8 @@ void __save_processor_state(struct saved_context *ctxt) /* * descriptor tables */ - store_gdt(&ctxt->gdt_limit); - store_idt(&ctxt->idt_limit); + store_gdt(&ctxt->gdt); + store_idt(&ctxt->idt); store_tr(ctxt->tr); /* @@ -99,8 +99,8 @@ void __restore_processor_state(struct saved_context *ctxt) * now restore the descriptor tables to their proper values * ltr is done i fix_processor_context(). */ - load_gdt(&ctxt->gdt_limit); - load_idt(&ctxt->idt_limit); + load_gdt(&ctxt->gdt); + load_idt(&ctxt->idt); /* * segment registers -- cgit v1.2.3-70-g09d2