diff options
Diffstat (limited to 'drivers/kvm/mmu.c')
| -rw-r--r-- | drivers/kvm/mmu.c | 699 |
1 files changed, 699 insertions, 0 deletions
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c new file mode 100644 index 00000000000..4e29d9b7211 --- /dev/null +++ b/drivers/kvm/mmu.c @@ -0,0 +1,699 @@ +/* + * Kernel-based Virtual Machine driver for Linux + * + * This module enables machines with Intel VT-x extensions to run virtual + * machines without emulation or binary translation. + * + * MMU support + * + * Copyright (C) 2006 Qumranet, Inc. + * + * Authors: + * Yaniv Kamay <yaniv@qumranet.com> + * Avi Kivity <avi@qumranet.com> + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + * + */ +#include <linux/types.h> +#include <linux/string.h> +#include <asm/page.h> +#include <linux/mm.h> +#include <linux/highmem.h> +#include <linux/module.h> + +#include "vmx.h" +#include "kvm.h" + +#define pgprintk(x...) do { } while (0) + +#define ASSERT(x) \ + if (!(x)) { \ + printk(KERN_WARNING "assertion failed %s:%d: %s\n", \ + __FILE__, __LINE__, #x); \ + } + +#define PT64_ENT_PER_PAGE 512 +#define PT32_ENT_PER_PAGE 1024 + +#define PT_WRITABLE_SHIFT 1 + +#define PT_PRESENT_MASK (1ULL << 0) +#define PT_WRITABLE_MASK (1ULL << PT_WRITABLE_SHIFT) +#define PT_USER_MASK (1ULL << 2) +#define PT_PWT_MASK (1ULL << 3) +#define PT_PCD_MASK (1ULL << 4) +#define PT_ACCESSED_MASK (1ULL << 5) +#define PT_DIRTY_MASK (1ULL << 6) +#define PT_PAGE_SIZE_MASK (1ULL << 7) +#define PT_PAT_MASK (1ULL << 7) +#define PT_GLOBAL_MASK (1ULL << 8) +#define PT64_NX_MASK (1ULL << 63) + +#define PT_PAT_SHIFT 7 +#define PT_DIR_PAT_SHIFT 12 +#define PT_DIR_PAT_MASK (1ULL << PT_DIR_PAT_SHIFT) + +#define PT32_DIR_PSE36_SIZE 4 +#define PT32_DIR_PSE36_SHIFT 13 +#define PT32_DIR_PSE36_MASK (((1ULL << PT32_DIR_PSE36_SIZE) - 1) << PT32_DIR_PSE36_SHIFT) + + +#define PT32_PTE_COPY_MASK \ + (PT_PRESENT_MASK | PT_PWT_MASK | PT_PCD_MASK | \ + PT_ACCESSED_MASK | PT_DIRTY_MASK | PT_PAT_MASK | \ + PT_GLOBAL_MASK ) + +#define PT32_NON_PTE_COPY_MASK \ + (PT_PRESENT_MASK | PT_PWT_MASK | PT_PCD_MASK | \ + PT_ACCESSED_MASK | PT_DIRTY_MASK) + + +#define PT64_PTE_COPY_MASK \ + (PT64_NX_MASK | PT32_PTE_COPY_MASK) + +#define PT64_NON_PTE_COPY_MASK \ + (PT64_NX_MASK | PT32_NON_PTE_COPY_MASK) + + + +#define PT_FIRST_AVAIL_BITS_SHIFT 9 +#define PT64_SECOND_AVAIL_BITS_SHIFT 52 + +#define PT_SHADOW_PS_MARK (1ULL << PT_FIRST_AVAIL_BITS_SHIFT) +#define PT_SHADOW_IO_MARK (1ULL << PT_FIRST_AVAIL_BITS_SHIFT) + +#define PT_SHADOW_WRITABLE_SHIFT (PT_FIRST_AVAIL_BITS_SHIFT + 1) +#define PT_SHADOW_WRITABLE_MASK (1ULL << PT_SHADOW_WRITABLE_SHIFT) + +#define PT_SHADOW_USER_SHIFT (PT_SHADOW_WRITABLE_SHIFT + 1) +#define PT_SHADOW_USER_MASK (1ULL << (PT_SHADOW_USER_SHIFT)) + +#define PT_SHADOW_BITS_OFFSET (PT_SHADOW_WRITABLE_SHIFT - PT_WRITABLE_SHIFT) + +#define VALID_PAGE(x) ((x) != INVALID_PAGE) + +#define PT64_LEVEL_BITS 9 + +#define PT64_LEVEL_SHIFT(level) \ + ( PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS ) + +#define PT64_LEVEL_MASK(level) \ + (((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level)) + +#define PT64_INDEX(address, level)\ + (((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1)) + + +#define PT32_LEVEL_BITS 10 + +#define PT32_LEVEL_SHIFT(level) \ + ( PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS ) + +#define PT32_LEVEL_MASK(level) \ + (((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level)) + +#define PT32_INDEX(address, level)\ + (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1)) + + +#define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & PAGE_MASK) +#define PT64_DIR_BASE_ADDR_MASK \ + (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1)) + +#define PT32_BASE_ADDR_MASK PAGE_MASK +#define PT32_DIR_BASE_ADDR_MASK \ + (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1)) + + +#define PFERR_PRESENT_MASK (1U << 0) +#define PFERR_WRITE_MASK (1U << 1) +#define PFERR_USER_MASK (1U << 2) + +#define PT64_ROOT_LEVEL 4 +#define PT32_ROOT_LEVEL 2 +#define PT32E_ROOT_LEVEL 3 + +#define PT_DIRECTORY_LEVEL 2 +#define PT_PAGE_TABLE_LEVEL 1 + +static int is_write_protection(struct kvm_vcpu *vcpu) +{ + return vcpu->cr0 & CR0_WP_MASK; +} + +static int is_cpuid_PSE36(void) +{ + return 1; +} + +static int is_present_pte(unsigned long pte) +{ + return pte & PT_PRESENT_MASK; +} + +static int is_writeble_pte(unsigned long pte) +{ + return pte & PT_WRITABLE_MASK; +} + +static int is_io_pte(unsigned long pte) +{ + return pte & PT_SHADOW_IO_MARK; +} + +static void kvm_mmu_free_page(struct kvm_vcpu *vcpu, hpa_t page_hpa) +{ + struct kvm_mmu_page *page_head = page_header(page_hpa); + + list_del(&page_head->link); + page_head->page_hpa = page_hpa; + list_add(&page_head->link, &vcpu->free_pages); +} + +static int is_empty_shadow_page(hpa_t page_hpa) +{ + u32 *pos; + u32 *end; + for (pos = __va(page_hpa), end = pos + PAGE_SIZE / sizeof(u32); + pos != end; pos++) + if (*pos != 0) + return 0; + return 1; +} + +static hpa_t kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, u64 *parent_pte) +{ + struct kvm_mmu_page *page; + + if (list_empty(&vcpu->free_pages)) + return INVALID_PAGE; + + page = list_entry(vcpu->free_pages.next, struct kvm_mmu_page, link); + list_del(&page->link); + list_add(&page->link, &vcpu->kvm->active_mmu_pages); + ASSERT(is_empty_shadow_page(page->page_hpa)); + page->slot_bitmap = 0; + page->global = 1; + page->parent_pte = parent_pte; + return page->page_hpa; +} + +static void page_header_update_slot(struct kvm *kvm, void *pte, gpa_t gpa) +{ + int slot = memslot_id(kvm, gfn_to_memslot(kvm, gpa >> PAGE_SHIFT)); + struct kvm_mmu_page *page_head = page_header(__pa(pte)); + + __set_bit(slot, &page_head->slot_bitmap); +} + +hpa_t safe_gpa_to_hpa(struct kvm_vcpu *vcpu, gpa_t gpa) +{ + hpa_t hpa = gpa_to_hpa(vcpu, gpa); + + return is_error_hpa(hpa) ? bad_page_address | (gpa & ~PAGE_MASK): hpa; +} + +hpa_t gpa_to_hpa(struct kvm_vcpu *vcpu, gpa_t gpa) +{ + struct kvm_memory_slot *slot; + struct page *page; + + ASSERT((gpa & HPA_ERR_MASK) == 0); + slot = gfn_to_memslot(vcpu->kvm, gpa >> PAGE_SHIFT); + if (!slot) + return gpa | HPA_ERR_MASK; + page = gfn_to_page(slot, gpa >> PAGE_SHIFT); + return ((hpa_t)page_to_pfn(page) << PAGE_SHIFT) + | (gpa & (PAGE_SIZE-1)); +} + +hpa_t gva_to_hpa(struct kvm_vcpu *vcpu, gva_t gva) +{ + gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva); + + if (gpa == UNMAPPED_GVA) + return UNMAPPED_GVA; + return gpa_to_hpa(vcpu, gpa); +} + + +static void release_pt_page_64(struct kvm_vcpu *vcpu, hpa_t page_hpa, + int level) +{ + ASSERT(vcpu); + ASSERT(VALID_PAGE(page_hpa)); + ASSERT(level <= PT64_ROOT_LEVEL && level > 0); + + if (level == 1) + memset(__va(page_hpa), 0, PAGE_SIZE); + else { + u64 *pos; + u64 *end; + + for (pos = __va(page_hpa), end = pos + PT64_ENT_PER_PAGE; + pos != end; pos++) { + u64 current_ent = *pos; + + *pos = 0; + if (is_present_pte(current_ent)) + release_pt_page_64(vcpu, + current_ent & + PT64_BASE_ADDR_MASK, + level - 1); + } + } + kvm_mmu_free_page(vcpu, page_hpa); +} + +static void nonpaging_new_cr3(struct kvm_vcpu *vcpu) +{ +} + +static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, hpa_t p) +{ + int level = PT32E_ROOT_LEVEL; + hpa_t table_addr = vcpu->mmu.root_hpa; + + for (; ; level--) { + u32 index = PT64_INDEX(v, level); + u64 *table; + + ASSERT(VALID_PAGE(table_addr)); + table = __va(table_addr); + + if (level == 1) { + mark_page_dirty(vcpu->kvm, v >> PAGE_SHIFT); + page_header_update_slot(vcpu->kvm, table, v); + table[index] = p | PT_PRESENT_MASK | PT_WRITABLE_MASK | + PT_USER_MASK; + return 0; + } + + if (table[index] == 0) { + hpa_t new_table = kvm_mmu_alloc_page(vcpu, + &table[index]); + + if (!VALID_PAGE(new_table)) { + pgprintk("nonpaging_map: ENOMEM\n"); + return -ENOMEM; + } + + if (level == PT32E_ROOT_LEVEL) + table[index] = new_table | PT_PRESENT_MASK; + else + table[index] = new_table | PT_PRESENT_MASK | + PT_WRITABLE_MASK | PT_USER_MASK; + } + table_addr = table[index] & PT64_BASE_ADDR_MASK; + } +} + +static void nonpaging_flush(struct kvm_vcpu *vcpu) +{ + hpa_t root = vcpu->mmu.root_hpa; + + ++kvm_stat.tlb_flush; + pgprintk("nonpaging_flush\n"); + ASSERT(VALID_PAGE(root)); + release_pt_page_64(vcpu, root, vcpu->mmu.shadow_root_level); + root = kvm_mmu_alloc_page(vcpu, NULL); + ASSERT(VALID_PAGE(root)); + vcpu->mmu.root_hpa = root; + if (is_paging(vcpu)) + root |= (vcpu->cr3 & (CR3_PCD_MASK | CR3_WPT_MASK)); + kvm_arch_ops->set_cr3(vcpu, root); + kvm_arch_ops->tlb_flush(vcpu); +} + +static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr) +{ + return vaddr; +} + +static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva, + u32 error_code) +{ + int ret; + gpa_t addr = gva; + + ASSERT(vcpu); + ASSERT(VALID_PAGE(vcpu->mmu.root_hpa)); + + for (;;) { + hpa_t paddr; + + paddr = gpa_to_hpa(vcpu , addr & PT64_BASE_ADDR_MASK); + + if (is_error_hpa(paddr)) + return 1; + + ret = nonpaging_map(vcpu, addr & PAGE_MASK, paddr); + if (ret) { + nonpaging_flush(vcpu); + continue; + } + break; + } + return ret; +} + +static void nonpaging_inval_page(struct kvm_vcpu *vcpu, gva_t addr) +{ +} + +static void nonpaging_free(struct kvm_vcpu *vcpu) +{ + hpa_t root; + + ASSERT(vcpu); + root = vcpu->mmu.root_hpa; + if (VALID_PAGE(root)) + release_pt_page_64(vcpu, root, vcpu->mmu.shadow_root_level); + vcpu->mmu.root_hpa = INVALID_PAGE; +} + +static int nonpaging_init_context(struct kvm_vcpu *vcpu) +{ + struct kvm_mmu *context = &vcpu->mmu; + + context->new_cr3 = nonpaging_new_cr3; + context->page_fault = nonpaging_page_fault; + context->inval_page = nonpaging_inval_page; + context->gva_to_gpa = nonpaging_gva_to_gpa; + context->free = nonpaging_free; + context->root_level = PT32E_ROOT_LEVEL; + context->shadow_root_level = PT32E_ROOT_LEVEL; + context->root_hpa = kvm_mmu_alloc_page(vcpu, NULL); + ASSERT(VALID_PAGE(context->root_hpa)); + kvm_arch_ops->set_cr3(vcpu, context->root_hpa); + return 0; +} + + +static void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu) +{ + struct kvm_mmu_page *page, *npage; + + list_for_each_entry_safe(page, npage, &vcpu->kvm->active_mmu_pages, + link) { + if (page->global) + continue; + + if (!page->parent_pte) + continue; + + *page->parent_pte = 0; + release_pt_page_64(vcpu, page->page_hpa, 1); + } + ++kvm_stat.tlb_flush; + kvm_arch_ops->tlb_flush(vcpu); +} + +static void paging_new_cr3(struct kvm_vcpu *vcpu) +{ + kvm_mmu_flush_tlb(vcpu); +} + +static void mark_pagetable_nonglobal(void *shadow_pte) +{ + page_header(__pa(shadow_pte))->global = 0; +} + +static inline void set_pte_common(struct kvm_vcpu *vcpu, + u64 *shadow_pte, + gpa_t gaddr, + int dirty, + u64 access_bits) +{ + hpa_t paddr; + + *shadow_pte |= access_bits << PT_SHADOW_BITS_OFFSET; + if (!dirty) + access_bits &= ~PT_WRITABLE_MASK; + + if (access_bits & PT_WRITABLE_MASK) + mark_page_dirty(vcpu->kvm, gaddr >> PAGE_SHIFT); + + *shadow_pte |= access_bits; + + paddr = gpa_to_hpa(vcpu, gaddr & PT64_BASE_ADDR_MASK); + + if (!(*shadow_pte & PT_GLOBAL_MASK)) + mark_pagetable_nonglobal(shadow_pte); + + if (is_error_hpa(paddr)) { + *shadow_pte |= gaddr; + *shadow_pte |= PT_SHADOW_IO_MARK; + *shadow_pte &= ~PT_PRESENT_MASK; + } else { + *shadow_pte |= paddr; + page_header_update_slot(vcpu->kvm, shadow_pte, gaddr); + } +} + +static void inject_page_fault(struct kvm_vcpu *vcpu, + u64 addr, + u32 err_code) +{ + kvm_arch_ops->inject_page_fault(vcpu, addr, err_code); +} + +static inline int fix_read_pf(u64 *shadow_ent) +{ + if ((*shadow_ent & PT_SHADOW_USER_MASK) && + !(*shadow_ent & PT_USER_MASK)) { + /* + * If supervisor write protect is disabled, we shadow kernel + * pages as user pages so we can trap the write access. + */ + *shadow_ent |= PT_USER_MASK; + *shadow_ent &= ~PT_WRITABLE_MASK; + + return 1; + + } + return 0; +} + +static int may_access(u64 pte, int write, int user) +{ + + if (user && !(pte & PT_USER_MASK)) + return 0; + if (write && !(pte & PT_WRITABLE_MASK)) + return 0; + return 1; +} + +/* + * Remove a shadow pte. + */ +static void paging_inval_page(struct kvm_vcpu *vcpu, gva_t addr) +{ + hpa_t page_addr = vcpu->mmu.root_hpa; + int level = vcpu->mmu.shadow_root_level; + + ++kvm_stat.invlpg; + + for (; ; level--) { + u32 index = PT64_INDEX(addr, level); + u64 *table = __va(page_addr); + + if (level == PT_PAGE_TABLE_LEVEL ) { + table[index] = 0; + return; + } + + if (!is_present_pte(table[index])) + return; + + page_addr = table[index] & PT64_BASE_ADDR_MASK; + + if (level == PT_DIRECTORY_LEVEL && + (table[index] & PT_SHADOW_PS_MARK)) { + table[index] = 0; + release_pt_page_64(vcpu, page_addr, PT_PAGE_TABLE_LEVEL); + + kvm_arch_ops->tlb_flush(vcpu); + return; + } + } +} + +static void paging_free(struct kvm_vcpu *vcpu) +{ + nonpaging_free(vcpu); +} + +#define PTTYPE 64 +#include "paging_tmpl.h" +#undef PTTYPE + +#define PTTYPE 32 +#include "paging_tmpl.h" +#undef PTTYPE + +static int paging64_init_context(struct kvm_vcpu *vcpu) +{ + struct kvm_mmu *context = &vcpu->mmu; + + ASSERT(is_pae(vcpu)); + context->new_cr3 = paging_new_cr3; + context->page_fault = paging64_page_fault; + context->inval_page = paging_inval_page; + context->gva_to_gpa = paging64_gva_to_gpa; + context->free = paging_free; + context->root_level = PT64_ROOT_LEVEL; + context->shadow_root_level = PT64_ROOT_LEVEL; + context->root_hpa = kvm_mmu_alloc_page(vcpu, NULL); + ASSERT(VALID_PAGE(context->root_hpa)); + kvm_arch_ops->set_cr3(vcpu, context->root_hpa | + (vcpu->cr3 & (CR3_PCD_MASK | CR3_WPT_MASK))); + return 0; +} + +static int paging32_init_context(struct kvm_vcpu *vcpu) +{ + struct kvm_mmu *context = &vcpu->mmu; + + context->new_cr3 = paging_new_cr3; + context->page_fault = paging32_page_fault; + context->inval_page = paging_inval_page; + context->gva_to_gpa = paging32_gva_to_gpa; + context->free = paging_free; + context->root_level = PT32_ROOT_LEVEL; + context->shadow_root_level = PT32E_ROOT_LEVEL; + context->root_hpa = kvm_mmu_alloc_page(vcpu, NULL); + ASSERT(VALID_PAGE(context->root_hpa)); + kvm_arch_ops->set_cr3(vcpu, context->root_hpa | + (vcpu->cr3 & (CR3_PCD_MASK | CR3_WPT_MASK))); + return 0; +} + +static int paging32E_init_context(struct kvm_vcpu *vcpu) +{ + int ret; + + if ((ret = paging64_init_context(vcpu))) + return ret; + + vcpu->mmu.root_level = PT32E_ROOT_LEVEL; + vcpu->mmu.shadow_root_level = PT32E_ROOT_LEVEL; + return 0; +} + +static int init_kvm_mmu(struct kvm_vcpu *vcpu) +{ + ASSERT(vcpu); + ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa)); + + if (!is_paging(vcpu)) + return nonpaging_init_context(vcpu); + else if (kvm_arch_ops->is_long_mode(vcpu)) + return paging64_init_context(vcpu); + else if (is_pae(vcpu)) + return paging32E_init_context(vcpu); + else + return paging32_init_context(vcpu); +} + +static void destroy_kvm_mmu(struct kvm_vcpu *vcpu) +{ + ASSERT(vcpu); + if (VALID_PAGE(vcpu->mmu.root_hpa)) { + vcpu->mmu.free(vcpu); + vcpu->mmu.root_hpa = INVALID_PAGE; + } +} + +int kvm_mmu_reset_context(struct kvm_vcpu *vcpu) +{ + destroy_kvm_mmu(vcpu); + return init_kvm_mmu(vcpu); +} + +static void free_mmu_pages(struct kvm_vcpu *vcpu) +{ + while (!list_empty(&vcpu->free_pages)) { + struct kvm_mmu_page *page; + + page = list_entry(vcpu->free_pages.next, + struct kvm_mmu_page, link); + list_del(&page->link); + __free_page(pfn_to_page(page->page_hpa >> PAGE_SHIFT)); + page->page_hpa = INVALID_PAGE; + } +} + +static int alloc_mmu_pages(struct kvm_vcpu *vcpu) +{ + int i; + + ASSERT(vcpu); + + for (i = 0; i < KVM_NUM_MMU_PAGES; i++) { + struct page *page; + struct kvm_mmu_page *page_header = &vcpu->page_header_buf[i]; + + INIT_LIST_HEAD(&page_header->link); + if ((page = alloc_page(GFP_KVM_MMU)) == NULL) + goto error_1; + page->private = (unsigned long)page_header; + page_header->page_hpa = (hpa_t)page_to_pfn(page) << PAGE_SHIFT; + memset(__va(page_header->page_hpa), 0, PAGE_SIZE); + list_add(&page_header->link, &vcpu->free_pages); + } + return 0; + +error_1: + free_mmu_pages(vcpu); + return -ENOMEM; +} + +int kvm_mmu_init(struct kvm_vcpu *vcpu) +{ + int r; + + ASSERT(vcpu); + ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa)); + ASSERT(list_empty(&vcpu->free_pages)); + + if ((r = alloc_mmu_pages(vcpu))) + return r; + + if ((r = init_kvm_mmu(vcpu))) { + free_mmu_pages(vcpu); + return r; + } + return 0; +} + +void kvm_mmu_destroy(struct kvm_vcpu *vcpu) +{ + ASSERT(vcpu); + + destroy_kvm_mmu(vcpu); + free_mmu_pages(vcpu); +} + +void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot) +{ + struct kvm_mmu_page *page; + + list_for_each_entry(page, &kvm->active_mmu_pages, link) { + int i; + u64 *pt; + + if (!test_bit(slot, &page->slot_bitmap)) + continue; + + pt = __va(page->page_hpa); + for (i = 0; i < PT64_ENT_PER_PAGE; ++i) + /* avoid RMW */ + if (pt[i] & PT_WRITABLE_MASK) + pt[i] &= ~PT_WRITABLE_MASK; + + } +} |