diff options
| -rw-r--r-- | drivers/kvm/paging_tmpl.h | 36 |
1 files changed, 34 insertions, 2 deletions
diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h index 3c40a598ceb8..8086f827120f 100644 --- a/drivers/kvm/paging_tmpl.h +++ b/drivers/kvm/paging_tmpl.h @@ -34,7 +34,9 @@ #define PT_LEVEL_BITS PT64_LEVEL_BITS #ifdef CONFIG_X86_64 #define PT_MAX_FULL_LEVELS 4 + #define CMPXCHG cmpxchg #else + #define CMPXCHG cmpxchg64 #define PT_MAX_FULL_LEVELS 2 #endif #elif PTTYPE == 32 @@ -48,6 +50,7 @@ #define PT_LEVEL_MASK(level) PT32_LEVEL_MASK(level) #define PT_LEVEL_BITS PT32_LEVEL_BITS #define PT_MAX_FULL_LEVELS 2 + #define CMPXCHG cmpxchg #else #error Invalid PTTYPE value #endif @@ -78,6 +81,26 @@ static gfn_t gpte_to_gfn_pde(pt_element_t gpte) return (gpte & PT_DIR_BASE_ADDR_MASK) >> PAGE_SHIFT; } +static bool FNAME(cmpxchg_gpte)(struct kvm *kvm, + gfn_t table_gfn, unsigned index, + pt_element_t orig_pte, pt_element_t new_pte) +{ + pt_element_t ret; + pt_element_t *table; + struct page *page; + + page = gfn_to_page(kvm, table_gfn); + table = kmap_atomic(page, KM_USER0); + + ret = CMPXCHG(&table[index], orig_pte, new_pte); + + kunmap_atomic(table, KM_USER0); + + kvm_release_page_dirty(page); + + return (ret != orig_pte); +} + /* * Fetch a guest pte for a guest virtual address */ @@ -91,6 +114,7 @@ static int FNAME(walk_addr)(struct guest_walker *walker, gpa_t pte_gpa; pgprintk("%s: addr %lx\n", __FUNCTION__, addr); +walk: walker->level = vcpu->mmu.root_level; pte = vcpu->cr3; #if PTTYPE == 64 @@ -135,8 +159,10 @@ static int FNAME(walk_addr)(struct guest_walker *walker, if (!(pte & PT_ACCESSED_MASK)) { mark_page_dirty(vcpu->kvm, table_gfn); + if (FNAME(cmpxchg_gpte)(vcpu->kvm, table_gfn, + index, pte, pte|PT_ACCESSED_MASK)) + goto walk; pte |= PT_ACCESSED_MASK; - kvm_write_guest(vcpu->kvm, pte_gpa, &pte, sizeof(pte)); } if (walker->level == PT_PAGE_TABLE_LEVEL) { @@ -159,9 +185,14 @@ static int FNAME(walk_addr)(struct guest_walker *walker, } if (write_fault && !is_dirty_pte(pte)) { + bool ret; + mark_page_dirty(vcpu->kvm, table_gfn); + ret = FNAME(cmpxchg_gpte)(vcpu->kvm, table_gfn, index, pte, + pte|PT_DIRTY_MASK); + if (ret) + goto walk; pte |= PT_DIRTY_MASK; - kvm_write_guest(vcpu->kvm, pte_gpa, &pte, sizeof(pte)); kvm_mmu_pte_write(vcpu, pte_gpa, (u8 *)&pte, sizeof(pte)); } @@ -484,3 +515,4 @@ static void FNAME(prefetch_page)(struct kvm_vcpu *vcpu, #undef PT_MAX_FULL_LEVELS #undef gpte_to_gfn #undef gpte_to_gfn_pde +#undef CMPXCHG |