diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/paging_tmpl.h | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 0c7461d3a5be..e1c1f9eb1cc1 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -299,6 +299,17 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, gpte_to_gfn(gpte), pfn, true, true); } +static bool FNAME(gpte_changed)(struct kvm_vcpu *vcpu, + struct guest_walker *gw, int level) +{ + int r; + pt_element_t curr_pte; + + r = kvm_read_guest_atomic(vcpu->kvm, gw->pte_gpa[level - 1], + &curr_pte, sizeof(curr_pte)); + return r || curr_pte != gw->ptes[level - 1]; +} + /* * Fetch a shadow pte for a specific level in the paging hierarchy. */ @@ -312,11 +323,9 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, u64 *sptep = NULL; int direct; gfn_t table_gfn; - int r; int level; bool dirty = is_dirty_gpte(gw->ptes[gw->level - 1]); unsigned direct_access; - pt_element_t curr_pte; struct kvm_shadow_walk_iterator iterator; if (!is_present_gpte(gw->ptes[gw->level - 1])) @@ -365,17 +374,17 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, } sp = kvm_mmu_get_page(vcpu, table_gfn, addr, level-1, direct, access, sptep); - if (!direct) { - r = kvm_read_guest_atomic(vcpu->kvm, - gw->pte_gpa[level - 2], - &curr_pte, sizeof(curr_pte)); - if (r || curr_pte != gw->ptes[level - 2]) { + if (!direct) + /* + * Verify that the gpte in the page we've just write + * protected is still there. + */ + if (FNAME(gpte_changed)(vcpu, gw, level - 1)) { kvm_mmu_put_page(sp, sptep); kvm_release_pfn_clean(pfn); sptep = NULL; break; } - } link_shadow_page(sptep, sp); } |