Move the code to validate an indirect shadow page (by verifying that the gpte has not changed since it was fetched) into a helper.
Signed-off-by: Avi Kivity <[email protected]> --- arch/x86/kvm/paging_tmpl.h | 29 ++++++++++++++++++++--------- 1 files changed, 20 insertions(+), 9 deletions(-) diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index cacb4f2..72f54fe 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -299,6 +299,23 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, gpte_to_gfn(gpte), pfn, true, true); } +static bool FNAME(validate_indirect_spte)(struct kvm_vcpu *vcpu, + u64 *sptep, struct kvm_mmu_page *sp, + struct guest_walker *gw, int level) +{ + int r; + pt_element_t curr_pte; + + 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]) { + kvm_mmu_put_page(sp, sptep); + return false; + } + return true; +} + /* * Fetch a shadow pte for a specific level in the paging hierarchy. */ @@ -312,11 +329,9 @@ 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])) @@ -364,17 +379,13 @@ 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]) { - kvm_mmu_put_page(sp, sptep); + if (!direct) + if (!FNAME(validate_indirect_spte)(vcpu, sptep, sp, + gw, level)) { kvm_release_pfn_clean(pfn); sptep = NULL; break; } - } link_shadow_page(sptep, sp); } -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
