From be38d276b0189fa86231fc311428622a1981ad62 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Sun, 6 Jun 2010 14:31:27 +0300 Subject: KVM: MMU: Introduce drop_spte() When we call rmap_remove(), we (almost) always immediately follow it by an __set_spte() to a nonpresent pte. Since we need to perform the two operations atomically, to avoid losing the dirty and accessed bits, introduce a helper drop_spte() and convert all call sites. The operation is still nonatomic at this point. Signed-off-by: Avi Kivity --- arch/x86/kvm/paging_tmpl.h | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) (limited to 'arch/x86/kvm/paging_tmpl.h') diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 59e750c..796a325 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -353,8 +353,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, } if (is_large_pte(*sptep)) { - rmap_remove(vcpu->kvm, sptep); - __set_spte(sptep, shadow_trap_nonpresent_pte); + drop_spte(vcpu->kvm, sptep, shadow_trap_nonpresent_pte); kvm_flush_remote_tlbs(vcpu->kvm); } @@ -516,12 +515,13 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva) pte_gpa += (sptep - sp->spt) * sizeof(pt_element_t); if (is_shadow_present_pte(*sptep)) { - rmap_remove(vcpu->kvm, sptep); if (is_large_pte(*sptep)) --vcpu->kvm->stat.lpages; + drop_spte(vcpu->kvm, sptep, + shadow_trap_nonpresent_pte); need_flush = 1; - } - __set_spte(sptep, shadow_trap_nonpresent_pte); + } else + __set_spte(sptep, shadow_trap_nonpresent_pte); break; } @@ -637,12 +637,11 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, !is_present_gpte(gpte) || !(gpte & PT_ACCESSED_MASK)) { u64 nonpresent; - rmap_remove(vcpu->kvm, &sp->spt[i]); if (is_present_gpte(gpte) || !clear_unsync) nonpresent = shadow_trap_nonpresent_pte; else nonpresent = shadow_notrap_nonpresent_pte; - __set_spte(&sp->spt[i], nonpresent); + drop_spte(vcpu->kvm, &sp->spt[i], nonpresent); continue; } -- cgit v1.1