From: Xiao Guangrong <[email protected]> In sync-page path, if spte.writable is changed, it will lose page dirty tracking, for example:
assume spte.writable = 0 in a unsync-page, when it's synced, it map spte to writable(that is spte.writable = 1), later guest write spte.gfn, it means spte.gfn is dirty, then guest changed this mapping to read-only, after it's synced, spte.writable = 0 So, when host release the spte, it detect spte.writable = 0 and not mark page dirty Signed-off-by: Xiao Guangrong <[email protected]> Signed-off-by: Avi Kivity <[email protected]> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 27955cf..a224a0b 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1985,6 +1985,8 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, mark_page_dirty(vcpu->kvm, gfn); set_pte: + if (is_writable_pte(*sptep) && !is_writable_pte(spte)) + kvm_set_pfn_dirty(pfn); update_spte(sptep, spte); done: return ret; @@ -1998,7 +2000,6 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, bool reset_host_protection) { int was_rmapped = 0; - int was_writable = is_writable_pte(*sptep); int rmap_count; pgprintk("%s: spte %llx access %x write_fault %d" @@ -2048,15 +2049,10 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, page_header_update_slot(vcpu->kvm, sptep, gfn); if (!was_rmapped) { rmap_count = rmap_add(vcpu, sptep, gfn); - kvm_release_pfn_clean(pfn); if (rmap_count > RMAP_RECYCLE_THRESHOLD) rmap_recycle(vcpu, sptep, gfn); - } else { - if (was_writable) - kvm_release_pfn_dirty(pfn); - else - kvm_release_pfn_clean(pfn); } + kvm_release_pfn_clean(pfn); if (speculative) { vcpu->arch.last_pte_updated = sptep; vcpu->arch.last_pte_gfn = gfn; -- To unsubscribe from this list: send the line "unsubscribe kvm-commits" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
