forked from Minki/linux
KVM: MMU: fix page dirty tracking lost while sync page
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 <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Avi Kivity <avi@redhat.com>
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@ -1985,6 +1985,8 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
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mark_page_dirty(vcpu->kvm, gfn);
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set_pte:
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if (is_writable_pte(*sptep) && !is_writable_pte(spte))
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kvm_set_pfn_dirty(pfn);
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update_spte(sptep, spte);
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done:
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return ret;
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@ -1998,7 +2000,6 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
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bool reset_host_protection)
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{
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int was_rmapped = 0;
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int was_writable = is_writable_pte(*sptep);
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int rmap_count;
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pgprintk("%s: spte %llx access %x write_fault %d"
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@ -2048,15 +2049,10 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
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page_header_update_slot(vcpu->kvm, sptep, gfn);
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if (!was_rmapped) {
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rmap_count = rmap_add(vcpu, sptep, gfn);
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kvm_release_pfn_clean(pfn);
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if (rmap_count > RMAP_RECYCLE_THRESHOLD)
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rmap_recycle(vcpu, sptep, gfn);
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} else {
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if (was_writable)
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kvm_release_pfn_dirty(pfn);
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else
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kvm_release_pfn_clean(pfn);
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}
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kvm_release_pfn_clean(pfn);
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if (speculative) {
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vcpu->arch.last_pte_updated = sptep;
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vcpu->arch.last_pte_gfn = gfn;
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