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| author | Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> | 2010-07-16 03:25:17 (GMT) |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2010-08-02 03:40:58 (GMT) |
| commit | 9ed5520dd3c9cb79c25f95fce9c57b87637d0fb7 (patch) | |
| tree | 32a983f23b3aa4dba5dea64a57f1b96126afe92a /arch/x86/kvm | |
| parent | daa3db693ce925a14b7e17ab6f306dc0e6a5342c (diff) | |
| download | linux-9ed5520dd3c9cb79c25f95fce9c57b87637d0fb7.tar.xz | |
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>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/mmu.c | 10 |
1 files changed, 3 insertions, 7 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 9b3b916..a04756a 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; |