KVM: MMU: mark page table dirty when a pte is actually modified
Sometime cmpxchg_gpte doesn't modify gpte, in such case, don't mark
page table page as dirty.
Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index c7f2777..5c8ac06 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -177,10 +177,10 @@
if (!(pte & PT_ACCESSED_MASK)) {
trace_kvm_mmu_set_accessed_bit(table_gfn, index,
sizeof(pte));
- mark_page_dirty(vcpu->kvm, table_gfn);
if (FNAME(cmpxchg_gpte)(vcpu->kvm, table_gfn,
index, pte, pte|PT_ACCESSED_MASK))
goto walk;
+ mark_page_dirty(vcpu->kvm, table_gfn);
pte |= PT_ACCESSED_MASK;
}
@@ -217,11 +217,11 @@
bool ret;
trace_kvm_mmu_set_dirty_bit(table_gfn, index, sizeof(pte));
- mark_page_dirty(vcpu->kvm, table_gfn);
ret = FNAME(cmpxchg_gpte)(vcpu->kvm, table_gfn, index, pte,
pte|PT_DIRTY_MASK);
if (ret)
goto walk;
+ mark_page_dirty(vcpu->kvm, table_gfn);
pte |= PT_DIRTY_MASK;
walker->ptes[walker->level - 1] = pte;
}