KVM: MMU: fix dirty bit setting when removing write permissions
When mmu_set_spte() checks if a page related to spte should be release as
dirty or clean, it check if the shadow pte was writeble, but in case
rmap_write_protect() is called called it is possible for shadow ptes that were
writeble to become readonly and therefor mmu_set_spte will release the pages
as clean.
This patch fix this issue by marking the page as dirty inside
rmap_write_protect().
Signed-off-by: Izik Eidus <izike@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a5872b3..dd4b95b 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -626,6 +626,14 @@
}
spte = rmap_next(kvm, rmapp, spte);
}
+ if (write_protected) {
+ struct page *page;
+
+ spte = rmap_next(kvm, rmapp, NULL);
+ page = pfn_to_page((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT);
+ SetPageDirty(page);
+ }
+
/* check for huge page mappings */
rmapp = gfn_to_rmap(kvm, gfn, 1);
spte = rmap_next(kvm, rmapp, NULL);
