Commit 855149aa authored Mar 20, 2008 by Izik Eidus Committed by Avi Kivity Apr 27, 2008

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>

parent 69a9f69b

arch/x86/kvm/mmu.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -626,6 +626,14 @@ static void rmap_write_protect(struct kvm *kvm, u64 gfn)
		}
		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);