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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>
This commit is contained in:
Izik Eidus 2008-03-20 18:17:24 +02:00 committed by Avi Kivity
parent 69a9f69bb2
commit 855149aaa9
1 changed files with 8 additions and 0 deletions
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8
arch/x86/kvm/mmu.c
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@ -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);