[PATCH] fixing dirty bit setting for calls of rmap_write_protect

[PATCH] fixing dirty bit setting for calls of rmap_write_protect

[Izik Eidus]

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-- 
woof.


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>From 8a849eb0cedacb384676aa7416e8997d89fe9b0f Mon Sep 17 00:00:00 2001
From: Izik Eidus <izike@qumranet.com>
Date: Tue, 12 Feb 2008 17:56:43 +0200
Subject: [PATCH] KVM: mmu: fixing dirty bit setting for calls of rmap_write_protect

when mmu_set_spte is checking 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 get
called it is possible for shadow ptes that were writeble to become readonly
and therefor mmu_set_spte will release the pages of the sptes as clean
and not as dirty.
this patch fix this issue by marking the page as dirty inside rmap_write_protect

Signed-off-by: Izik Eidus <izike@qumranet.com>
---
 arch/x86/kvm/mmu.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 635e70c..83136f2 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -520,8 +520,14 @@ static void rmap_write_protect(struct kvm *kvm, u64 gfn)
 		}
 		spte = rmap_next(kvm, rmapp, spte);
 	}
-	if (write_protected)
+	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);
 		kvm_flush_remote_tlbs(kvm);
+	}
 }
 
 #ifdef MMU_DEBUG
-- 
1.5.3.6


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