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authorMarcelo Tosatti <marcelo@kvack.org>2008-03-17 10:08:18 -0300
committerAvi Kivity <avi@qumranet.com>2008-03-25 10:22:17 +0200
commit15aaa819e20cb183f26392ed8ea16020630ef142 (patch)
tree28f7aa56ee06f60030384f2de99d10449d6e5ed8 /arch/x86/kvm
parent4b1a80fa65aa9e2ec5696998856136c886385538 (diff)
downloadlinux-15aaa819e20cb183f26392ed8ea16020630ef142.tar.gz
KVM: MMU: handle page removal with shadow mapping
Do not assume that a shadow mapping will always point to the same host
frame number.  Fixes crash with madvise(MADV_DONTNEED).

[avi: move after first printk(), add another printk()]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/mmu.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index e49c4d433c0f..4ba85d95bd29 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -892,14 +892,25 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
 			 int *ptwrite, gfn_t gfn, struct page *page)
 {
 	u64 spte;
-	int was_rmapped = is_rmap_pte(*shadow_pte);
+	int was_rmapped = 0;
 	int was_writeble = is_writeble_pte(*shadow_pte);
+	hfn_t host_pfn = (*shadow_pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
 
 	pgprintk("%s: spte %llx access %x write_fault %d"
 		 " user_fault %d gfn %lx\n",
 		 __FUNCTION__, *shadow_pte, pt_access,
 		 write_fault, user_fault, gfn);
 
+	if (is_rmap_pte(*shadow_pte)) {
+		if (host_pfn != page_to_pfn(page)) {
+			pgprintk("hfn old %lx new %lx\n",
+				 host_pfn, page_to_pfn(page));
+			rmap_remove(vcpu->kvm, shadow_pte);
+		}
+		else
+			was_rmapped = 1;
+	}
+
 	/*
 	 * We don't set the accessed bit, since we sometimes want to see
 	 * whether the guest actually used the pte (in order to detect