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authorIngo Molnar <mingo@elte.hu>2007-01-06 03:36:59 +0300
committerLinus Torvalds <torvalds@woody.osdl.org>2007-01-06 10:55:28 +0300
commitd21225ee2b6fa9f7669526927f2e0bedebd90940 (patch)
treec606fa6b98a7f30215bb8702fd5e22d1d4123589
parent760db773fbd0ad2ece89393218c4a4213b5bae6a (diff)
downloadlinux-sunxi-d21225ee2b6fa9f7669526927f2e0bedebd90940.tar.xz
[PATCH] KVM: Make loading cr3 more robust
Prevent the guest's loading of a corrupt cr3 (pointing at no guest phsyical page) from crashing the host. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Avi Kivity <avi@qumranet.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--drivers/kvm/kvm_main.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 0675d3e51692..67c1154960f0 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -463,7 +463,19 @@ void set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
vcpu->cr3 = cr3;
spin_lock(&vcpu->kvm->lock);
- vcpu->mmu.new_cr3(vcpu);
+ /*
+ * Does the new cr3 value map to physical memory? (Note, we
+ * catch an invalid cr3 even in real-mode, because it would
+ * cause trouble later on when we turn on paging anyway.)
+ *
+ * A real CPU would silently accept an invalid cr3 and would
+ * attempt to use it - with largely undefined (and often hard
+ * to debug) behavior on the guest side.
+ */
+ if (unlikely(!gfn_to_memslot(vcpu->kvm, cr3 >> PAGE_SHIFT)))
+ inject_gp(vcpu);
+ else
+ vcpu->mmu.new_cr3(vcpu);
spin_unlock(&vcpu->kvm->lock);
}
EXPORT_SYMBOL_GPL(set_cr3);