From: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
To: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Cc: akpm-3NddpPZAyC0@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: [PATCH 7/9] KVM: Make loading cr3 more robust
Date: Fri, 05 Jan 2007 07:56:45 -0000 [thread overview]
Message-ID: <20070105075645.900B6250048@il.qumranet.com> (raw)
In-Reply-To: <459E02E7.5020407-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
From: Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>
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-X9Un+BFzKDI@public.gmane.org>
Signed-off-by: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
Index: linux-2.6/drivers/kvm/kvm_main.c
===================================================================
--- linux-2.6.orig/drivers/kvm/kvm_main.c
+++ linux-2.6/drivers/kvm/kvm_main.c
@@ -463,7 +463,19 @@ void set_cr3(struct kvm_vcpu *vcpu, unsi
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);
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next prev parent reply other threads:[~2007-01-05 7:56 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-05 7:48 [PATCH 0/9] KVM: Flush out my patch queue Avi Kivity
[not found] ` <459E02E7.5020407-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-01-05 7:50 ` [PATCH 1/9] KVM: Improve reporting of vmwrite errors Avi Kivity
2007-01-05 7:51 ` [PATCH 2/9] KVM: Initialize vcpu->kvm a little earlier Avi Kivity
2007-01-05 7:52 ` [PATCH 3/9] KVM: Avoid oom on cr3 switch Avi Kivity
2007-01-05 7:53 ` [PATCH 4/9] KVM: Add missing 'break' Avi Kivity
2007-01-05 7:54 ` [PATCH 5/9] KVM: Don't set guest cr3 from vmx_vcpu_setup() Avi Kivity
2007-01-05 7:55 ` [PATCH 6/9] KVM: MMU: Add missing dirty bit Avi Kivity
2007-01-05 7:56 ` Avi Kivity [this message]
2007-01-05 7:57 ` [PATCH 8/9] KVM: Simplify mmu_alloc_roots() Avi Kivity
2007-01-05 7:58 ` [PATCH 9/9] KVM: Simplify test for interrupt window Avi Kivity
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