[89/98] KVM: MMU: bail out pagewalk on kvm_read_guest error
From: Greg KH
Date: Tue Jan 26 2010 - 18:48:11 EST
2.6.32-stable review patch. If anyone has any objections, please let us know.
------------------
From: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
commit a6085fbaf65ab09bfb5ec8d902d6d21680fe1895 upstream.
Exit the guest pagetable walk loop if reading gpte failed. Otherwise its
possible to enter an endless loop processing the previous present pte.
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
arch/x86/kvm/paging_tmpl.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -150,7 +150,9 @@ walk:
walker->table_gfn[walker->level - 1] = table_gfn;
walker->pte_gpa[walker->level - 1] = pte_gpa;
- kvm_read_guest(vcpu->kvm, pte_gpa, &pte, sizeof(pte));
+ if (kvm_read_guest(vcpu->kvm, pte_gpa, &pte, sizeof(pte)))
+ goto not_present;
+
trace_kvm_mmu_paging_element(pte, walker->level);
if (!is_present_gpte(pte))
--
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