From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Mon, 23 Mar 2009 20:51:32 +0000 (-0300)
Subject: KVM: MMU: check for present pdptr shadow page in walk_shadow
X-Git-Tag: v2.6.28.10~20
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3899af53551a9d5f0b316b9b5d1afba2ac47d0a9;p=thirdparty%2Fkernel%2Fstable.git

KVM: MMU: check for present pdptr shadow page in walk_shadow

(cherry picked from eb64f1e8cd5c3cae912db30a77d062367f7a11a6)

walk_shadow assumes the caller verified validity of the pdptr pointer in
question, which is not the case for the invlpg handler.

Fixes oops during Solaris 10 install.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 47c5d3a47f966..0d2918632b88d 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1159,6 +1159,8 @@ static int walk_shadow(struct kvm_shadow_walk *walker,
 	if (level == PT32E_ROOT_LEVEL) {
 		shadow_addr = vcpu->arch.mmu.pae_root[(addr >> 30) & 3];
 		shadow_addr &= PT64_BASE_ADDR_MASK;
+		if (!shadow_addr)
+			return 1;
 		--level;
 	}