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

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>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 863baf70506e..641c07844e6e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1269,6 +1269,8 @@ 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;
         }