KVM: SVM: Don't allow nested guest to VMMCALL into host
authorJoerg Roedel <joerg.roedel@amd.com>
Wed, 5 May 2010 14:04:45 +0000 (16:04 +0200)
committerAvi Kivity <avi@redhat.com>
Wed, 19 May 2010 08:36:38 +0000 (11:36 +0300)
This patch disables the possibility for a l2-guest to do a
VMMCALL directly into the host. This would happen if the
l1-hypervisor doesn't intercept VMMCALL and the l2-guest
executes this instruction.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
arch/x86/kvm/svm.c

index 2511664ff6717ffe34027738b4e693b86df46dee..4a66ffe1dc873672ffd4b8d41c954e23b0a08f1c 100644 (file)
@@ -2036,6 +2036,9 @@ static bool nested_svm_vmrun(struct vcpu_svm *svm)
                svm->vmcb->control.intercept_cr_write &= ~INTERCEPT_CR8_MASK;
        }
 
+       /* We don't want to see VMMCALLs from a nested guest */
+       svm->vmcb->control.intercept &= ~(1ULL << INTERCEPT_VMMCALL);
+
        /*
         * We don't want a nested guest to be more powerful than the guest, so
         * all intercepts are ORed