From 0d945bd9351199744c1e89d57a70615b6ee9f394 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Wed, 5 May 2010 16:04:45 +0200 Subject: [PATCH] KVM: SVM: Don't allow nested guest to VMMCALL into host 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 Signed-off-by: Avi Kivity --- arch/x86/kvm/svm.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 2511664ff671..4a66ffe1dc87 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -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