[patch 159/164] KVM: SVM: Dont allow nested guest to VMMCALL into host

Greg KH
2010-07-01T20:57:37Z

2.6.33-stable review patch. If anyone has any objections, please let me know.

------------------

From: Joerg Roedel <joerg.roedel@amd.com>

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
(cherry picked from commit 0d945bd9351199744c1e89d57a70615b6ee9f394)
---
arch/x86/kvm/svm.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1829,8 +1829,13 @@ static bool nested_svm_vmrun(struct vcpu
svm->vmcb->control.intercept_cr_write &= ~INTERCEPT_CR8_MASK;
}

- /* We don't want a nested guest to be more powerful than the guest,
- so all intercepts are ORed */
+ /* 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
+ */
svm->vmcb->control.intercept_cr_read |=
nested_vmcb->control.intercept_cr_read;
svm->vmcb->control.intercept_cr_write |=