KVM: nSVM: restore clobbered INT_CTL fields after clearing VINTR

Restore the INT_CTL value from the guest's VMCB once we've stopped using
it, so that virtual interrupts can be injected as requested by L1.
V_TPR is up-to-date however, and it can change if the guest writes to CR8,
so keep it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index ec98c59..4122ba8 100644 (file)
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1365,9 +1365,17 @@ static void svm_set_vintr(struct vcpu_svm *svm)
 
 static void svm_clear_vintr(struct vcpu_svm *svm)
 {
+       const u32 mask = V_TPR_MASK | V_GIF_ENABLE_MASK | V_GIF_MASK | V_INTR_MASKING_MASK;
        clr_intercept(svm, INTERCEPT_VINTR);
 
-       svm->vmcb->control.int_ctl &= ~V_IRQ_MASK;
+       /* Drop int_ctl fields related to VINTR injection.  */
+       svm->vmcb->control.int_ctl &= mask;
+       if (is_guest_mode(&svm->vcpu)) {
+               WARN_ON((svm->vmcb->control.int_ctl & V_TPR_MASK) !=
+                       (svm->nested.ctl.int_ctl & V_TPR_MASK));
+               svm->vmcb->control.int_ctl |= svm->nested.ctl.int_ctl & ~mask;
+       }
+
        mark_dirty(svm->vmcb, VMCB_INTR);
 }