KVM: Drop interrupt shadow when single stepping should be done only on VMX
authorGleb Natapov <gleb@redhat.com>
Mon, 18 May 2009 08:44:06 +0000 (11:44 +0300)
committerAvi Kivity <avi@redhat.com>
Thu, 10 Sep 2009 05:32:41 +0000 (08:32 +0300)
The problem exists only on VMX. Also currently we skip this step if
there is pending exception. The patch fixes this too.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
arch/x86/kvm/vmx.c
arch/x86/kvm/x86.c

index c87c93fd129ae66275143a62b071cbef122a35ce..c14bffc8c1f9e7591213db52c4965a0594616900 100644 (file)
@@ -3453,6 +3453,14 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
        if (test_bit(VCPU_REGS_RIP, (unsigned long *)&vcpu->arch.regs_dirty))
                vmcs_writel(GUEST_RIP, vcpu->arch.regs[VCPU_REGS_RIP]);
 
+       /* When single-stepping over STI and MOV SS, we must clear the
+        * corresponding interruptibility bits in the guest state. Otherwise
+        * vmentry fails as it then expects bit 14 (BS) in pending debug
+        * exceptions being set, but that's not correct for the guest debugging
+        * case. */
+       if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
+               vmx_set_interrupt_shadow(vcpu, 0);
+
        /*
         * Loading guest fpu may have cleared host cr0.ts
         */
index 25a1c5739dfc9ee98c51f962dde14887848b3de4..f0642396783f809f046c1ea889aefea39b0dbcc8 100644 (file)
@@ -3361,9 +3361,6 @@ static void update_cr8_intercept(struct kvm_vcpu *vcpu)
 
 static void inject_pending_irq(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 {
-       if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
-               kvm_x86_ops->set_interrupt_shadow(vcpu, 0);
-
        /* try to reinject previous events if any */
        if (vcpu->arch.nmi_injected) {
                kvm_x86_ops->set_nmi(vcpu);