KVM: VMX: Allow single-stepping when uninterruptible (55934c0b) · Commits · 戴 / test

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. Note that clearing those bits is safe as we check for interruptibility based on the original state and do not inject interrupts or NMIs if guest interruptibility was blocked. Signed-off-by:

Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by:

Avi Kivity <avi@redhat.com>

arch/x86/kvm/vmx.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -2478,6 +2478,11 @@ static void do_interrupt_requests(struct kvm_vcpu *vcpu,
		{
		vmx_update_window_states(vcpu);

		if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
		vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO,
		GUEST_INTR_STATE_STI \|
		GUEST_INTR_STATE_MOV_SS);

		if (vcpu->arch.nmi_pending && !vcpu->arch.nmi_injected) {
		if (vcpu->arch.interrupt.pending) {
		enable_nmi_window(vcpu);
		@@ -3244,6 +3249,11 @@ static void vmx_intr_assist(struct kvm_vcpu *vcpu)

		vmx_update_window_states(vcpu);

		if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
		vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO,
		GUEST_INTR_STATE_STI \|
		GUEST_INTR_STATE_MOV_SS);

		if (vcpu->arch.nmi_pending && !vcpu->arch.nmi_injected) {
		if (vcpu->arch.interrupt.pending) {
		enable_nmi_window(vcpu);

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