Re: [PATCH 9/11] VMX: Provide support for user space injected NMIs

[Jan Kiszka <jan.kiszka@siemens.com>]

Yang, Sheng wrote:
> On Monday 22 September 2008 15:59:02 Jan Kiszka wrote:
>> This patch adds the required bits to the VMX side for user space
>> injected NMIs. As with the preexisting in-kernel irqchip support, the
>> CPU must provide the "virtual NMI" feature for proper tracking of the
>> NMI blocking state.
>>
>> Based on the original patch by Sheng Yang.
>>
>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>> ---
>>  arch/x86/kvm/vmx.c |   33 +++++++++++++++++++++++++++++++++
>>  1 file changed, 33 insertions(+)
>>
>> Index: b/arch/x86/kvm/vmx.c
>> ===================================================================
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -2356,6 +2356,7 @@ static void vmx_inject_nmi(struct kvm_vc
>>  {
>>         struct vcpu_vmx *vmx = to_vmx(vcpu);
>>
>> +       ++vcpu->stat.nmi_injections;
>>         if (vcpu->arch.rmode.active) {
>>                 vmx->rmode.irq.pending = true;
>>                 vmx->rmode.irq.vector = NMI_VECTOR;
>> @@ -2424,6 +2425,30 @@ static void do_interrupt_requests(struct
>>  {
>>         vmx_update_window_states(vcpu);
>>
>> +       if (cpu_has_virtual_nmis()) {
>> +               if (vcpu->arch.nmi_pending && !vcpu->arch.nmi_injected) {
>> +                       if (vcpu->arch.nmi_window_open) {
>> +                               vcpu->arch.nmi_pending = false;
>> +                               vcpu->arch.nmi_injected = true;
>> +                       } else {
>> +                               enable_nmi_window(vcpu);
>> +                               return;
>> +                       }
>> +               }
>> +               if (vcpu->arch.nmi_injected) {
>> +                       vmx_inject_nmi(vcpu);
>> +                       if (vcpu->arch.nmi_pending
>> +                           || kvm_run->request_nmi_window)
>> +                               enable_nmi_window(vcpu);
>> +                       else if (vcpu->arch.irq_summary
>> +                                || kvm_run->request_interrupt_window)
>> +                               enable_irq_window(vcpu);
>> +                       return;
>> +               }
>> +               if (!vcpu->arch.nmi_window_open ||
>> kvm_run->request_nmi_window) +                      
>> enable_nmi_window(vcpu);
>> +       }
>> +
>>         if (vcpu->arch.interrupt_window_open) {
>>                 if (vcpu->arch.irq_summary &&
>> !vcpu->arch.interrupt.pending) kvm_do_inject_irq(vcpu);
>> @@ -2936,6 +2961,14 @@ static int handle_nmi_window(struct kvm_
>>         vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
>>         ++vcpu->stat.nmi_window_exits;
>>
>> +       /*
>> +        * If the user space waits to inject a NNI, exit as soon as
>> possible +        */
> 
> o... found a typo :)

Fatal! Fixed-up version below.

---------

This patch adds the required bits to the VMX side for user space
injected NMIs. As with the preexisting in-kernel irqchip support, the
CPU must provide the "virtual NMI" feature for proper tracking of the
NMI blocking state.

Based on the original patch by Sheng Yang.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 arch/x86/kvm/vmx.c |   33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

Index: b/arch/x86/kvm/vmx.c
===================================================================
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2356,6 +2356,7 @@ static void vmx_inject_nmi(struct kvm_vc
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 
+	++vcpu->stat.nmi_injections;
 	if (vcpu->arch.rmode.active) {
 		vmx->rmode.irq.pending = true;
 		vmx->rmode.irq.vector = NMI_VECTOR;
@@ -2424,6 +2425,30 @@ static void do_interrupt_requests(struct
 {
 	vmx_update_window_states(vcpu);
 
+	if (cpu_has_virtual_nmis()) {
+		if (vcpu->arch.nmi_pending && !vcpu->arch.nmi_injected) {
+			if (vcpu->arch.nmi_window_open) {
+				vcpu->arch.nmi_pending = false;
+				vcpu->arch.nmi_injected = true;
+			} else {
+				enable_nmi_window(vcpu);
+				return;
+			}
+		}
+		if (vcpu->arch.nmi_injected) {
+			vmx_inject_nmi(vcpu);
+			if (vcpu->arch.nmi_pending
+			    || kvm_run->request_nmi_window)
+				enable_nmi_window(vcpu);
+			else if (vcpu->arch.irq_summary
+				 || kvm_run->request_interrupt_window)
+				enable_irq_window(vcpu);
+			return;
+		}
+		if (!vcpu->arch.nmi_window_open || kvm_run->request_nmi_window)
+			enable_nmi_window(vcpu);
+	}
+
 	if (vcpu->arch.interrupt_window_open) {
 		if (vcpu->arch.irq_summary && !vcpu->arch.interrupt.pending)
 			kvm_do_inject_irq(vcpu);
@@ -2936,6 +2961,14 @@ static int handle_nmi_window(struct kvm_
 	vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
 	++vcpu->stat.nmi_window_exits;
 
+	/*
+	 * If the user space waits to inject a NMI, exit as soon as possible
+	 */
+	if (kvm_run->request_nmi_window && !vcpu->arch.nmi_pending) {
+		kvm_run->exit_reason = KVM_EXIT_NMI_WINDOW_OPEN;
+		return 0;
+	}
+
 	return 1;
 }