[PATCH 06/45] KVM: VMX: refactor/fix IRQ and NMI injectability determination

Avi Kivity
2008-12-08T11:52:59Z

From: Jan Kiszka <jan.kiszka@siemens.com>

There are currently two ways in VMX to check if an IRQ or NMI can be
injected:
- vmx_{nmi|irq}_enabled and
- vcpu.arch.{nmi|interrupt}_window_open.
Even worse, one test (at the end of vmx_vcpu_run) uses an inconsistent,
likely incorrect logic.

This patch consolidates and unifies the tests over
{nmi|interrupt}_window_open as cache + vmx_update_window_states
for updating the cache content.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/vmx.c | 46 +++++++++++++++++---------------------
2 files changed, 22 insertions(+), 25 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 8346be8..bfbbdea 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -327,6 +327,7 @@ struct kvm_vcpu_arch {

bool nmi_pending;
bool nmi_injected;
+ bool nmi_window_open;

u64 mtrr[0x100];
};
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 8d0fc68..f0866e1 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2362,6 +2362,21 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu)
INTR_TYPE_NMI_INTR | INTR_INFO_VALID_MASK | NMI_VECTOR);
}

+static void vmx_update_window_states(struct kvm_vcpu *vcpu)
+{
+ u32 guest_intr = vmcs_read32(GUEST_INTERRUPTIBILITY_INFO);
+
+ vcpu->arch.nmi_window_open =
+ !(guest_intr & (GUEST_INTR_STATE_STI |
+ GUEST_INTR_STATE_MOV_SS |
+ GUEST_INTR_STATE_NMI));
+
+ vcpu->arch.interrupt_window_open =
+ ((vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) &&
+ !(guest_intr & (GUEST_INTR_STATE_STI |
+ GUEST_INTR_STATE_MOV_SS)));
+}
+
static void kvm_do_inject_irq(struct kvm_vcpu *vcpu)
{
int word_index = __ffs(vcpu->arch.irq_summary);
@@ -2374,15 +2389,12 @@ static void kvm_do_inject_irq(struct kvm_vcpu *vcpu)
kvm_queue_interrupt(vcpu, irq);
}

-
static void do_interrupt_requests(struct kvm_vcpu *vcpu,
struct kvm_run *kvm_run)
{
u32 cpu_based_vm_exec_control;

- vcpu->arch.interrupt_window_open =
- ((vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) &&
- (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & 3) == 0);
+ vmx_update_window_states(vcpu);

if (vcpu->arch.interrupt_window_open &&
vcpu->arch.irq_summary && !vcpu->arch.interrupt.pending)
@@ -3075,22 +3087,6 @@ static void enable_nmi_window(struct kvm_vcpu *vcpu)
vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
}

-static int vmx_nmi_enabled(struct kvm_vcpu *vcpu)
-{
- u32 guest_intr = vmcs_read32(GUEST_INTERRUPTIBILITY_INFO);
- return !(guest_intr & (GUEST_INTR_STATE_NMI |
- GUEST_INTR_STATE_MOV_SS |
- GUEST_INTR_STATE_STI));
-}
-
-static int vmx_irq_enabled(struct kvm_vcpu *vcpu)
-{
- u32 guest_intr = vmcs_read32(GUEST_INTERRUPTIBILITY_INFO);
- return (!(guest_intr & (GUEST_INTR_STATE_MOV_SS |
- GUEST_INTR_STATE_STI)) &&
- (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF));
-}
-
static void enable_intr_window(struct kvm_vcpu *vcpu)
{
if (vcpu->arch.nmi_pending)
@@ -3159,11 +3155,13 @@ static void vmx_intr_assist(struct kvm_vcpu *vcpu)
{
update_tpr_threshold(vcpu);

+ vmx_update_window_states(vcpu);
+
if (cpu_has_virtual_nmis()) {
if (vcpu->arch.nmi_pending && !vcpu->arch.nmi_injected) {
if (vcpu->arch.interrupt.pending) {
enable_nmi_window(vcpu);
- } else if (vmx_nmi_enabled(vcpu)) {
+ } else if (vcpu->arch.nmi_window_open) {
vcpu->arch.nmi_pending = false;
vcpu->arch.nmi_injected = true;
} else {
@@ -3178,7 +3176,7 @@ static void vmx_intr_assist(struct kvm_vcpu *vcpu)
}
}
if (!vcpu->arch.interrupt.pending && kvm_cpu_has_interrupt(vcpu)) {
- if (vmx_irq_enabled(vcpu))
+ if (vcpu->arch.interrupt_window_open)
kvm_queue_interrupt(vcpu, kvm_cpu_get_interrupt(vcpu));
else
enable_irq_window(vcpu);
@@ -3339,9 +3337,7 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
if (vmx->rmode.irq.pending)
fixup_rmode_irq(vmx);

- vcpu->arch.interrupt_window_open =
- (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) &
- (GUEST_INTR_STATE_STI | GUEST_INTR_STATE_MOV_SS)) == 0;
+ vmx_update_window_states(vcpu);

asm("mov %0, %%ds; mov %0, %%es" : : "r"(__USER_DS));
vmx->launched = 1;
--
1.6.0.3