KVM: Non-atomic interrupt injection
Change the interrupt injection code to work from preemptible, interrupts
enabled context. This works by adding a ->cancel_injection() operation
that undoes an injection in case we were not able to actually enter the guest
(this condition could never happen with atomic injection).
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index b43686a..80224bf 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -552,6 +552,7 @@
void (*queue_exception)(struct kvm_vcpu *vcpu, unsigned nr,
bool has_error_code, u32 error_code,
bool reinject);
+ void (*cancel_injection)(struct kvm_vcpu *vcpu);
int (*interrupt_allowed)(struct kvm_vcpu *vcpu);
int (*nmi_allowed)(struct kvm_vcpu *vcpu);
bool (*get_nmi_mask)(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 1d2ea65..1a85fc5 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3261,6 +3261,17 @@
}
}
+static void svm_cancel_injection(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_svm *svm = to_svm(vcpu);
+ struct vmcb_control_area *control = &svm->vmcb->control;
+
+ control->exit_int_info = control->event_inj;
+ control->exit_int_info_err = control->event_inj_err;
+ control->event_inj = 0;
+ svm_complete_interrupts(svm);
+}
+
#ifdef CONFIG_X86_64
#define R "r"
#else
@@ -3631,6 +3642,7 @@
.set_irq = svm_set_irq,
.set_nmi = svm_inject_nmi,
.queue_exception = svm_queue_exception,
+ .cancel_injection = svm_cancel_injection,
.interrupt_allowed = svm_interrupt_allowed,
.nmi_allowed = svm_nmi_allowed,
.get_nmi_mask = svm_get_nmi_mask,
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 3237f6c..70af3db 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3895,6 +3895,16 @@
IDT_VECTORING_ERROR_CODE);
}
+static void vmx_cancel_injection(struct kvm_vcpu *vcpu)
+{
+ __vmx_complete_interrupts(to_vmx(vcpu),
+ vmcs_read32(VM_ENTRY_INTR_INFO_FIELD),
+ VM_ENTRY_INSTRUCTION_LEN,
+ VM_ENTRY_EXCEPTION_ERROR_CODE);
+
+ vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, 0);
+}
+
/*
* Failure to inject an interrupt should give us the information
* in IDT_VECTORING_INFO_FIELD. However, if the failure occurs
@@ -4348,6 +4358,7 @@
.set_irq = vmx_inject_irq,
.set_nmi = vmx_inject_nmi,
.queue_exception = vmx_queue_exception,
+ .cancel_injection = vmx_cancel_injection,
.interrupt_allowed = vmx_interrupt_allowed,
.nmi_allowed = vmx_nmi_allowed,
.get_nmi_mask = vmx_get_nmi_mask,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e719803..a465bd2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5005,7 +5005,6 @@
int r;
bool req_int_win = !irqchip_in_kernel(vcpu->kvm) &&
vcpu->run->request_interrupt_window;
- bool req_event;
if (vcpu->requests) {
if (kvm_check_request(KVM_REQ_MMU_RELOAD, vcpu))
@@ -5041,33 +5040,7 @@
if (unlikely(r))
goto out;
- preempt_disable();
-
- kvm_x86_ops->prepare_guest_switch(vcpu);
- if (vcpu->fpu_active)
- kvm_load_guest_fpu(vcpu);
- kvm_load_guest_xcr0(vcpu);
-
- atomic_set(&vcpu->guest_mode, 1);
- smp_wmb();
-
- local_irq_disable();
-
- req_event = kvm_check_request(KVM_REQ_EVENT, vcpu);
-
- if (!atomic_read(&vcpu->guest_mode) || vcpu->requests
- || need_resched() || signal_pending(current)) {
- if (req_event)
- kvm_make_request(KVM_REQ_EVENT, vcpu);
- atomic_set(&vcpu->guest_mode, 0);
- smp_wmb();
- local_irq_enable();
- preempt_enable();
- r = 1;
- goto out;
- }
-
- if (req_event || req_int_win) {
+ if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) {
inject_pending_event(vcpu);
/* enable NMI/IRQ window open exits if needed */
@@ -5082,6 +5055,29 @@
}
}
+ preempt_disable();
+
+ kvm_x86_ops->prepare_guest_switch(vcpu);
+ if (vcpu->fpu_active)
+ kvm_load_guest_fpu(vcpu);
+ kvm_load_guest_xcr0(vcpu);
+
+ atomic_set(&vcpu->guest_mode, 1);
+ smp_wmb();
+
+ local_irq_disable();
+
+ if (!atomic_read(&vcpu->guest_mode) || vcpu->requests
+ || need_resched() || signal_pending(current)) {
+ atomic_set(&vcpu->guest_mode, 0);
+ smp_wmb();
+ local_irq_enable();
+ preempt_enable();
+ kvm_x86_ops->cancel_injection(vcpu);
+ r = 1;
+ goto out;
+ }
+
srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
kvm_guest_enter();
