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KVM: Do not re-execute INTn instruction.
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Re-inject event instead. This is what Intel suggest. Also use correct
instruction length when re-injecting soft fault/interrupt.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Gleb Natapov authored and Avi Kivity committed Jun 10, 2009
1 parent f629cf8 commit 66fd3f7
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Showing 5 changed files with 47 additions and 18 deletions.
5 changes: 4 additions & 1 deletion arch/x86/include/asm/kvm_host.h
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Original file line number Diff line number Diff line change
Expand Up @@ -319,6 +319,8 @@ struct kvm_vcpu_arch {
struct kvm_pio_request pio;
void *pio_data;

u8 event_exit_inst_len;

struct kvm_queued_exception {
bool pending;
bool has_error_code;
Expand All @@ -328,6 +330,7 @@ struct kvm_vcpu_arch {

struct kvm_queued_interrupt {
bool pending;
bool soft;
u8 nr;
} interrupt;

Expand Down Expand Up @@ -510,7 +513,7 @@ struct kvm_x86_ops {
u32 (*get_interrupt_shadow)(struct kvm_vcpu *vcpu, int mask);
void (*patch_hypercall)(struct kvm_vcpu *vcpu,
unsigned char *hypercall_addr);
void (*set_irq)(struct kvm_vcpu *vcpu, int vec);
void (*set_irq)(struct kvm_vcpu *vcpu);
void (*set_nmi)(struct kvm_vcpu *vcpu);
void (*queue_exception)(struct kvm_vcpu *vcpu, unsigned nr,
bool has_error_code, u32 error_code);
Expand Down
8 changes: 4 additions & 4 deletions arch/x86/kvm/svm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2310,13 +2310,13 @@ static void svm_queue_irq(struct kvm_vcpu *vcpu, unsigned nr)
SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_INTR;
}

static void svm_set_irq(struct kvm_vcpu *vcpu, int irq)
static void svm_set_irq(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);

nested_svm_intr(svm);

svm_queue_irq(vcpu, irq);
svm_queue_irq(vcpu, vcpu->arch.interrupt.nr);
}

static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr)
Expand Down Expand Up @@ -2418,7 +2418,7 @@ static void svm_complete_interrupts(struct vcpu_svm *svm)
case SVM_EXITINTINFO_TYPE_EXEPT:
/* In case of software exception do not reinject an exception
vector, but re-execute and instruction instead */
if (vector == BP_VECTOR || vector == OF_VECTOR)
if (kvm_exception_is_soft(vector))
break;
if (exitintinfo & SVM_EXITINTINFO_VALID_ERR) {
u32 err = svm->vmcb->control.exit_int_info_err;
Expand All @@ -2428,7 +2428,7 @@ static void svm_complete_interrupts(struct vcpu_svm *svm)
kvm_queue_exception(&svm->vcpu, vector);
break;
case SVM_EXITINTINFO_TYPE_INTR:
kvm_queue_interrupt(&svm->vcpu, vector);
kvm_queue_interrupt(&svm->vcpu, vector, false);
break;
default:
break;
Expand Down
32 changes: 25 additions & 7 deletions arch/x86/kvm/vmx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -801,8 +801,9 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
return;
}

if (nr == BP_VECTOR || nr == OF_VECTOR) {
vmcs_write32(VM_ENTRY_INSTRUCTION_LEN, 1);
if (kvm_exception_is_soft(nr)) {
vmcs_write32(VM_ENTRY_INSTRUCTION_LEN,
vmx->vcpu.arch.event_exit_inst_len);
intr_info |= INTR_TYPE_SOFT_EXCEPTION;
} else
intr_info |= INTR_TYPE_HARD_EXCEPTION;
Expand Down Expand Up @@ -2445,9 +2446,11 @@ static void enable_nmi_window(struct kvm_vcpu *vcpu)
vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
}

static void vmx_inject_irq(struct kvm_vcpu *vcpu, int irq)
static void vmx_inject_irq(struct kvm_vcpu *vcpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
uint32_t intr;
int irq = vcpu->arch.interrupt.nr;

KVMTRACE_1D(INJ_VIRQ, vcpu, (u32)irq, handler);

Expand All @@ -2462,8 +2465,14 @@ static void vmx_inject_irq(struct kvm_vcpu *vcpu, int irq)
kvm_rip_write(vcpu, vmx->rmode.irq.rip - 1);
return;
}
vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
irq | INTR_TYPE_EXT_INTR | INTR_INFO_VALID_MASK);
intr = irq | INTR_INFO_VALID_MASK;
if (vcpu->arch.interrupt.soft) {
intr |= INTR_TYPE_SOFT_INTR;
vmcs_write32(VM_ENTRY_INSTRUCTION_LEN,
vmx->vcpu.arch.event_exit_inst_len);
} else
intr |= INTR_TYPE_EXT_INTR;
vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, intr);
}

static void vmx_inject_nmi(struct kvm_vcpu *vcpu)
Expand Down Expand Up @@ -3024,6 +3033,7 @@ static int handle_task_switch(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
GUEST_INTR_STATE_NMI);
break;
case INTR_TYPE_EXT_INTR:
case INTR_TYPE_SOFT_INTR:
kvm_clear_interrupt_queue(vcpu);
break;
case INTR_TYPE_HARD_EXCEPTION:
Expand Down Expand Up @@ -3295,16 +3305,24 @@ static void vmx_complete_interrupts(struct vcpu_vmx *vmx)
vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO,
GUEST_INTR_STATE_NMI);
break;
case INTR_TYPE_HARD_EXCEPTION:
case INTR_TYPE_SOFT_EXCEPTION:
vmx->vcpu.arch.event_exit_inst_len =
vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
/* fall through */
case INTR_TYPE_HARD_EXCEPTION:
if (idt_vectoring_info & VECTORING_INFO_DELIVER_CODE_MASK) {
u32 err = vmcs_read32(IDT_VECTORING_ERROR_CODE);
kvm_queue_exception_e(&vmx->vcpu, vector, err);
} else
kvm_queue_exception(&vmx->vcpu, vector);
break;
case INTR_TYPE_SOFT_INTR:
vmx->vcpu.arch.event_exit_inst_len =
vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
/* fall through */
case INTR_TYPE_EXT_INTR:
kvm_queue_interrupt(&vmx->vcpu, vector);
kvm_queue_interrupt(&vmx->vcpu, vector,
type == INTR_TYPE_SOFT_INTR);
break;
default:
break;
Expand Down
11 changes: 6 additions & 5 deletions arch/x86/kvm/x86.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1441,7 +1441,7 @@ static int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu,
return -ENXIO;
vcpu_load(vcpu);

kvm_queue_interrupt(vcpu, irq->irq);
kvm_queue_interrupt(vcpu, irq->irq, false);

vcpu_put(vcpu);

Expand Down Expand Up @@ -3161,7 +3161,7 @@ static void inject_irq(struct kvm_vcpu *vcpu)
}

if (vcpu->arch.interrupt.pending) {
kvm_x86_ops->set_irq(vcpu, vcpu->arch.interrupt.nr);
kvm_x86_ops->set_irq(vcpu);
return;
}

Expand All @@ -3174,8 +3174,9 @@ static void inject_irq(struct kvm_vcpu *vcpu)
}
} else if (kvm_cpu_has_interrupt(vcpu)) {
if (kvm_x86_ops->interrupt_allowed(vcpu)) {
kvm_queue_interrupt(vcpu, kvm_cpu_get_interrupt(vcpu));
kvm_x86_ops->set_irq(vcpu, vcpu->arch.interrupt.nr);
kvm_queue_interrupt(vcpu, kvm_cpu_get_interrupt(vcpu),
false);
kvm_x86_ops->set_irq(vcpu);
}
}
}
Expand Down Expand Up @@ -4098,7 +4099,7 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
pending_vec = find_first_bit(
(const unsigned long *)sregs->interrupt_bitmap, max_bits);
if (pending_vec < max_bits) {
kvm_queue_interrupt(vcpu, pending_vec);
kvm_queue_interrupt(vcpu, pending_vec, false);
pr_debug("Set back pending irq %d\n", pending_vec);
if (irqchip_in_kernel(vcpu->kvm))
kvm_pic_clear_isr_ack(vcpu->kvm);
Expand Down
9 changes: 8 additions & 1 deletion arch/x86/kvm/x86.h
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Original file line number Diff line number Diff line change
Expand Up @@ -8,9 +8,11 @@ static inline void kvm_clear_exception_queue(struct kvm_vcpu *vcpu)
vcpu->arch.exception.pending = false;
}

static inline void kvm_queue_interrupt(struct kvm_vcpu *vcpu, u8 vector)
static inline void kvm_queue_interrupt(struct kvm_vcpu *vcpu, u8 vector,
bool soft)
{
vcpu->arch.interrupt.pending = true;
vcpu->arch.interrupt.soft = soft;
vcpu->arch.interrupt.nr = vector;
}

Expand All @@ -24,4 +26,9 @@ static inline bool kvm_event_needs_reinjection(struct kvm_vcpu *vcpu)
return vcpu->arch.exception.pending || vcpu->arch.interrupt.pending ||
vcpu->arch.nmi_injected;
}

static inline bool kvm_exception_is_soft(unsigned int nr)
{
return (nr == BP_VECTOR) || (nr == OF_VECTOR);
}
#endif

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