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KVM: x86: Add KVM_GET/SET_VCPU_EVENTS
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This new IOCTL exports all yet user-invisible states related to
exceptions, interrupts, and NMIs. Together with appropriate user space
changes, this fixes sporadic problems of vmsave/restore, live migration
and system reset.

[avi: future-proof abi by adding a flags field]

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Jan Kiszka authored and Avi Kivity committed Dec 3, 2009
1 parent 65ac726 commit 3cfc309
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49 changes: 49 additions & 0 deletions Documentation/kvm/api.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -653,6 +653,55 @@ struct kvm_clock_data {
__u32 pad[9];
};

4.29 KVM_GET_VCPU_EVENTS

Capability: KVM_CAP_VCPU_EVENTS
Architectures: x86
Type: vm ioctl
Parameters: struct kvm_vcpu_event (out)
Returns: 0 on success, -1 on error

Gets currently pending exceptions, interrupts, and NMIs as well as related
states of the vcpu.

struct kvm_vcpu_events {
struct {
__u8 injected;
__u8 nr;
__u8 has_error_code;
__u8 pad;
__u32 error_code;
} exception;
struct {
__u8 injected;
__u8 nr;
__u8 soft;
__u8 pad;
} interrupt;
struct {
__u8 injected;
__u8 pending;
__u8 masked;
__u8 pad;
} nmi;
__u32 sipi_vector;
__u32 flags; /* must be zero */
};

4.30 KVM_SET_VCPU_EVENTS

Capability: KVM_CAP_VCPU_EVENTS
Architectures: x86
Type: vm ioctl
Parameters: struct kvm_vcpu_event (in)
Returns: 0 on success, -1 on error

Set pending exceptions, interrupts, and NMIs as well as related states of the
vcpu.

See KVM_GET_VCPU_EVENTS for the data structure.


5. The kvm_run structure

Application code obtains a pointer to the kvm_run structure by
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28 changes: 28 additions & 0 deletions arch/x86/include/asm/kvm.h
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Expand Up @@ -20,6 +20,7 @@
#define __KVM_HAVE_MCE
#define __KVM_HAVE_PIT_STATE2
#define __KVM_HAVE_XEN_HVM
#define __KVM_HAVE_VCPU_EVENTS

/* Architectural interrupt line count. */
#define KVM_NR_INTERRUPTS 256
Expand Down Expand Up @@ -252,4 +253,31 @@ struct kvm_reinject_control {
__u8 pit_reinject;
__u8 reserved[31];
};

/* for KVM_GET/SET_VCPU_EVENTS */
struct kvm_vcpu_events {
struct {
__u8 injected;
__u8 nr;
__u8 has_error_code;
__u8 pad;
__u32 error_code;
} exception;
struct {
__u8 injected;
__u8 nr;
__u8 soft;
__u8 pad;
} interrupt;
struct {
__u8 injected;
__u8 pending;
__u8 masked;
__u8 pad;
} nmi;
__u32 sipi_vector;
__u32 flags;
__u32 reserved[10];
};

#endif /* _ASM_X86_KVM_H */
2 changes: 2 additions & 0 deletions arch/x86/include/asm/kvm_host.h
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Expand Up @@ -523,6 +523,8 @@ struct kvm_x86_ops {
bool has_error_code, u32 error_code);
int (*interrupt_allowed)(struct kvm_vcpu *vcpu);
int (*nmi_allowed)(struct kvm_vcpu *vcpu);
bool (*get_nmi_mask)(struct kvm_vcpu *vcpu);
void (*set_nmi_mask)(struct kvm_vcpu *vcpu, bool masked);
void (*enable_nmi_window)(struct kvm_vcpu *vcpu);
void (*enable_irq_window)(struct kvm_vcpu *vcpu);
void (*update_cr8_intercept)(struct kvm_vcpu *vcpu, int tpr, int irr);
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22 changes: 22 additions & 0 deletions arch/x86/kvm/svm.c
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Expand Up @@ -2499,6 +2499,26 @@ static int svm_nmi_allowed(struct kvm_vcpu *vcpu)
!(svm->vcpu.arch.hflags & HF_NMI_MASK);
}

static bool svm_get_nmi_mask(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);

return !!(svm->vcpu.arch.hflags & HF_NMI_MASK);
}

static void svm_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked)
{
struct vcpu_svm *svm = to_svm(vcpu);

if (masked) {
svm->vcpu.arch.hflags |= HF_NMI_MASK;
svm->vmcb->control.intercept |= (1UL << INTERCEPT_IRET);
} else {
svm->vcpu.arch.hflags &= ~HF_NMI_MASK;
svm->vmcb->control.intercept &= ~(1UL << INTERCEPT_IRET);
}
}

static int svm_interrupt_allowed(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
Expand Down Expand Up @@ -2946,6 +2966,8 @@ static struct kvm_x86_ops svm_x86_ops = {
.queue_exception = svm_queue_exception,
.interrupt_allowed = svm_interrupt_allowed,
.nmi_allowed = svm_nmi_allowed,
.get_nmi_mask = svm_get_nmi_mask,
.set_nmi_mask = svm_set_nmi_mask,
.enable_nmi_window = enable_nmi_window,
.enable_irq_window = enable_irq_window,
.update_cr8_intercept = update_cr8_intercept,
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30 changes: 30 additions & 0 deletions arch/x86/kvm/vmx.c
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Expand Up @@ -2639,6 +2639,34 @@ static int vmx_nmi_allowed(struct kvm_vcpu *vcpu)
GUEST_INTR_STATE_NMI));
}

static bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu)
{
if (!cpu_has_virtual_nmis())
return to_vmx(vcpu)->soft_vnmi_blocked;
else
return !!(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) &
GUEST_INTR_STATE_NMI);
}

static void vmx_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);

if (!cpu_has_virtual_nmis()) {
if (vmx->soft_vnmi_blocked != masked) {
vmx->soft_vnmi_blocked = masked;
vmx->vnmi_blocked_time = 0;
}
} else {
if (masked)
vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO,
GUEST_INTR_STATE_NMI);
else
vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO,
GUEST_INTR_STATE_NMI);
}
}

static int vmx_interrupt_allowed(struct kvm_vcpu *vcpu)
{
return (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) &&
Expand Down Expand Up @@ -3985,6 +4013,8 @@ static struct kvm_x86_ops vmx_x86_ops = {
.queue_exception = vmx_queue_exception,
.interrupt_allowed = vmx_interrupt_allowed,
.nmi_allowed = vmx_nmi_allowed,
.get_nmi_mask = vmx_get_nmi_mask,
.set_nmi_mask = vmx_set_nmi_mask,
.enable_nmi_window = enable_nmi_window,
.enable_irq_window = enable_irq_window,
.update_cr8_intercept = update_cr8_intercept,
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77 changes: 77 additions & 0 deletions arch/x86/kvm/x86.c
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Expand Up @@ -1342,6 +1342,7 @@ int kvm_dev_ioctl_check_extension(long ext)
case KVM_CAP_SET_IDENTITY_MAP_ADDR:
case KVM_CAP_XEN_HVM:
case KVM_CAP_ADJUST_CLOCK:
case KVM_CAP_VCPU_EVENTS:
r = 1;
break;
case KVM_CAP_COALESCED_MMIO:
Expand Down Expand Up @@ -1883,6 +1884,61 @@ static int kvm_vcpu_ioctl_x86_set_mce(struct kvm_vcpu *vcpu,
return 0;
}

static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu,
struct kvm_vcpu_events *events)
{
vcpu_load(vcpu);

events->exception.injected = vcpu->arch.exception.pending;
events->exception.nr = vcpu->arch.exception.nr;
events->exception.has_error_code = vcpu->arch.exception.has_error_code;
events->exception.error_code = vcpu->arch.exception.error_code;

events->interrupt.injected = vcpu->arch.interrupt.pending;
events->interrupt.nr = vcpu->arch.interrupt.nr;
events->interrupt.soft = vcpu->arch.interrupt.soft;

events->nmi.injected = vcpu->arch.nmi_injected;
events->nmi.pending = vcpu->arch.nmi_pending;
events->nmi.masked = kvm_x86_ops->get_nmi_mask(vcpu);

events->sipi_vector = vcpu->arch.sipi_vector;

events->flags = 0;

vcpu_put(vcpu);
}

static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
struct kvm_vcpu_events *events)
{
if (events->flags)
return -EINVAL;

vcpu_load(vcpu);

vcpu->arch.exception.pending = events->exception.injected;
vcpu->arch.exception.nr = events->exception.nr;
vcpu->arch.exception.has_error_code = events->exception.has_error_code;
vcpu->arch.exception.error_code = events->exception.error_code;

vcpu->arch.interrupt.pending = events->interrupt.injected;
vcpu->arch.interrupt.nr = events->interrupt.nr;
vcpu->arch.interrupt.soft = events->interrupt.soft;
if (vcpu->arch.interrupt.pending && irqchip_in_kernel(vcpu->kvm))
kvm_pic_clear_isr_ack(vcpu->kvm);

vcpu->arch.nmi_injected = events->nmi.injected;
vcpu->arch.nmi_pending = events->nmi.pending;
kvm_x86_ops->set_nmi_mask(vcpu, events->nmi.masked);

vcpu->arch.sipi_vector = events->sipi_vector;

vcpu_put(vcpu);

return 0;
}

long kvm_arch_vcpu_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
Expand Down Expand Up @@ -2040,6 +2096,27 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
r = kvm_vcpu_ioctl_x86_set_mce(vcpu, &mce);
break;
}
case KVM_GET_VCPU_EVENTS: {
struct kvm_vcpu_events events;

kvm_vcpu_ioctl_x86_get_vcpu_events(vcpu, &events);

r = -EFAULT;
if (copy_to_user(argp, &events, sizeof(struct kvm_vcpu_events)))
break;
r = 0;
break;
}
case KVM_SET_VCPU_EVENTS: {
struct kvm_vcpu_events events;

r = -EFAULT;
if (copy_from_user(&events, argp, sizeof(struct kvm_vcpu_events)))
break;

r = kvm_vcpu_ioctl_x86_set_vcpu_events(vcpu, &events);
break;
}
default:
r = -EINVAL;
}
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6 changes: 6 additions & 0 deletions include/linux/kvm.h
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Original file line number Diff line number Diff line change
Expand Up @@ -489,6 +489,9 @@ struct kvm_ioeventfd {
#endif
#define KVM_CAP_ADJUST_CLOCK 39
#define KVM_CAP_INTERNAL_ERROR_DATA 40
#ifdef __KVM_HAVE_VCPU_EVENTS
#define KVM_CAP_VCPU_EVENTS 41
#endif

#ifdef KVM_CAP_IRQ_ROUTING

Expand Down Expand Up @@ -672,6 +675,9 @@ struct kvm_clock_data {
/* IA64 stack access */
#define KVM_IA64_VCPU_GET_STACK _IOR(KVMIO, 0x9a, void *)
#define KVM_IA64_VCPU_SET_STACK _IOW(KVMIO, 0x9b, void *)
/* Available with KVM_CAP_VCPU_EVENTS */
#define KVM_GET_VCPU_EVENTS _IOR(KVMIO, 0x9f, struct kvm_vcpu_events)
#define KVM_SET_VCPU_EVENTS _IOW(KVMIO, 0xa0, struct kvm_vcpu_events)

#define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0)

Expand Down

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