KVM: x86: Add KVM_GET/SET_VCPU_EVENTS

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>

diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt
index 36594ba..e1a1141 100644 (file)
--- a/Documentation/kvm/api.txt
+++ b/Documentation/kvm/api.txt
@@ -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

diff --git a/arch/x86/include/asm/kvm.h b/arch/x86/include/asm/kvm.h
index ef9b4b7..950df43 100644 (file)
--- a/arch/x86/include/asm/kvm.h
+++ b/arch/x86/include/asm/kvm.h
@@ -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
@@ -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 */

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 26a74b7..06e0856 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -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);

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 34b700f..3de0b37 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -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);
@@ -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,

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 22fcd27..778f059 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -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) &&
@@ -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,

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ba8958d..35eea30 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -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:
@@ -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)
 {
@@ -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;
        }

diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 976f4d1..92045a9 100644 (file)
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -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
 
@@ -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)