KVM: x86: API changes for SMM support

This patch includes changes to the external API for SMM support.
Userspace can predicate the availability of the new fields and
ioctls on a new capability, KVM_CAP_X86_SMM, which is added at the end
of the patch series.

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Documentation/virtual/kvm/api.txt

@@ -820,11 +820,21 @@ struct kvm_vcpu_events {
 	} nmi;
 	__u32 sipi_vector;
 	__u32 flags;
+	struct {
+		__u8 smm;
+		__u8 pending;
+		__u8 smm_inside_nmi;
+		__u8 latched_init;
+	} smi;
 };
 
-KVM_VCPUEVENT_VALID_SHADOW may be set in the flags field to signal that
-interrupt.shadow contains a valid state. Otherwise, this field is undefined.
+Only two fields are defined in the flags field:
+
+- KVM_VCPUEVENT_VALID_SHADOW may be set in the flags field to signal that
+  interrupt.shadow contains a valid state.
 
+- KVM_VCPUEVENT_VALID_SMM may be set in the flags field to signal that
+  smi contains a valid state.
 
 4.32 KVM_SET_VCPU_EVENTS
 
@@ -841,17 +851,20 @@ vcpu.
 See KVM_GET_VCPU_EVENTS for the data structure.
 
 Fields that may be modified asynchronously by running VCPUs can be excluded
-from the update. These fields are nmi.pending and sipi_vector. Keep the
-corresponding bits in the flags field cleared to suppress overwriting the
-current in-kernel state. The bits are:
+from the update. These fields are nmi.pending, sipi_vector, smi.smm,
+smi.pending. Keep the corresponding bits in the flags field cleared to
+suppress overwriting the current in-kernel state. The bits are:
 
 KVM_VCPUEVENT_VALID_NMI_PENDING - transfer nmi.pending to the kernel
 KVM_VCPUEVENT_VALID_SIPI_VECTOR - transfer sipi_vector
+KVM_VCPUEVENT_VALID_SMM         - transfer the smi sub-struct.
 
 If KVM_CAP_INTR_SHADOW is available, KVM_VCPUEVENT_VALID_SHADOW can be set in
 the flags field to signal that interrupt.shadow contains a valid state and
 shall be written into the VCPU.
 
+KVM_VCPUEVENT_VALID_SMM can only be set if KVM_CAP_X86_SMM is available.
+
 
 4.33 KVM_GET_DEBUGREGS
 
@@ -2979,6 +2992,16 @@ len must be a multiple of sizeof(struct kvm_s390_irq). It must be > 0
 and it must not exceed (max_vcpus + 32) * sizeof(struct kvm_s390_irq),
 which is the maximum number of possibly pending cpu-local interrupts.
 
+4.90 KVM_SMI
+
+Capability: KVM_CAP_X86_SMM
+Architectures: x86
+Type: vcpu ioctl
+Parameters: none
+Returns: 0 on success, -1 on error
+
+Queues an SMI on the thread's vcpu.
+
 5. The kvm_run structure
 ------------------------
 
@@ -3014,7 +3037,12 @@ an interrupt can be injected now with KVM_INTERRUPT.
 The value of the current interrupt flag.  Only valid if in-kernel
 local APIC is not used.
 
-	__u8 padding2[2];
+	__u16 flags;
+
+More architecture-specific flags detailing state of the VCPU that may
+affect the device's behavior.  The only currently defined flag is
+KVM_RUN_X86_SMM, which is valid on x86 machines and is set if the
+VCPU is in system management mode.
 
 	/* in (pre_kvm_run), out (post_kvm_run) */
 	__u64 cr8;

arch/x86/include/asm/kvm_host.h

@@ -471,6 +471,7 @@ struct kvm_vcpu_arch {
 	atomic_t nmi_queued;  /* unprocessed asynchronous NMIs */
 	unsigned nmi_pending; /* NMI queued after currently running handler */
 	bool nmi_injected;    /* Trying to inject an NMI this entry */
+	bool smi_pending;    /* SMI queued after currently running handler */
 
 	struct mtrr_state_type mtrr_state;
 	u64 pat;
@@ -1115,6 +1116,8 @@ enum {
 #define HF_NMI_MASK		(1 << 3)
 #define HF_IRET_MASK		(1 << 4)
 #define HF_GUEST_MASK		(1 << 5) /* VCPU is in guest-mode */
+#define HF_SMM_MASK		(1 << 6)
+#define HF_SMM_INSIDE_NMI_MASK	(1 << 7)
 
 /*
  * Hardware virtualization extension instructions may fault if a

arch/x86/include/uapi/asm/kvm.h

@@ -106,6 +106,8 @@ struct kvm_ioapic_state {
 #define KVM_IRQCHIP_IOAPIC       2
 #define KVM_NR_IRQCHIPS          3
 
+#define KVM_RUN_X86_SMM		 (1 << 0)
+
 /* for KVM_GET_REGS and KVM_SET_REGS */
 struct kvm_regs {
 	/* out (KVM_GET_REGS) / in (KVM_SET_REGS) */
@@ -281,6 +283,7 @@ struct kvm_reinject_control {
 #define KVM_VCPUEVENT_VALID_NMI_PENDING	0x00000001
 #define KVM_VCPUEVENT_VALID_SIPI_VECTOR	0x00000002
 #define KVM_VCPUEVENT_VALID_SHADOW	0x00000004
+#define KVM_VCPUEVENT_VALID_SMM		0x00000008
 
 /* Interrupt shadow states */
 #define KVM_X86_SHADOW_INT_MOV_SS	0x01
@@ -309,7 +312,13 @@ struct kvm_vcpu_events {
 	} nmi;
 	__u32 sipi_vector;
 	__u32 flags;
-	__u32 reserved[10];
+	struct {
+		__u8 smm;
+		__u8 pending;
+		__u8 smm_inside_nmi;
+		__u8 latched_init;
+	} smi;
+	__u32 reserved[9];
 };
 
 /* for KVM_GET/SET_DEBUGREGS */

arch/x86/kvm/kvm_cache_regs.h

@@ -99,4 +99,9 @@ static inline bool is_guest_mode(struct kvm_vcpu *vcpu)
 	return vcpu->arch.hflags & HF_GUEST_MASK;
 }
 
+static inline bool is_smm(struct kvm_vcpu *vcpu)
+{
+	return vcpu->arch.hflags & HF_SMM_MASK;
+}
+
 #endif

arch/x86/kvm/lapic.h

@@ -159,6 +159,11 @@ static inline bool kvm_lowest_prio_delivery(struct kvm_lapic_irq *irq)
 			irq->msi_redir_hint);
 }
 
+static inline int kvm_lapic_latched_init(struct kvm_vcpu *vcpu)
+{
+	return kvm_vcpu_has_lapic(vcpu) && test_bit(KVM_APIC_INIT, &vcpu->arch.apic->pending_events);
+}
+
 bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector);
 
 void wait_lapic_expire(struct kvm_vcpu *vcpu);

arch/x86/kvm/x86.c

@@ -3101,6 +3101,11 @@ static int kvm_vcpu_ioctl_nmi(struct kvm_vcpu *vcpu)
 	return 0;
 }
 
+static int kvm_vcpu_ioctl_smi(struct kvm_vcpu *vcpu)
+{
+	return 0;
+}
+
 static int vcpu_ioctl_tpr_access_reporting(struct kvm_vcpu *vcpu,
 					   struct kvm_tpr_access_ctl *tac)
 {
@@ -3206,8 +3211,15 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu,
 
 	events->sipi_vector = 0; /* never valid when reporting to user space */
 
+	events->smi.smm = is_smm(vcpu);
+	events->smi.pending = vcpu->arch.smi_pending;
+	events->smi.smm_inside_nmi =
+		!!(vcpu->arch.hflags & HF_SMM_INSIDE_NMI_MASK);
+	events->smi.latched_init = kvm_lapic_latched_init(vcpu);
+
 	events->flags = (KVM_VCPUEVENT_VALID_NMI_PENDING
-			 | KVM_VCPUEVENT_VALID_SHADOW);
+			 | KVM_VCPUEVENT_VALID_SHADOW
+			 | KVM_VCPUEVENT_VALID_SMM);
 	memset(&events->reserved, 0, sizeof(events->reserved));
 }
 
@@ -3216,7 +3228,8 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
 {
 	if (events->flags & ~(KVM_VCPUEVENT_VALID_NMI_PENDING
 			      | KVM_VCPUEVENT_VALID_SIPI_VECTOR
-			      | KVM_VCPUEVENT_VALID_SHADOW))
+			      | KVM_VCPUEVENT_VALID_SHADOW
+			      | KVM_VCPUEVENT_VALID_SMM))
 		return -EINVAL;
 
 	process_nmi(vcpu);
@@ -3241,6 +3254,24 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
 	    kvm_vcpu_has_lapic(vcpu))
 		vcpu->arch.apic->sipi_vector = events->sipi_vector;
 
+	if (events->flags & KVM_VCPUEVENT_VALID_SMM) {
+		if (events->smi.smm)
+			vcpu->arch.hflags |= HF_SMM_MASK;
+		else
+			vcpu->arch.hflags &= ~HF_SMM_MASK;
+		vcpu->arch.smi_pending = events->smi.pending;
+		if (events->smi.smm_inside_nmi)
+			vcpu->arch.hflags |= HF_SMM_INSIDE_NMI_MASK;
+		else
+			vcpu->arch.hflags &= ~HF_SMM_INSIDE_NMI_MASK;
+		if (kvm_vcpu_has_lapic(vcpu)) {
+			if (events->smi.latched_init)
+				set_bit(KVM_APIC_INIT, &vcpu->arch.apic->pending_events);
+			else
+				clear_bit(KVM_APIC_INIT, &vcpu->arch.apic->pending_events);
+		}
+	}
+
 	kvm_make_request(KVM_REQ_EVENT, vcpu);
 
 	return 0;
@@ -3500,6 +3531,10 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 		r = kvm_vcpu_ioctl_nmi(vcpu);
 		break;
 	}
+	case KVM_SMI: {
+		r = kvm_vcpu_ioctl_smi(vcpu);
+		break;
+	}
 	case KVM_SET_CPUID: {
 		struct kvm_cpuid __user *cpuid_arg = argp;
 		struct kvm_cpuid cpuid;
@@ -6182,6 +6217,7 @@ static void post_kvm_run_save(struct kvm_vcpu *vcpu)
 	struct kvm_run *kvm_run = vcpu->run;
 
 	kvm_run->if_flag = (kvm_get_rflags(vcpu) & X86_EFLAGS_IF) != 0;
+	kvm_run->flags = is_smm(vcpu) ? KVM_RUN_X86_SMM : 0;
 	kvm_run->cr8 = kvm_get_cr8(vcpu);
 	kvm_run->apic_base = kvm_get_apic_base(vcpu);
 	if (irqchip_in_kernel(vcpu->kvm))

include/uapi/linux/kvm.h

@@ -202,7 +202,7 @@ struct kvm_run {
 	__u32 exit_reason;
 	__u8 ready_for_interrupt_injection;
 	__u8 if_flag;
-	__u8 padding2[2];
+	__u16 flags;
 
 	/* in (pre_kvm_run), out (post_kvm_run) */
 	__u64 cr8;
@@ -815,6 +815,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_S390_IRQ_STATE 114
 #define KVM_CAP_PPC_HWRNG 115
 #define KVM_CAP_DISABLE_QUIRKS 116
+#define KVM_CAP_X86_SMM 117
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -1200,6 +1201,8 @@ struct kvm_s390_ucas_mapping {
 /* Available with KVM_CAP_S390_IRQ_STATE */
 #define KVM_S390_SET_IRQ_STATE	  _IOW(KVMIO, 0xb5, struct kvm_s390_irq_state)
 #define KVM_S390_GET_IRQ_STATE	  _IOW(KVMIO, 0xb6, struct kvm_s390_irq_state)
+/* Available with KVM_CAP_X86_SMM */
+#define KVM_SMI                   _IO(KVMIO,   0xb7)
 
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)
 #define KVM_DEV_ASSIGN_PCI_2_3		(1 << 1)