[06/12] KVM: x86: API changes for SMM support
diff mbox

Message ID 1431084034-8425-7-git-send-email-pbonzini@redhat.com
State New
Headers show

Commit Message

Paolo Bonzini May 8, 2015, 11:20 a.m. UTC
This patch includes changes to the external API for SMM support.
All the changes are predicated by the availability of a new
capability, KVM_CAP_X86_SMM, which is added at the end of the
patch series.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
	RFC->v1: add smi.pending and smi.rsm_unmasks_nmi fields, reduce padding
		 in struct kvm_vcpu_events; remove memset of events struct,
		 instead zero smi.pad.  KVM_CAP_X86_SMM frozen at 117.
---
 Documentation/virtual/kvm/api.txt | 40 +++++++++++++++++++++++++++++++++------
 arch/x86/include/asm/kvm_host.h   |  3 +++
 arch/x86/include/uapi/asm/kvm.h   | 11 ++++++++++-
 arch/x86/kvm/kvm_cache_regs.h     |  5 +++++
 arch/x86/kvm/x86.c                | 34 +++++++++++++++++++++++++++++++--
 include/uapi/linux/kvm.h          |  5 ++++-
 6 files changed, 88 insertions(+), 10 deletions(-)

Comments

Radim Krčmář May 21, 2015, 2:49 p.m. UTC | #1
2015-05-08 13:20+0200, Paolo Bonzini:
> diff --git a/include/uapi/linux/kvm.h b/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;

(It got lost last review and I'd really like to know ...
 what is the advantage of giving both bytes to flags?)
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Paolo Bonzini May 21, 2015, 2:59 p.m. UTC | #2
On 21/05/2015 16:49, Radim Kr?má? wrote:
> 2015-05-08 13:20+0200, Paolo Bonzini:
>> diff --git a/include/uapi/linux/kvm.h b/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;
> 
> (It got lost last review and I'd really like to know ...
>  what is the advantage of giving both bytes to flags?)

No advantage.  You just should leave padding2[1] in the middle so that
the offset of &run->padding2[0] doesn't change.  Since it's not obvious
I gave two bytes to flags, but I can do it either way.

Paolo
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Radim Krčmář May 21, 2015, 4:26 p.m. UTC | #3
2015-05-21 16:59+0200, Paolo Bonzini:
> On 21/05/2015 16:49, Radim Kr?má? wrote:
>> 2015-05-08 13:20+0200, Paolo Bonzini:
>>> diff --git a/include/uapi/linux/kvm.h b/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;
>> 
>> (It got lost last review and I'd really like to know ...
>>  what is the advantage of giving both bytes to flags?)
> 
> No advantage.  You just should leave padding2[1] in the middle so that
> the offset of &run->padding2[0] doesn't change.

I don't get that.  The position of padding should be decided by
comparing probabilities of extending 'if_flag' and 'flags'.

>                                                  Since it's not obvious
> I gave two bytes to flags, but I can do it either way.

if_flag seems to be set in stone as one bit, so I'd vote for

  __u8 flags;
  __u8 padding2;

(Or 'padding3', to prevent the same class of errors that removing it
 altogether does;  which we didn't do for other tailed padding).

For there isn't much space left in struct kvm ...
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Paolo Bonzini May 21, 2015, 9:21 p.m. UTC | #4
On 21/05/2015 18:26, Radim Kr?má? wrote:
> 2015-05-21 16:59+0200, Paolo Bonzini:
>> On 21/05/2015 16:49, Radim Kr?má? wrote:
>>> 2015-05-08 13:20+0200, Paolo Bonzini:
>>>> diff --git a/include/uapi/linux/kvm.h b/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;
>>>
>>> (It got lost last review and I'd really like to know ...
>>>  what is the advantage of giving both bytes to flags?)
>>
>> No advantage.  You just should leave padding2[1] in the middle so that
>> the offset of &run->padding2[0] doesn't change.
> 
> I don't get that.  The position of padding should be decided by
> comparing probabilities of extending 'if_flag' and 'flags'.
> 
>>                                                  Since it's not obvious
>> I gave two bytes to flags, but I can do it either way.
> 
> if_flag seems to be set in stone as one bit, so I'd vote for
> 
>   __u8 flags;
>   __u8 padding2;
> 
> (Or 'padding3', to prevent the same class of errors that removing it
>  altogether does;  which we didn't do for other tailed padding).

You're right that we didn't do it.  I'll change it to flags + padding2.

Paolo

> For there isn't much space left in struct kvm ...
> 
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Patch
diff mbox

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 695544420ff2..51523b70b6b2 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/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 pad;
+	} 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;
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 6487ffc95b0a..a1bef695dc99 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -469,6 +469,7 @@  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;
@@ -1112,6 +1113,8 @@  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
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index 2fec75e4b1e1..30100a3c1bed 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/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 pad;
+	} smi;
+	__u32 reserved[9];
 };
 
 /* for KVM_GET/SET_DEBUGREGS */
diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h
index 544076c4f44b..e1e89ee4af75 100644
--- a/arch/x86/kvm/kvm_cache_regs.h
+++ b/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
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7d311a0de84c..8015c67a6d07 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3037,6 +3037,11 @@  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)
 {
@@ -3142,8 +3147,15 @@  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.pad = 0;
+
 	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));
 }
 
@@ -3152,7 +3164,8 @@  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);
@@ -3177,6 +3190,18 @@  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;
+	}
+
 	kvm_make_request(KVM_REQ_EVENT, vcpu);
 
 	return 0;
@@ -3436,6 +3461,10 @@  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;
@@ -6118,6 +6147,7 @@  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))
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 75bd9f7fd846..eace8babd227 100644
--- a/include/uapi/linux/kvm.h
+++ b/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)