Commit 59073aaf authored by Jim Mattson's avatar Jim Mattson Committed by Paolo Bonzini
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kvm: x86: Add exception payload fields to kvm_vcpu_events 



The per-VM capability KVM_CAP_EXCEPTION_PAYLOAD (to be introduced in a
later commit) adds the following fields to struct kvm_vcpu_events:
exception_has_payload, exception_payload, and exception.pending.

With this capability set, all of the details of vcpu->arch.exception,
including the payload for a pending exception, are reported to
userspace in response to KVM_GET_VCPU_EVENTS.

With this capability clear, the original ABI is preserved, and the
exception.injected field is set for either pending or injected
exceptions.

When userspace calls KVM_SET_VCPU_EVENTS with
KVM_CAP_EXCEPTION_PAYLOAD clear, exception.injected is no longer
translated to exception.pending. KVM_SET_VCPU_EVENTS can now only
establish a pending exception when KVM_CAP_EXCEPTION_PAYLOAD is set.

Reported-by: default avatarJim Mattson <jmattson@google.com>
Suggested-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarJim Mattson <jmattson@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent c851436a

Documentation/virtual/kvm/api.txt

+18 −6
Original line number Diff line number Diff line
@@ -850,7 +850,7 @@ struct kvm_vcpu_events { 
		__u8 injected;

		__u8 nr;

		__u8 has_error_code;

		__u8 pad;

		__u8 pending;

		__u32 error_code;

	} exception;

	struct {
@@ -873,16 +873,23 @@ struct kvm_vcpu_events { 
		__u8 smm_inside_nmi;

		__u8 latched_init;

	} smi;

	__u32 reserved[9];

	__u8 reserved[27];

	__u8 exception_has_payload;

	__u64 exception_payload;

};



Only two fields are defined in the flags field:

The following bits are defined in the flags field:



- KVM_VCPUEVENT_VALID_SHADOW may be set in the flags field to signal that

- KVM_VCPUEVENT_VALID_SHADOW may be set 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.

- KVM_VCPUEVENT_VALID_SMM may be set to signal that smi contains a

  valid state.



- KVM_VCPUEVENT_VALID_PAYLOAD may be set to signal that the

  exception_has_payload, exception_payload, and exception.pending

  fields contain a valid state. This bit will be set whenever

  KVM_CAP_EXCEPTION_PAYLOAD is enabled.



ARM/ARM64:
@@ -962,6 +969,11 @@ shall be written into the VCPU. 


KVM_VCPUEVENT_VALID_SMM can only be set if KVM_CAP_X86_SMM is available.



If KVM_CAP_EXCEPTION_PAYLOAD is enabled, KVM_VCPUEVENT_VALID_PAYLOAD

can be set in the flags field to signal that the

exception_has_payload, exception_payload, and exception.pending fields

contain a valid state and shall be written into the VCPU.



ARM/ARM64:



Set the pending SError exception state for this VCPU. It is not possible to

arch/x86/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -919,6 +919,7 @@ struct kvm_arch { 
	bool x2apic_broadcast_quirk_disabled;



	bool guest_can_read_msr_platform_info;

	bool exception_payload_enabled;

};



struct kvm_vm_stat {

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

+5 −2
Original line number Diff line number Diff line
@@ -288,6 +288,7 @@ struct kvm_reinject_control { 
#define KVM_VCPUEVENT_VALID_SIPI_VECTOR	0x00000002

#define KVM_VCPUEVENT_VALID_SHADOW	0x00000004

#define KVM_VCPUEVENT_VALID_SMM		0x00000008

#define KVM_VCPUEVENT_VALID_PAYLOAD	0x00000010



/* Interrupt shadow states */

#define KVM_X86_SHADOW_INT_MOV_SS	0x01
@@ -299,7 +300,7 @@ struct kvm_vcpu_events { 
		__u8 injected;

		__u8 nr;

		__u8 has_error_code;

		__u8 pad;

		__u8 pending;

		__u32 error_code;

	} exception;

	struct {
@@ -322,7 +323,9 @@ struct kvm_vcpu_events { 
		__u8 smm_inside_nmi;

		__u8 latched_init;

	} smi;

	__u32 reserved[9];

	__u8 reserved[27];

	__u8 exception_has_payload;

	__u64 exception_payload;

};



/* for KVM_GET/SET_DEBUGREGS */

arch/x86/kvm/x86.c

+45 −16
Original line number Diff line number Diff line
@@ -3373,19 +3373,33 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu, 
					       struct kvm_vcpu_events *events)

{

	process_nmi(vcpu);



	/*

	 * The API doesn't provide the instruction length for software

	 * exceptions, so don't report them. As long as the guest RIP

	 * isn't advanced, we should expect to encounter the exception

	 * again.

	 */

	if (kvm_exception_is_soft(vcpu->arch.exception.nr)) {

		events->exception.injected = 0;

		events->exception.pending = 0;

	} else {

		events->exception.injected = vcpu->arch.exception.injected;

		events->exception.pending = vcpu->arch.exception.pending;

		/*

	 * FIXME: pass injected and pending separately.  This is only

	 * needed for nested virtualization, whose state cannot be

	 * migrated yet.  For now we can combine them.

	 */

	events->exception.injected =

		(vcpu->arch.exception.pending ||

		 vcpu->arch.exception.injected) &&

		!kvm_exception_is_soft(vcpu->arch.exception.nr);

		 * For ABI compatibility, deliberately conflate

		 * pending and injected exceptions when

		 * KVM_CAP_EXCEPTION_PAYLOAD isn't enabled.

		 */

		if (!vcpu->kvm->arch.exception_payload_enabled)

			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.pad = 0;

	events->exception.error_code = vcpu->arch.exception.error_code;

	events->exception_has_payload = vcpu->arch.exception.has_payload;

	events->exception_payload = vcpu->arch.exception.payload;



	events->interrupt.injected =

		vcpu->arch.interrupt.injected && !vcpu->arch.interrupt.soft;
@@ -3409,6 +3423,9 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu, 
	events->flags = (KVM_VCPUEVENT_VALID_NMI_PENDING

			 | KVM_VCPUEVENT_VALID_SHADOW

			 | KVM_VCPUEVENT_VALID_SMM);

	if (vcpu->kvm->arch.exception_payload_enabled)

		events->flags |= KVM_VCPUEVENT_VALID_PAYLOAD;



	memset(&events->reserved, 0, sizeof(events->reserved));

}
@@ -3420,12 +3437,24 @@ 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_SMM))

			      | KVM_VCPUEVENT_VALID_SMM

			      | KVM_VCPUEVENT_VALID_PAYLOAD))

		return -EINVAL;



	if (events->flags & KVM_VCPUEVENT_VALID_PAYLOAD) {

		if (!vcpu->kvm->arch.exception_payload_enabled)

			return -EINVAL;

		if (events->exception.pending)

			events->exception.injected = 0;

		else

			events->exception_has_payload = 0;

	} else {

		events->exception.pending = 0;

		events->exception_has_payload = 0;

	}



	if (events->exception.injected &&

	    (events->exception.nr > 31 || events->exception.nr == NMI_VECTOR ||

	     is_guest_mode(vcpu)))

	if ((events->exception.injected || events->exception.pending) &&

	    (events->exception.nr > 31 || events->exception.nr == NMI_VECTOR))

		return -EINVAL;



	/* INITs are latched while in SMM */
@@ -3435,13 +3464,13 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu, 
		return -EINVAL;



	process_nmi(vcpu);

	vcpu->arch.exception.injected = false;

	vcpu->arch.exception.pending = events->exception.injected;

	vcpu->arch.exception.injected = events->exception.injected;

	vcpu->arch.exception.pending = events->exception.pending;

	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.exception.has_payload = false;

	vcpu->arch.exception.payload = 0;

	vcpu->arch.exception.has_payload = events->exception_has_payload;

	vcpu->arch.exception.payload = events->exception_payload;



	vcpu->arch.interrupt.injected = events->interrupt.injected;

	vcpu->arch.interrupt.nr = events->interrupt.nr;

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

+8 −2
Original line number Diff line number Diff line
@@ -288,6 +288,7 @@ struct kvm_reinject_control { 
#define KVM_VCPUEVENT_VALID_SIPI_VECTOR	0x00000002

#define KVM_VCPUEVENT_VALID_SHADOW	0x00000004

#define KVM_VCPUEVENT_VALID_SMM		0x00000008

#define KVM_VCPUEVENT_VALID_PAYLOAD	0x00000010



/* Interrupt shadow states */

#define KVM_X86_SHADOW_INT_MOV_SS	0x01
@@ -299,7 +300,10 @@ struct kvm_vcpu_events { 
		__u8 injected;

		__u8 nr;

		__u8 has_error_code;

		union {

			__u8 pad;

			__u8 pending;

		};

		__u32 error_code;

	} exception;

	struct {
@@ -322,7 +326,9 @@ struct kvm_vcpu_events { 
		__u8 smm_inside_nmi;

		__u8 latched_init;

	} smi;

	__u32 reserved[9];

	__u8 reserved[27];

	__u8 exception_has_payload;

	__u64 exception_payload;

};



/* for KVM_GET/SET_DEBUGREGS */

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