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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: Jim Mattson <jmattson@google.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Jim Mattson 2018-10-16 14:29:20 -07:00 committed by Paolo Bonzini
parent c851436a34
commit 59073aaf6d
5 changed files with 77 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
Documentation/virtual/kvm/api.txt
View File

@ -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

1
arch/x86/include/asm/kvm_host.h
View File

@ -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 {

7
arch/x86/include/uapi/asm/kvm.h
View File

@ -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 */

61
arch/x86/kvm/x86.c
View File

@ -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);
/*
* 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.
* 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.
*/
events->exception.injected =
(vcpu->arch.exception.pending ||
vcpu->arch.exception.injected) &&
!kvm_exception_is_soft(vcpu->arch.exception.nr);
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;
/*
* 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->exception.injected &&
(events->exception.nr > 31 || events->exception.nr == NMI_VECTOR ||
is_guest_mode(vcpu)))
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.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;

10
tools/arch/x86/include/uapi/asm/kvm.h
View File

@ -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;
__u8 pad;
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 */