From 59073aaf6de0d2dacc2603cee6d1d6cd5592ac08 Mon Sep 17 00:00:00 2001 From: Jim Mattson Date: Tue, 16 Oct 2018 14:29:20 -0700 Subject: [PATCH] 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 Suggested-by: Paolo Bonzini Signed-off-by: Jim Mattson Signed-off-by: Paolo Bonzini --- Documentation/virtual/kvm/api.txt | 24 ++++++++--- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/include/uapi/asm/kvm.h | 7 ++- arch/x86/kvm/x86.c | 61 ++++++++++++++++++++------- tools/arch/x86/include/uapi/asm/kvm.h | 10 ++++- 5 files changed, 77 insertions(+), 26 deletions(-) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index cf9422f4f101..e900ac31501c 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -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 diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 20f7c994afeb..55e51ff7e421 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -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 { diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h index ab76aa1d3a4d..dabfcf7c3941 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -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 */ diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 532b660fe497..2ef706574589 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -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; diff --git a/tools/arch/x86/include/uapi/asm/kvm.h b/tools/arch/x86/include/uapi/asm/kvm.h index 86299efa804a..b09875f580d5 100644 --- a/tools/arch/x86/include/uapi/asm/kvm.h +++ b/tools/arch/x86/include/uapi/asm/kvm.h @@ -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 */ -- 2.30.2