From: Jan Kiszka <[email protected]> User space may not want to overwrite asynchronously changing VCPU event states on write-back. So allow to skip nmi.pending and sipi_vector by setting corresponding bits in the flags field of kvm_vcpu_events.
[avi: advertise the bits in KVM_GET_VCPU_EVENTS] Signed-off-by: Jan Kiszka <[email protected]> Signed-off-by: Avi Kivity <[email protected]> diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt index e1a1141..b22592d 100644 --- a/Documentation/kvm/api.txt +++ b/Documentation/kvm/api.txt @@ -685,7 +685,7 @@ struct kvm_vcpu_events { __u8 pad; } nmi; __u32 sipi_vector; - __u32 flags; /* must be zero */ + __u32 flags; }; 4.30 KVM_SET_VCPU_EVENTS @@ -701,6 +701,14 @@ 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: + +KVM_VCPUEVENT_SET_NMI_PENDING - transfer nmi.pending to the kernel +KVM_VCPUEVENT_SET_SIPI_VECTOR - transfer sipi_vector + 5. The kvm_run structure diff --git a/arch/x86/include/asm/kvm.h b/arch/x86/include/asm/kvm.h index 950df43..d1a67ae 100644 --- a/arch/x86/include/asm/kvm.h +++ b/arch/x86/include/asm/kvm.h @@ -254,6 +254,10 @@ struct kvm_reinject_control { __u8 reserved[31]; }; +/* When set in flags, include corresponding fields on KVM_SET_VCPU_EVENTS */ +#define KVM_VCPUEVENT_SET_NMI_PENDING 0x00000001 +#define KVM_VCPUEVENT_SET_SIPI_VECTOR 0x00000002 + /* for KVM_GET/SET_VCPU_EVENTS */ struct kvm_vcpu_events { struct { diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4a16337..e181c6f 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1945,7 +1945,8 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu, events->sipi_vector = vcpu->arch.sipi_vector; - events->flags = 0; + events->flags = (KVM_VCPUEVENT_SET_NMI_PENDING + | KVM_VCPUEVENT_SET_SIPI_VECTOR); vcpu_put(vcpu); } @@ -1953,7 +1954,8 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu, static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu, struct kvm_vcpu_events *events) { - if (events->flags) + if (events->flags & + ~(KVM_VCPUEVENT_SET_NMI_PENDING | KVM_VCPUEVENT_SET_SIPI_VECTOR)) return -EINVAL; vcpu_load(vcpu); @@ -1970,10 +1972,12 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu, kvm_pic_clear_isr_ack(vcpu->kvm); vcpu->arch.nmi_injected = events->nmi.injected; - vcpu->arch.nmi_pending = events->nmi.pending; + if (events->flags & KVM_VCPUEVENT_SET_NMI_PENDING) + vcpu->arch.nmi_pending = events->nmi.pending; kvm_x86_ops->set_nmi_mask(vcpu, events->nmi.masked); - vcpu->arch.sipi_vector = events->sipi_vector; + if (events->flags & KVM_VCPUEVENT_SET_SIPI_VECTOR) + vcpu->arch.sipi_vector = events->sipi_vector; vcpu_put(vcpu); -- To unsubscribe from this list: send the line "unsubscribe kvm-commits" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
