| Message ID | 20200711100434.46660-6-drjones@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: pvtime: Fixes and a new cap | expand |
On 2020-07-11 11:04, Andrew Jones wrote: > arm64 requires a vcpu fd (KVM_HAS_DEVICE_ATTR vcpu ioctl) to probe > support for steal-time. However this is unnecessary, as only a KVM > fd is required, and it complicates userspace (userspace may prefer > delaying vcpu creation until after feature probing). Introduce a cap > that can be checked instead. While x86 can already probe steal-time > support with a kvm fd (KVM_GET_SUPPORTED_CPUID), we add the cap there > too for consistency. > > Reviewed-by: Steven Price <steven.price@arm.com> > Signed-off-by: Andrew Jones <drjones@redhat.com> > --- > Documentation/virt/kvm/api.rst | 11 +++++++++++ > arch/arm64/include/asm/kvm_host.h | 1 + > arch/arm64/kvm/arm.c | 3 +++ > arch/arm64/kvm/pvtime.c | 2 +- > arch/x86/kvm/x86.c | 3 +++ > include/uapi/linux/kvm.h | 1 + > 6 files changed, 20 insertions(+), 1 deletion(-) > > diff --git a/Documentation/virt/kvm/api.rst > b/Documentation/virt/kvm/api.rst > index 3bd96c1a3962..3716d1e29771 100644 > --- a/Documentation/virt/kvm/api.rst > +++ b/Documentation/virt/kvm/api.rst > @@ -6152,3 +6152,14 @@ KVM can therefore start protected VMs. > This capability governs the KVM_S390_PV_COMMAND ioctl and the > KVM_MP_STATE_LOAD MP_STATE. KVM_SET_MP_STATE can fail for protected > guests when the state change is invalid. > + > +8.24 KVM_CAP_STEAL_TIME > +----------------------- > + > +:Architectures: arm64, x86 > + > +This capability indicates that KVM supports steal time accounting. > +When steal time accounting is supported it may be enabled with > +architecture-specific interfaces. For x86 see > +Documentation/virt/kvm/msr.rst "MSR_KVM_STEAL_TIME". For arm64 see > +Documentation/virt/kvm/devices/vcpu.rst "KVM_ARM_VCPU_PVTIME_CTRL". Maybe add something that indicates that KVM_CAP_STEAL_TIME and the architecture specific ioctl aren't allowed to disagree about the support? > diff --git a/arch/arm64/include/asm/kvm_host.h > b/arch/arm64/include/asm/kvm_host.h > index b01f52b61572..8909c840ea91 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -500,6 +500,7 @@ long kvm_hypercall_pv_features(struct kvm_vcpu > *vcpu); > gpa_t kvm_init_stolen_time(struct kvm_vcpu *vcpu); > void kvm_update_stolen_time(struct kvm_vcpu *vcpu); > > +bool kvm_arm_pvtime_supported(void); > int kvm_arm_pvtime_set_attr(struct kvm_vcpu *vcpu, > struct kvm_device_attr *attr); > int kvm_arm_pvtime_get_attr(struct kvm_vcpu *vcpu, > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index 90cb90561446..0f7f8cd2f341 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -222,6 +222,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, > long ext) > */ > r = 1; > break; > + case KVM_CAP_STEAL_TIME: > + r = kvm_arm_pvtime_supported(); > + break; > default: > r = kvm_arch_vm_ioctl_check_extension(kvm, ext); > break; > diff --git a/arch/arm64/kvm/pvtime.c b/arch/arm64/kvm/pvtime.c > index 025b5f3a97ef..468bd1ef9c7e 100644 > --- a/arch/arm64/kvm/pvtime.c > +++ b/arch/arm64/kvm/pvtime.c > @@ -73,7 +73,7 @@ gpa_t kvm_init_stolen_time(struct kvm_vcpu *vcpu) > return base; > } > > -static bool kvm_arm_pvtime_supported(void) > +bool kvm_arm_pvtime_supported(void) > { > return !!sched_info_on(); > } > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 88c593f83b28..27fc86bb28c4 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -3538,6 +3538,9 @@ int kvm_vm_ioctl_check_extension(struct kvm > *kvm, long ext) > case KVM_CAP_HYPERV_ENLIGHTENED_VMCS: > r = kvm_x86_ops.nested_ops->enable_evmcs != NULL; > break; > + case KVM_CAP_STEAL_TIME: > + r = sched_info_on(); > + break; > default: > break; > } > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index 4fdf30316582..121fb29ac004 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -1031,6 +1031,7 @@ struct kvm_ppc_resize_hpt { > #define KVM_CAP_PPC_SECURE_GUEST 181 > #define KVM_CAP_HALT_POLL 182 > #define KVM_CAP_ASYNC_PF_INT 183 > +#define KVM_CAP_STEAL_TIME 184 > > #ifdef KVM_CAP_IRQ_ROUTING Otherwise looks ok. Thanks, M.
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 3bd96c1a3962..3716d1e29771 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6152,3 +6152,14 @@ KVM can therefore start protected VMs. This capability governs the KVM_S390_PV_COMMAND ioctl and the KVM_MP_STATE_LOAD MP_STATE. KVM_SET_MP_STATE can fail for protected guests when the state change is invalid. + +8.24 KVM_CAP_STEAL_TIME +----------------------- + +:Architectures: arm64, x86 + +This capability indicates that KVM supports steal time accounting. +When steal time accounting is supported it may be enabled with +architecture-specific interfaces. For x86 see +Documentation/virt/kvm/msr.rst "MSR_KVM_STEAL_TIME". For arm64 see +Documentation/virt/kvm/devices/vcpu.rst "KVM_ARM_VCPU_PVTIME_CTRL". diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index b01f52b61572..8909c840ea91 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -500,6 +500,7 @@ long kvm_hypercall_pv_features(struct kvm_vcpu *vcpu); gpa_t kvm_init_stolen_time(struct kvm_vcpu *vcpu); void kvm_update_stolen_time(struct kvm_vcpu *vcpu); +bool kvm_arm_pvtime_supported(void); int kvm_arm_pvtime_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr); int kvm_arm_pvtime_get_attr(struct kvm_vcpu *vcpu, diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 90cb90561446..0f7f8cd2f341 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -222,6 +222,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) */ r = 1; break; + case KVM_CAP_STEAL_TIME: + r = kvm_arm_pvtime_supported(); + break; default: r = kvm_arch_vm_ioctl_check_extension(kvm, ext); break; diff --git a/arch/arm64/kvm/pvtime.c b/arch/arm64/kvm/pvtime.c index 025b5f3a97ef..468bd1ef9c7e 100644 --- a/arch/arm64/kvm/pvtime.c +++ b/arch/arm64/kvm/pvtime.c @@ -73,7 +73,7 @@ gpa_t kvm_init_stolen_time(struct kvm_vcpu *vcpu) return base; } -static bool kvm_arm_pvtime_supported(void) +bool kvm_arm_pvtime_supported(void) { return !!sched_info_on(); } diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 88c593f83b28..27fc86bb28c4 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3538,6 +3538,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_HYPERV_ENLIGHTENED_VMCS: r = kvm_x86_ops.nested_ops->enable_evmcs != NULL; break; + case KVM_CAP_STEAL_TIME: + r = sched_info_on(); + break; default: break; } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 4fdf30316582..121fb29ac004 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1031,6 +1031,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_PPC_SECURE_GUEST 181 #define KVM_CAP_HALT_POLL 182 #define KVM_CAP_ASYNC_PF_INT 183 +#define KVM_CAP_STEAL_TIME 184 #ifdef KVM_CAP_IRQ_ROUTING