From c21d54f0307ff42a346294899107b570b98c47b5 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Tue, 29 Sep 2020 17:09:43 +0200 Subject: [PATCH] KVM: x86: hyper-v: allow KVM_GET_SUPPORTED_HV_CPUID as a system ioctl KVM_GET_SUPPORTED_HV_CPUID is a vCPU ioctl but its output is now independent from vCPU and in some cases VMMs may want to use it as a system ioctl instead. In particular, QEMU doesn CPU feature expansion before any vCPU gets created so KVM_GET_SUPPORTED_HV_CPUID can't be used. Convert KVM_GET_SUPPORTED_HV_CPUID to 'dual' system/vCPU ioctl with the same meaning. Signed-off-by: Vitaly Kuznetsov Message-Id: <20200929150944.1235688-2-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini --- Documentation/virt/kvm/api.rst | 16 ++++++++++----- arch/x86/kvm/hyperv.c | 6 +++--- arch/x86/kvm/hyperv.h | 4 ++-- arch/x86/kvm/vmx/evmcs.c | 3 +-- arch/x86/kvm/x86.c | 45 +++++++++++++++++++++++++----------------- include/uapi/linux/kvm.h | 3 ++- 6 files changed, 46 insertions(+), 31 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index e00a66d72372..81d54fe76a2d 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -4455,9 +4455,9 @@ that KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is present. 4.118 KVM_GET_SUPPORTED_HV_CPUID -------------------------------- -:Capability: KVM_CAP_HYPERV_CPUID +:Capability: KVM_CAP_HYPERV_CPUID (vcpu), KVM_CAP_SYS_HYPERV_CPUID (system) :Architectures: x86 -:Type: vcpu ioctl +:Type: system ioctl, vcpu ioctl :Parameters: struct kvm_cpuid2 (in/out) :Returns: 0 on success, -1 on error @@ -4502,9 +4502,6 @@ Currently, the following list of CPUID leaves are returned: - HYPERV_CPUID_SYNDBG_INTERFACE - HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES -HYPERV_CPUID_NESTED_FEATURES leaf is only exposed when Enlightened VMCS was -enabled on the corresponding vCPU (KVM_CAP_HYPERV_ENLIGHTENED_VMCS). - Userspace invokes KVM_GET_SUPPORTED_HV_CPUID by passing a kvm_cpuid2 structure with the 'nent' field indicating the number of entries in the variable-size array 'entries'. If the number of entries is too low to describe all Hyper-V @@ -4515,6 +4512,15 @@ number of valid entries in the 'entries' array, which is then filled. 'index' and 'flags' fields in 'struct kvm_cpuid_entry2' are currently reserved, userspace should not expect to get any particular value there. +Note, vcpu version of KVM_GET_SUPPORTED_HV_CPUID is currently deprecated. Unlike +system ioctl which exposes all supported feature bits unconditionally, vcpu +version has the following quirks: +- HYPERV_CPUID_NESTED_FEATURES leaf and HV_X64_ENLIGHTENED_VMCS_RECOMMENDED + feature bit are only exposed when Enlightened VMCS was previously enabled + on the corresponding vCPU (KVM_CAP_HYPERV_ENLIGHTENED_VMCS). +- HV_STIMER_DIRECT_MODE_AVAILABLE bit is only exposed with in-kernel LAPIC. + (presumes KVM_CREATE_IRQCHIP has already been called). + 4.119 KVM_ARM_VCPU_FINALIZE --------------------------- diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 5c7c4060b45c..922c69dcca4d 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1951,8 +1951,8 @@ int kvm_vm_ioctl_hv_eventfd(struct kvm *kvm, struct kvm_hyperv_eventfd *args) return kvm_hv_eventfd_assign(kvm, args->conn_id, args->fd); } -int kvm_vcpu_ioctl_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, - struct kvm_cpuid_entry2 __user *entries) +int kvm_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, + struct kvm_cpuid_entry2 __user *entries) { uint16_t evmcs_ver = 0; struct kvm_cpuid_entry2 cpuid_entries[] = { @@ -2037,7 +2037,7 @@ int kvm_vcpu_ioctl_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, * Direct Synthetic timers only make sense with in-kernel * LAPIC */ - if (lapic_in_kernel(vcpu)) + if (!vcpu || lapic_in_kernel(vcpu)) ent->edx |= HV_STIMER_DIRECT_MODE_AVAILABLE; break; diff --git a/arch/x86/kvm/hyperv.h b/arch/x86/kvm/hyperv.h index e68c6c2e9649..6d7def2b0aad 100644 --- a/arch/x86/kvm/hyperv.h +++ b/arch/x86/kvm/hyperv.h @@ -126,7 +126,7 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm, void kvm_hv_init_vm(struct kvm *kvm); void kvm_hv_destroy_vm(struct kvm *kvm); int kvm_vm_ioctl_hv_eventfd(struct kvm *kvm, struct kvm_hyperv_eventfd *args); -int kvm_vcpu_ioctl_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, - struct kvm_cpuid_entry2 __user *entries); +int kvm_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, + struct kvm_cpuid_entry2 __user *entries); #endif diff --git a/arch/x86/kvm/vmx/evmcs.c b/arch/x86/kvm/vmx/evmcs.c index f3199bb02f22..41f24661af04 100644 --- a/arch/x86/kvm/vmx/evmcs.c +++ b/arch/x86/kvm/vmx/evmcs.c @@ -326,7 +326,6 @@ bool nested_enlightened_vmentry(struct kvm_vcpu *vcpu, u64 *evmcs_gpa) uint16_t nested_get_evmcs_version(struct kvm_vcpu *vcpu) { - struct vcpu_vmx *vmx = to_vmx(vcpu); /* * vmcs_version represents the range of supported Enlightened VMCS * versions: lower 8 bits is the minimal version, higher 8 bits is the @@ -334,7 +333,7 @@ uint16_t nested_get_evmcs_version(struct kvm_vcpu *vcpu) * KVM_EVMCS_VERSION. */ if (kvm_cpu_cap_get(X86_FEATURE_VMX) && - vmx->nested.enlightened_vmcs_enabled) + (!vcpu || to_vmx(vcpu)->nested.enlightened_vmcs_enabled)) return (KVM_EVMCS_VERSION << 8) | 1; return 0; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 2db86702cac4..773cb52cb775 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3677,6 +3677,27 @@ static inline bool kvm_can_mwait_in_guest(void) boot_cpu_has(X86_FEATURE_ARAT); } +static int kvm_ioctl_get_supported_hv_cpuid(struct kvm_vcpu *vcpu, + struct kvm_cpuid2 __user *cpuid_arg) +{ + struct kvm_cpuid2 cpuid; + int r; + + r = -EFAULT; + if (copy_from_user(&cpuid, cpuid_arg, sizeof(cpuid))) + return r; + + r = kvm_get_hv_cpuid(vcpu, &cpuid, cpuid_arg->entries); + if (r) + return r; + + r = -EFAULT; + if (copy_to_user(cpuid_arg, &cpuid, sizeof(cpuid))) + return r; + + return 0; +} + int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) { int r = 0; @@ -3713,6 +3734,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_HYPERV_TLBFLUSH: case KVM_CAP_HYPERV_SEND_IPI: case KVM_CAP_HYPERV_CPUID: + case KVM_CAP_SYS_HYPERV_CPUID: case KVM_CAP_PCI_SEGMENT: case KVM_CAP_DEBUGREGS: case KVM_CAP_X86_ROBUST_SINGLESTEP: @@ -3898,6 +3920,9 @@ long kvm_arch_dev_ioctl(struct file *filp, case KVM_GET_MSRS: r = msr_io(NULL, argp, do_get_msr_feature, 1); break; + case KVM_GET_SUPPORTED_HV_CPUID: + r = kvm_ioctl_get_supported_hv_cpuid(NULL, argp); + break; default: r = -EINVAL; break; @@ -4974,25 +4999,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp, srcu_read_unlock(&vcpu->kvm->srcu, idx); break; } - case KVM_GET_SUPPORTED_HV_CPUID: { - struct kvm_cpuid2 __user *cpuid_arg = argp; - struct kvm_cpuid2 cpuid; - - r = -EFAULT; - if (copy_from_user(&cpuid, cpuid_arg, sizeof(cpuid))) - goto out; - - r = kvm_vcpu_ioctl_get_hv_cpuid(vcpu, &cpuid, - cpuid_arg->entries); - if (r) - goto out; - - r = -EFAULT; - if (copy_to_user(cpuid_arg, &cpuid, sizeof(cpuid))) - goto out; - r = 0; + case KVM_GET_SUPPORTED_HV_CPUID: + r = kvm_ioctl_get_supported_hv_cpuid(vcpu, argp); break; - } default: r = -EINVAL; } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index ca41220b40b8..204afbe1240e 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1053,6 +1053,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_X86_USER_SPACE_MSR 188 #define KVM_CAP_X86_MSR_FILTER 189 #define KVM_CAP_ENFORCE_PV_FEATURE_CPUID 190 +#define KVM_CAP_SYS_HYPERV_CPUID 191 #ifdef KVM_CAP_IRQ_ROUTING @@ -1511,7 +1512,7 @@ struct kvm_enc_region { /* Available with KVM_CAP_MANUAL_DIRTY_LOG_PROTECT_2 */ #define KVM_CLEAR_DIRTY_LOG _IOWR(KVMIO, 0xc0, struct kvm_clear_dirty_log) -/* Available with KVM_CAP_HYPERV_CPUID */ +/* Available with KVM_CAP_HYPERV_CPUID (vcpu) / KVM_CAP_SYS_HYPERV_CPUID (system) */ #define KVM_GET_SUPPORTED_HV_CPUID _IOWR(KVMIO, 0xc1, struct kvm_cpuid2) /* Available with KVM_CAP_ARM_SVE */ -- 2.11.0