Changes since v1: - Rebased to kvm/queue [KVM_CAP_SYS_HYPERV_CPUID -> 188] QEMU series using the feature: https://lists.gnu.org/archive/html/qemu-devel/2020-09/msg02017.html Original description: KVM_GET_SUPPORTED_HV_CPUID was initially implemented as a vCPU ioctl but this is not very useful when VMM is just trying to query which Hyper-V features are supported by the host prior to creating VM/vCPUs. The data in KVM_GET_SUPPORTED_HV_CPUID is mostly static with a few exceptions but it seems we can change this. Add support for KVM_GET_SUPPORTED_HV_CPUID as a system ioctl as well. QEMU specific description: In some cases QEMU needs to collect the information about which Hyper-V features are supported by KVM and pass it up the stack. For non-hyper-v features this is done with system-wide KVM_GET_SUPPORTED_CPUID/ KVM_GET_MSRS ioctls but Hyper-V specific features don't get in the output (as Hyper-V CPUIDs intersect with KVM's). In QEMU, CPU feature expansion happens before any KVM vcpus are created so KVM_GET_SUPPORTED_HV_CPUID can't be used in its current shape. Vitaly Kuznetsov (7): KVM: x86: hyper-v: Mention SynDBG CPUID leaves in api.rst KVM: x86: hyper-v: disallow configuring SynIC timers with no SynIC KVM: x86: hyper-v: make KVM_GET_SUPPORTED_HV_CPUID output independent of eVMCS enablement KVM: x86: hyper-v: always advertise HV_STIMER_DIRECT_MODE_AVAILABLE KVM: x86: hyper-v: drop now unneeded vcpu parameter from kvm_vcpu_ioctl_get_hv_cpuid() KVM: x86: hyper-v: allow KVM_GET_SUPPORTED_HV_CPUID as a system ioctl KVM: selftests: test KVM_GET_SUPPORTED_HV_CPUID as a system ioctl Documentation/virt/kvm/api.rst | 12 +-- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/hyperv.c | 30 ++++---- arch/x86/kvm/hyperv.h | 3 +- arch/x86/kvm/vmx/evmcs.c | 8 +- arch/x86/kvm/vmx/evmcs.h | 2 +- arch/x86/kvm/x86.c | 44 ++++++----- include/uapi/linux/kvm.h | 3 +- .../testing/selftests/kvm/include/kvm_util.h | 2 + tools/testing/selftests/kvm/lib/kvm_util.c | 26 +++++++ .../selftests/kvm/x86_64/hyperv_cpuid.c | 77 +++++++++---------- 11 files changed, 120 insertions(+), 89 deletions(-) -- 2.25.4
