From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
Eduardo Habkost <ehabkost@redhat.com>,
Jon Doron <arilou@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 0/2] KVM: x86: hyper-v: make KVM_GET_SUPPORTED_HV_CPUID more useful
Date: Mon, 12 Oct 2020 10:39:38 +0200 [thread overview]
Message-ID: <871ri37s8l.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <20200929150944.1235688-1-vkuznets@redhat.com>
Vitaly Kuznetsov <vkuznets@redhat.com> writes:
> Changes since v2:
> - Keep vCPU version of the ioctl intact but make it 'deprecated' in
> api.rst [Paolo Bonzini]
> - First two patches of v2 series already made it to kvm/queue
>
> 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 (2):
> 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 | 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 +-
> .../testing/selftests/kvm/include/kvm_util.h | 2 +
> tools/testing/selftests/kvm/lib/kvm_util.c | 26 ++++++
> .../selftests/kvm/x86_64/hyperv_cpuid.c | 87 +++++++++++--------
> 9 files changed, 123 insertions(+), 69 deletions(-)
Ping)
Still hoping this can be picked up for 5.10.
the latest QEMU patchset was posted last Friday:
https://lists.gnu.org/archive/html/qemu-devel/2020-10/msg02443.html
--
Vitaly
next prev parent reply other threads:[~2020-10-12 8:39 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-29 15:09 [PATCH v3 0/2] KVM: x86: hyper-v: make KVM_GET_SUPPORTED_HV_CPUID more useful Vitaly Kuznetsov
2020-09-29 15:09 ` [PATCH v3 1/2] KVM: x86: hyper-v: allow KVM_GET_SUPPORTED_HV_CPUID as a system ioctl Vitaly Kuznetsov
2020-09-29 15:09 ` [PATCH v3 2/2] KVM: selftests: test " Vitaly Kuznetsov
2020-10-12 8:39 ` Vitaly Kuznetsov [this message]
2020-11-06 10:19 ` [PATCH v3 0/2] KVM: x86: hyper-v: make KVM_GET_SUPPORTED_HV_CPUID more useful Paolo Bonzini
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