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: [PATCH v4 0/2] KVM: x86: hyper-v: make KVM_GET_SUPPORTED_HV_CPUID more useful
Date: Mon, 26 Oct 2020 17:30:11 +0100 [thread overview]
Message-ID: <20201026163013.3164236-1-vkuznets@redhat.com> (raw)
Changes since v3:
- Rebase to the latest kvm/queue (KVM_CAP_SYS_HYPERV_CPUID changed to 191)
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(-)
--
2.25.4
next reply other threads:[~2020-10-26 16:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-26 16:30 Vitaly Kuznetsov [this message]
2020-10-26 16:30 ` [PATCH v4 1/2] KVM: x86: hyper-v: allow KVM_GET_SUPPORTED_HV_CPUID as a system ioctl Vitaly Kuznetsov
2020-10-26 16:30 ` [PATCH v4 2/2] KVM: selftests: test " Vitaly Kuznetsov
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