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From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>,
	Igor Mammedov <imammedo@redhat.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 0/4] KVM: x86: Partially allow KVM_SET_CPUID{,2} after KVM_RUN for CPU hotplug
Date: Mon, 17 Jan 2022 16:05:38 +0100	[thread overview]
Message-ID: <20220117150542.2176196-1-vkuznets@redhat.com> (raw)

Changes since v1:
- Drop the allowlist of items which were allowed to change and just allow
the exact same CPUID data [Sean, Paolo]. Adjust selftest accordingly.
- Drop PATCH1 as the exact same change got merged upstream.

Recently, KVM made it illegal to change CPUID after KVM_RUN but
unfortunately this change is not fully compatible with existing VMMs.
In particular, QEMU reuses vCPU fds for CPU hotplug after unplug and it
calls KVM_SET_CPUID2. Relax the requirement by implementing an allowing
KVM_SET_CPUID{,2} with the exact same data.

Vitaly Kuznetsov (4):
  KVM: x86: Do runtime CPUID update before updating
    vcpu->arch.cpuid_entries
  KVM: x86: Partially allow KVM_SET_CPUID{,2} after KVM_RUN
  KVM: selftests: Rename 'get_cpuid_test' to 'cpuid_test'
  KVM: selftests: Test KVM_SET_CPUID2 after KVM_RUN

 arch/x86/kvm/cpuid.c                          | 67 ++++++++++++++++---
 arch/x86/kvm/x86.c                            | 19 ------
 tools/testing/selftests/kvm/.gitignore        |  2 +-
 tools/testing/selftests/kvm/Makefile          |  4 +-
 .../selftests/kvm/include/x86_64/processor.h  |  7 ++
 .../selftests/kvm/lib/x86_64/processor.c      | 33 +++++++--
 .../x86_64/{get_cpuid_test.c => cpuid_test.c} | 30 +++++++++
 7 files changed, 126 insertions(+), 36 deletions(-)
 rename tools/testing/selftests/kvm/x86_64/{get_cpuid_test.c => cpuid_test.c} (83%)

-- 
2.34.1


             reply	other threads:[~2022-01-17 15:05 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-17 15:05 Vitaly Kuznetsov [this message]
2022-01-17 15:05 ` [PATCH v2 1/4] KVM: x86: Do runtime CPUID update before updating vcpu->arch.cpuid_entries Vitaly Kuznetsov
2022-01-17 15:05 ` [PATCH v2 2/4] KVM: x86: Partially allow KVM_SET_CPUID{,2} after KVM_RUN Vitaly Kuznetsov
2022-01-17 17:30   ` Paolo Bonzini
2022-01-18  8:40     ` Vitaly Kuznetsov
2022-01-18 14:37       ` Vitaly Kuznetsov
2022-01-17 15:05 ` [PATCH v2 3/4] KVM: selftests: Rename 'get_cpuid_test' to 'cpuid_test' Vitaly Kuznetsov
2022-01-17 15:05 ` [PATCH v2 4/4] KVM: selftests: Test KVM_SET_CPUID2 after KVM_RUN Vitaly Kuznetsov
2022-01-18 14:35 ` [PATCH v2 0/4] KVM: x86: Partially allow KVM_SET_CPUID{,2} after KVM_RUN for CPU hotplug Igor Mammedov
2022-01-18 16:17   ` Paolo Bonzini
2022-01-18 16:53     ` Sean Christopherson
2022-01-18 17:12       ` Paolo Bonzini
2022-01-18 16:34   ` Vitaly Kuznetsov
2022-01-19  7:59     ` Igor Mammedov

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