KVM: x86: Add support for RDPID without RDTSCP

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Allow userspace to enable RDPID for a guest without also enabling RDTSCP.
Aside from checking for RDPID support in the obvious flows, VMX also needs
to set ENABLE_RDTSCP=1 when RDPID is exposed.

For the record, there is no known scenario where enabling RDPID without
RDTSCP is desirable.  But, both AMD and Intel architectures allow for the
condition, i.e. this is purely to make KVM more architecturally accurate.

Fixes: 41cd02c6f7 ("kvm: x86: Expose RDPID in KVM_GET_SUPPORTED_CPUID")
Cc: stable@vger.kernel.org
Reported-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210504171734.1434054-8-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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Sean Christopherson 2021-05-04 10:17:26 -07:00 • committed by Paolo Bonzini

parent 0caa0a77c2

commit 36fa06f9ff

3 changed files with 29 additions and 7 deletions

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6

arch/x86/kvm/svm/svm.c

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27

arch/x86/kvm/vmx/vmx.c

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3

arch/x86/kvm/x86.c

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