KVM: x86: Check for CPUID 0xD.N support before validating array size

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Now that sub-leaf 1 is handled separately, verify the next sub-leaf is
needed before rejecting KVM_GET_SUPPORTED_CPUID due to an insufficiently
sized userspace array.

Note, although this is technically a bug, it's not visible to userspace
as KVM_GET_SUPPORTED_CPUID is guaranteed to fail on KVM_CPUID_SIGNATURE,
which is hardcoded to be added after leaf 0xD.  The real motivation for
the change is to tightly couple the nent/maxnent and do_host_cpuid()
sequences in preparation for future cleanup.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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Sean Christopherson 2020-03-02 15:56:10 -08:00 • committed by Paolo Bonzini

parent 3dc4a9cf05

commit 1893c9415a

1 changed files with 3 additions and 2 deletions

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arch/x86/kvm/cpuid.c

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