Re: [PATCH] KVM: x86: fix bogus warning about reserved bits

From	Paolo Bonzini <pbonzini@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] KVM: x86: fix bogus warning about reserved bits
Date	2015-09-25 10:00 +0200
Message-ID	<qcw5c-3AI-17@gated-at.bofh.it> (permalink)
References	(2 earlier) <qbCZ3-af-1@gated-at.bofh.it> <qbN85-6jv-1@gated-at.bofh.it> <qbOGR-bd-25@gated-at.bofh.it> <qc5om-7HZ-23@gated-at.bofh.it> <qcbN8-8v1-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 24/09/2015 12:12, Borislav Petkov wrote:
> On Thu, Sep 24, 2015 at 11:23:08AM +0800, Xiao Guangrong wrote:
>>> +static inline bool
>>> +boot_cpu_is_amd(void)
>>> +{
>>> +	WARN_ON_ONCE(!tdp_enabled);
>>> +	return shadow_x_mask != 0;
>>
>> shadow_x_mask != 0 is Intel's CPU.
>>
>> Borislav, could you please check shadow_x_mask == 0 instead and test it again?
> 
> That did the trick:
> 
> [   62.640392] kvm: zapping shadow pages for mmio generation wraparound
> [   63.100301] cpuid(0).ebx = 68747541
> [   63.193426] kvm [3748]: vcpu0 unhandled rdmsr: 0xc0010112
> [   64.538294] kvm [3748]: vcpu0 unhandled rdmsr: 0xc0011021
> [   64.866263] kvm [3748]: vcpu1 unhandled rdmsr: 0xc0011021
> [   64.971972] kvm [3748]: vcpu2 unhandled rdmsr: 0xc0011021
> [   65.070376] kvm [3748]: vcpu3 unhandled rdmsr: 0xc0011021
> [   65.170625] kvm [3748]: vcpu4 unhandled rdmsr: 0xc0011021
> [   65.272838] kvm [3748]: vcpu5 unhandled rdmsr: 0xc0011021
> [   65.374288] kvm [3748]: vcpu6 unhandled rdmsr: 0xc0011021
> [   65.474825] kvm [3748]: vcpu7 unhandled rdmsr: 0xc0011021
> 
> That's all I got in dmesg from booting the guest - no more mmio PF
> warnings.

Great, though this doesn't yet explain why guest_cpuid_is_amd failed.
I'll look into it next week when Amazon delivers my shiny new AMD
mini-PC :) and send the patch to Linus meanwhile.

Paolo
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Thread

Re: [PATCH] KVM: x86: fix bogus warning about reserved bits Borislav Petkov <bp@alien8.de> - 2015-09-22 20:00 +0200
  Re: [PATCH] KVM: x86: fix bogus warning about reserved bits Paolo Bonzini <pbonzini@redhat.com> - 2015-09-22 23:10 +0200
    Re: [PATCH] KVM: x86: fix bogus warning about reserved bits Borislav Petkov <bp@alien8.de> - 2015-09-23 10:00 +0200
      Re: [PATCH] KVM: x86: fix bogus warning about reserved bits Paolo Bonzini <pbonzini@redhat.com> - 2015-09-23 10:40 +0200
      Re: [PATCH] KVM: x86: fix bogus warning about reserved bits Paolo Bonzini <pbonzini@redhat.com> - 2015-09-23 11:40 +0200
        Re: [PATCH] KVM: x86: fix bogus warning about reserved bits Borislav Petkov <bp@alien8.de> - 2015-09-23 13:10 +0200
          Re: [PATCH] KVM: x86: fix bogus warning about reserved bits Paolo Bonzini <pbonzini@redhat.com> - 2015-09-23 15:00 +0200
        Re: [PATCH] KVM: x86: fix bogus warning about reserved bits Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2015-09-24 05:30 +0200
          Re: [PATCH] KVM: x86: fix bogus warning about reserved bits Borislav Petkov <bp@alien8.de> - 2015-09-24 12:20 +0200
            Re: [PATCH] KVM: x86: fix bogus warning about reserved bits Paolo Bonzini <pbonzini@redhat.com> - 2015-09-25 10:00 +0200
              Re: [PATCH] KVM: x86: fix bogus warning about reserved bits Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2015-09-28 05:30 +0200

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