Re: [PATCH 3/4] KVM: nVMX: accurate emulation of MSR_IA32_CR{0,4}_FIXED1

From	David Matlack <dmatlack@google.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 3/4] KVM: nVMX: accurate emulation of MSR_IA32_CR{0,4}_FIXED1
Date	2016-11-24 00:30 +0100
Message-ID	<sGP9f-2Vz-9@gated-at.bofh.it> (permalink)
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On Wed, Nov 23, 2016 at 2:11 PM, Paolo Bonzini <pbonzini@redhat.com> wrote:
> On 23/11/2016 23:07, David Matlack wrote:
>> A downside of this scheme is we'd have to remember to update
>> nested_vmx_cr4_fixed1_update() before giving VMs new CPUID bits. If we
>> forget, a VM could end up with different values for CR{0,4}_FIXED0 for
>> the same CPUID depending on which version of KVM you're running on.
>
> If userspace doesn't obey KVM_GET_SUPPORTED_CPUID, all bets are off
> anyway, so I don't think it's a big deal.  However, if you want to make
> it generated by userspace, that would be fine as well!

Ok let's generate them in userspace.

> That would simply entail removing this patch, wouldn't it?

Mostly. The first half of the patch (initialize from host MSRs) should stay.

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[PATCH 3/4] KVM: nVMX: accurate emulation of MSR_IA32_CR{0,4}_FIXED1 David Matlack <dmatlack@google.com> - 2016-11-23 02:20 +0100
  Re: [PATCH 3/4] KVM: nVMX: accurate emulation of  MSR_IA32_CR{0,4}_FIXED1 Paolo Bonzini <pbonzini@redhat.com> - 2016-11-23 10:10 +0100
    Re: [PATCH 3/4] KVM: nVMX: accurate emulation of MSR_IA32_CR{0,4}_FIXED1 David Matlack <dmatlack@google.com> - 2016-11-23 20:20 +0100
      Re: [PATCH 3/4] KVM: nVMX: accurate emulation of  MSR_IA32_CR{0,4}_FIXED1 Paolo Bonzini <pbonzini@redhat.com> - 2016-11-23 20:30 +0100
        Re: [PATCH 3/4] KVM: nVMX: accurate emulation of MSR_IA32_CR{0,4}_FIXED1 David Matlack <dmatlack@google.com> - 2016-11-23 23:10 +0100
          Re: [PATCH 3/4] KVM: nVMX: accurate emulation of  MSR_IA32_CR{0,4}_FIXED1 Paolo Bonzini <pbonzini@redhat.com> - 2016-11-23 23:20 +0100
            Re: [PATCH 3/4] KVM: nVMX: accurate emulation of MSR_IA32_CR{0,4}_FIXED1 David Matlack <dmatlack@google.com> - 2016-11-24 00:30 +0100

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