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Re: [Qemu-devel] [PATCH 1/2] i386: remove the new CPUID 'PCONFIG' from I
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 1/2] i386: remove the new CPUID 'PCONFIG' from Icelake-Server CPU model |
Date: |
Fri, 21 Dec 2018 07:27:36 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 |
On 20/12/18 13:50, Robert Hoo wrote:
> On Thu, 2018-12-20 at 13:38 +0100, Paolo Bonzini wrote:
>> On 20/12/18 01:18, Robert Hoo wrote:
>>> I think the sooner, the better. Take the time window that Icelake
>>> CPU
>>> model has just shipped with QEMU 3.1.0 and is not publicly/widely
>>> used
>>> yet.
>>
>> We should still leave it in the 3.1 machine types. I've just sent a
>> patch to do the same with MPX.
>>
> I took a look your patch of "Disable MPX support on named CPU models".
> Seems you do the same as I do to PCONFIG. So you agree with my above
> patch?:-)
>
> I won't object that keep it in 3.1 machine type as you do to MPX.
Sorry Robert, I changed my mind. If no hypervisor exists that enables
PCONFIG for guests (using the PCONFIG_ENABLE processor control),
effectively no one can ever have used it. We should disable it in all
machine types and Cc qemu-stable.
In fact, the same is true for INTEL_PT, which is not supported by any
released kernel version and, even is going to be available only with a
module parameter when it will be.
This is not the same as MPX, which did work even though nobody was
probably using it.
So this series is correct and I will follow up with one for INTEL_PT;
however, this begs the question of how the patches are being tested.
Paolo
- [Qemu-devel] [PATCH 0/2] Revert exposure of PCONFIG to guest, Robert Hoo, 2018/12/19
- [Qemu-devel] [PATCH 1/2] i386: remove the new CPUID 'PCONFIG' from Icelake-Server CPU model, Robert Hoo, 2018/12/19
- Re: [Qemu-devel] [PATCH 1/2] i386: remove the new CPUID 'PCONFIG' from Icelake-Server CPU model, Daniel P . Berrangé, 2018/12/19
- Re: [Qemu-devel] [PATCH 1/2] i386: remove the new CPUID 'PCONFIG' from Icelake-Server CPU model, Robert Hoo, 2018/12/19
- Re: [Qemu-devel] [PATCH 1/2] i386: remove the new CPUID 'PCONFIG' from Icelake-Server CPU model, Paolo Bonzini, 2018/12/20
- Re: [Qemu-devel] [PATCH 1/2] i386: remove the new CPUID 'PCONFIG' from Icelake-Server CPU model, Robert Hoo, 2018/12/20
- Re: [Qemu-devel] [PATCH 1/2] i386: remove the new CPUID 'PCONFIG' from Icelake-Server CPU model, Paolo Bonzini, 2018/12/20
- Re: [Qemu-devel] [PATCH 1/2] i386: remove the new CPUID 'PCONFIG' from Icelake-Server CPU model,
Paolo Bonzini <=
- Re: [Qemu-devel] [PATCH 1/2] i386: remove the new CPUID 'PCONFIG' from Icelake-Server CPU model, Robert Hoo, 2018/12/21
- Re: [Qemu-devel] [PATCH 1/2] i386: remove the new CPUID 'PCONFIG' from Icelake-Server CPU model, Paolo Bonzini, 2018/12/21
- Re: [Qemu-devel] [PATCH 1/2] i386: remove the new CPUID 'PCONFIG' from Icelake-Server CPU model, Robert Hoo, 2018/12/21
[Qemu-devel] [PATCH 2/2] Revert "i386: Add CPUID bit for PCONFIG", Robert Hoo, 2018/12/19