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Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features
From: |
Alexander Graf |
Subject: |
Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features |
Date: |
Sun, 12 Sep 2010 12:06:02 +0200 |
Am 12.09.2010 um 10:01 schrieb Avi Kivity <address@hidden>:
> On 09/12/2010 09:16 AM, Alexander Graf wrote:
>>>>
>>>> Depends on which Phenom you have. A Phenom II has NRIPSAVE but the old
>>>> Phenoms don't have it. For the SVM features it is not that important
>>>> what the host hardware supports but what KVM can emulate. VMCBCLEAN can
>>>> be emulated without supporting it in the host for example.
>>> Well, let's have a phenom2 type for those new features (and any other
>>> features the phenom 2 has). What's the point of using the name of existing
>>> hardware if it doesn't match that hardware?
>> Isn't that what cpu=host is there for? I don't want to see cpu type
>> cluttering like we have it on ppc. I added the core2duo type for Mac OS X
>> guests for which those are basically the oldest supported CPUs.
>
> -cpu host is to all supported features into your guest.
> -cpu phenom is to pretend you are running on a phenom cpu. This is useful
> for a migration farm for which the greatest common denominator is a phenom.
>
> Those are separate use cases.
Exactly. And the benefit from phenom -> phenom2 is so minor that it doesn't
make sense.
>
>> For the Phenom type, I honestly don't remember why, but there was also a
>> good reason to add it. In fact, I use it today to have nested virt without
>> -cpu host on hardware that's too new for my guests.
>
> Curious, what guests balk at modern hardware but are fine with phenom?
Sles11 GA ;).
>
>> Either way, I don't think we need a phenom2 type. The features additional
>> are minor enough to not really matter and all use cases I can come up with
>> require either -cpu host (local virt) or -cpu phenom (migration).
>
> I'm fine with this (or with adding phenom2). But don't make phenom contain
> flags that real phenoms don't have.
Those were my words :).
Alex
>
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, (continued)
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, Alexander Graf, 2010/09/11
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, Joerg Roedel, 2010/09/11
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, Alexander Graf, 2010/09/11
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, Joerg Roedel, 2010/09/11
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, Alexander Graf, 2010/09/11
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, Joerg Roedel, 2010/09/11
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, Alexander Graf, 2010/09/11
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, Avi Kivity, 2010/09/12
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, Alexander Graf, 2010/09/12
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, Avi Kivity, 2010/09/12
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features,
Alexander Graf <=
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, Avi Kivity, 2010/09/12
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, Alexander Graf, 2010/09/12
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, Avi Kivity, 2010/09/12
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, Joerg Roedel, 2010/09/12
- Re: [Qemu-devel] [PATCH 2/2] qemu-kvm: Add svm cpuid features, Avi Kivity, 2010/09/12
[Qemu-devel] [PATCH 1/2] qemu-kvm: Set cpuid definition to 0 before initializing it, Joerg Roedel, 2010/09/10