Re: [Qemu-devel] [PATCH 1/2] KVM: Add new -cpu best

[Alexander Graf]

On 09.01.2012, at 01:02, Peter Maydell wrote:

> On 8 January 2012 23:52, Alexander Graf <address@hidden> wrote:
>> During discussions on whether to make -cpu host the default in SLE, I found
>> myself disagreeing to the thought, because it potentially opens a big can
>> of worms for potential bugs. But if I already am so opposed to it for SLE, 
>> how
>> can it possibly be reasonable to default to -cpu host in upstream QEMU? And
>> what would a sane default look like?
>> 
>> So I had this idea of looping through all available CPU definitions. We can
>> pretty well tell if our host is able to execute any of them by checking the
>> respective flags and seeing if our host has all features the CPU definition
>> requires. With that, we can create a -cpu type that would fall back to the
>> "best known CPU definition" that our host can fulfill. On my Phenom II
>> system for example, that would be -cpu phenom.
> 
> ...shouldn't this be supported on at least all hosts with KVM support,
> not just x86?

I don't think it makes sense on any other platform. For PPC -cpu host is good 
enough, since it's basically doing the same as -cpu best. We only have a single 
32 bit number as identifier for -cpu host there.

> Also I don't see any documentation updates in this patchset :-)

Do we have documentation for -cpu host?


Alex