Re: [Qemu-devel] [Qemu-ppc] [PATCH 4/5] target-ppc: Synchronize FPU state with KVM

[Alexander Graf]

On 23.01.2013, at 23:16, Peter Maydell wrote:

> On 23 January 2013 22:05, David Gibson <address@hidden> wrote:
>> On Wed, Jan 23, 2013 at 11:56:04AM -0600, Scott Wood wrote:
>>> I don't see where you check a capability, so users of pre-one-reg
>>> KVM now get (at least) 33 warning messages every time context gets
>>> synchronized?
>> 
>> Given that a bunch of important state is missing from that
>> synchronization, I think a slew of warnings is entirely appropriate.
>> There are no per-register capabilities so there's nothing we can check
>> here.
> 
> FWIW, I think the correct way to detect whether KVM_GET/SET_ONE_REG
> supports a particular register or set of registers is to use
> KVM_GET_REG_LIST. I don't know if PPC KVM implements that ioctl yet,
> though (it may be new with ARM KVM's extensive use of GET/SET_ONE_REG).

No, we don't support it yet. The idea is that you poke GET/SET_ONE_REG and if 
that returns -EINVAL, you know that it's not supported. I figured back then 
that this is enough of a test if you know the REGs you want to poke.


Alex