Re: [Qemu-devel] [RISU v2 00/11] Support for i386/x86_64 with vector extensions

[Richard Henderson]

On 5/23/19 2:03 PM, Jan Bobek wrote:
> I ran some experiments on my laptop's Intel(R) Core(TM) i5-4210U to
> find out what actually happens. This CPU supports AVX (but not
> AVX-512) and doesn't support XSAVEC, so I only looked at XSAVE and
> XSAVEOPT (XSAVES is kernel-mode only). I found out that:
> 
> 1. both XSAVE and XSAVEOPT do not include the AVX state if it is in
>    the initial configuration (not only XSAVEOPT),
> 2. return to initial configuration is not detected, i.e. the AVX state
>    is included even though it has been set to all zeros via vxorps,
> 3. the AVX state can be brought back to the initial configuration via
>    XRSTOR with the AVX component removed.

Thanks, for doing the tests.  I'm glad what I understood from my reading
matches experimental results.  :-)


r~