Re: [PATCH v3 10/21] x86/fpu/xstate: Update xstate save function to support dynamic xstate

[Borislav Petkov]

On Wed, Dec 23, 2020 at 07:57:06AM -0800, Chang S. Bae wrote:
> copy_xregs_to_kernel() used to save all user states in a kernel buffer.
> When the dynamic user state is enabled, it becomes conditional which state
> to be saved.
> 
> fpu->state_mask can indicate which state components are reserved to be
> saved in XSAVE buffer. Use it as XSAVE's instruction mask to select states.
> 
> KVM used to save all xstate via copy_xregs_to_kernel(). Update KVM to set a
> valid fpu->state_mask, which will be necessary to correctly handle dynamic
> state buffers.

All this commit message should say is something along the lines of
"extend copy_xregs_to_kernel() to receive a mask argument of which
states to save, in preparation of dynamic states handling."

> No functional change until the kernel supports dynamic user states.

Same comment as before.

-- 
Regards/Gruss,
    Boris.

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