Re: [PATCH v4 06/39] x86/fpu: Add helper for modifying xstate

[Borislav Petkov]

On Fri, Dec 02, 2022 at 04:35:33PM -0800, Rick Edgecombe wrote:
> +void fpregs_lock_and_load(void)

Fun naming :)

> +{
> +	/*
> +	 * fpregs_lock() only disables preemption (mostly). So modifing state

Unknown word [modifing] in comment.
Suggestions: ['modifying',...

> +	 * in an interrupt could screw up some in progress fpregs operation,
> +	 * but appear to work. Warn about it.
> +	 */
> +	WARN_ON_ONCE(!irq_fpu_usable());
> +	WARN_ON_ONCE(current->flags & PF_KTHREAD);
> +
> +	fpregs_lock();

So it locks them here...

/me goes further into the patchset

aha, and the counterpart of this function is fpregs_unlock() so
everything gets sandwitched between the two.

Ok, I guess.

> +EXPORT_SYMBOL_GPL(fpregs_lock_and_load);

Exported for KVM?

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette