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