linux-kernel - Re: [PATCH 01/17] x86, fpu: wrap get_xsave

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Message-ID: <20150325141557.GA21694@redhat.com>
Date:	Wed, 25 Mar 2015 15:15:57 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Borislav Petkov <bp@...en8.de>
Cc:	Rik van Riel <riel@...hat.com>,
	Andy Lutomirski <luto@...capital.net>,
	Dave Hansen <dave.hansen@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	X86 ML <x86@...nel.org>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Suresh Siddha <sbsiddha@...il.com>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, Fenghua Yu <fenghua.yu@...el.com>
Subject: Re: [PATCH 01/17] x86, fpu: wrap get_xsave_addr() to make it safer

On 03/25, Borislav Petkov wrote:
>
> On Tue, Mar 24, 2015 at 09:01:44PM -0400, Rik van Riel wrote:
> > Indeed, __save_init_fpu (yeah, terrible name) will save
> > the in-register state to memory for you, so you can
> > inspect it.
> >
> > Is there any reason not to rename __save_init_fpu to
> > save_fpu_state, or just save_fpu?
>
> That whole place there needs more rubbing.
>
> So the way I see it, the "init" thing also says that the FPU is intact.

Yes, this is my understanding too.

And note that nobody actually wants this "init" part, so it actually
means "destroy".

I agree we should rename it later (at least). Plus unlazy_fpu() looks
confusing too. Nobody actually wants to "unlazy", the callers want to
save FPU state. So it could be named save_fpu_state() too ;)

Oleg.

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