From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Borislav Petkov <bp@alien8.de>
Cc: "Dave Hansen" <dave.hansen@linux.intel.com>,
"Rik van Riel" <riel@surriel.com>,
linux-kernel@vger.kernel.org, x86@kernel.org,
"Andy Lutomirski" <luto@kernel.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
kvm@vger.kernel.org, "Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: Re: [PATCH 10/11] x86/fpu: prepare copy_fpstate_to_sigframe for TIF_LOAD_FPU
Date: Fri, 2 Nov 2018 16:44:16 +0100 [thread overview]
Message-ID: <20181102154416.bgtueiy65o6d23ni@linutronix.de> (raw)
In-Reply-To: <20181015152431.GD11434@zn.tnic>
On 2018-10-15 17:24:31 [+0200], Borislav Petkov wrote:
> On Fri, Oct 12, 2018 at 12:40:19PM -0700, Dave Hansen wrote:
> > > + __fpregs_changes_end();
> >
> > Do we really need the __fpregs_changes_*() abstraction for this single
> > call site?
>
> Yap, I'm staring at those in patch 2, there's no documentation there what
> they're supposed to do, only the commit message of patch 11 says:
>
> "The __fpregs_changes_{begin|end}() section ensures that the register
> remain unchanged. Otherwise a context switch or a BH could save the
> registers to its FPU context and processor's FPU register would remain
> random."
>
> So I'd say we should drop that abstraction, use preempt_* and put that
> text above the single usage site.
There are more than one caller and this function disables preemption and
BH in the end. Therefore I would like to keep it. But as suggested in
the previous patch I will think about renaming it.
> Thx.
Sebastian
next prev parent reply other threads:[~2018-11-02 15:44 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-04 14:05 [PATCH 00/11 v3] x86: load FPU registers on return to userland Sebastian Andrzej Siewior
2018-10-04 14:05 ` [PATCH 01/11] x86/entry: remove _TIF_ALLWORK_MASK Sebastian Andrzej Siewior
2018-10-11 16:27 ` Borislav Petkov
2018-10-04 14:05 ` [PATCH 02/11] x86/fpu: add (__)make_fpregs_active helpers Sebastian Andrzej Siewior
2018-10-04 14:05 ` [PATCH 03/11] x86/fpu: make __raw_xsave_addr() use feature number instead of mask Sebastian Andrzej Siewior
2018-10-11 17:30 ` Christophe de Dinechin
2018-10-18 11:19 ` Sebastian Andrzej Siewior
2018-10-12 15:52 ` Dave Hansen
2018-10-18 11:17 ` Sebastian Andrzej Siewior
2018-10-18 11:21 ` Sebastian Andrzej Siewior
2018-10-17 10:01 ` Borislav Petkov
2018-10-18 11:48 ` Sebastian Andrzej Siewior
2018-10-04 14:05 ` [PATCH 04/11] x86/fpu: eager switch PKRU state Sebastian Andrzej Siewior
2018-10-12 17:51 ` Dave Hansen
2018-10-12 18:09 ` Andy Lutomirski
2018-10-12 19:44 ` Dave Hansen
2018-10-18 16:13 ` Sebastian Andrzej Siewior
2018-10-18 17:50 ` Dave Hansen
2018-10-04 14:05 ` [PATCH 05/11] x86/fpu: set PKRU state for kernel threads Sebastian Andrzej Siewior
2018-10-12 17:54 ` Dave Hansen
2018-10-12 18:02 ` Andy Lutomirski
2018-10-18 16:26 ` Sebastian Andrzej Siewior
2018-10-18 16:48 ` Andy Lutomirski
2018-10-18 17:47 ` Dave Hansen
2018-10-18 18:25 ` Sebastian Andrzej Siewior
2018-10-18 20:46 ` Andy Lutomirski
2018-10-18 20:56 ` Dave Hansen
2018-10-18 21:24 ` Sebastian Andrzej Siewior
2018-10-18 21:58 ` Andy Lutomirski
2018-10-19 7:44 ` Paolo Bonzini
2018-10-19 16:59 ` Andy Lutomirski
2018-10-19 17:01 ` Dave Hansen
2018-10-19 17:37 ` Andy Lutomirski
2018-10-19 18:26 ` Dave Hansen
2018-10-04 14:05 ` [PATCH 06/11] x86/pkeys: make init_pkru_value static Sebastian Andrzej Siewior
2018-10-12 17:55 ` Dave Hansen
2018-10-04 14:05 ` [PATCH 07/11] x86/pkeys: Drop the preempt-disable section Sebastian Andrzej Siewior
2018-10-12 17:58 ` Dave Hansen
2018-10-12 18:07 ` Andy Lutomirski
2018-10-12 20:26 ` Sebastian Andrzej Siewior
2018-10-04 14:05 ` [PATCH 08/11] x86/fpu: Always store the registers in copy_fpstate_to_sigframe() Sebastian Andrzej Siewior
2018-10-11 17:50 ` Christophe de Dinechin
2018-10-11 21:18 ` Andy Lutomirski
2018-10-12 18:15 ` Dave Hansen
2018-11-02 14:42 ` Sebastian Andrzej Siewior
2018-10-04 14:05 ` [PATCH 09/11] x86/entry: add TIF_LOAD_FPU Sebastian Andrzej Siewior
2018-10-04 14:05 ` [PATCH 10/11] x86/fpu: prepare copy_fpstate_to_sigframe for TIF_LOAD_FPU Sebastian Andrzej Siewior
2018-10-12 19:40 ` Dave Hansen
2018-10-15 15:24 ` Borislav Petkov
2018-11-02 15:44 ` Sebastian Andrzej Siewior [this message]
2018-11-02 22:55 ` Sebastian Andrzej Siewior
2018-10-04 14:05 ` [PATCH 11/11] x86/fpu: defer FPU state load until return to userspace Sebastian Andrzej Siewior
2018-10-04 16:14 ` Andy Lutomirski
2018-10-12 20:25 ` Sebastian Andrzej Siewior
2018-10-04 16:45 ` [PATCH 00/11 v3] x86: load FPU registers on return to userland Rik van Riel
2018-10-04 16:50 ` Andy Lutomirski
2018-10-05 11:55 ` Sebastian Andrzej Siewior
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