From: Andy Lutomirski <luto@kernel.org>
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
Andrew Lutomirski <luto@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Radim Krcmar <rkrcmar@redhat.com>, kvm list <kvm@vger.kernel.org>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
Rik van Riel <riel@surriel.com>
Subject: Re: [PATCH 07/11] x86/pkeys: Drop the preempt-disable section
Date: Fri, 12 Oct 2018 11:07:28 -0700 [thread overview]
Message-ID: <CALCETrVm1ZygpEz+912BcMgTAPznB24uYsB1yQ_V4YQa2N-DzQ@mail.gmail.com> (raw)
In-Reply-To: <1351ba57-1e17-1d76-63c2-0eead2cc5f3b@linux.intel.com>
On Fri, Oct 12, 2018 at 10:58 AM Dave Hansen
<dave.hansen@linux.intel.com> wrote:
>
> On 10/04/2018 07:05 AM, Sebastian Andrzej Siewior wrote:
> > The fpu->initialized flag should not be changed underneath us. This might be a
> > fallout during the removal of the LazyFPU support. The FPU is marked
> > initialized as soon as the state has been set to an initial value. It does not
> > signal if the CPU's FPU registers are loaded.
>
> If this is true, then the check for fpu->initialized should also go away.
>
All these "if" statements in the FPU code are messy and make
understanding and reviewing this code hard.
Can you prepare a patch for the beginning of your series that removes
fpu->initialized and just ensures that the fpu is always initialized?
This will regress performance, but you should get all that performance
back with TIF_LOAD_FPU.
next prev parent reply other threads:[~2018-10-12 18:07 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 [this message]
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
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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