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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Borislav Petkov <bp@alien8.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	"H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Tony Luck <tony.luck@intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Rik van Riel <riel@surriel.com>,
	"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
	Fenghua Yu <fenghua.yu@intel.com>,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v2 8/8] x86/fpu/xstate: Restore supervisor xstates for __fpu__restore_sig()
Date: Fri, 28 Feb 2020 13:51:52 +0100	[thread overview]
Message-ID: <20200228125152.nxp6vntmxconc4bj@linutronix.de> (raw)
In-Reply-To: <20200228121724.GA25261@zn.tnic>

On 2020-02-28 13:17:24 [+0100], Borislav Petkov wrote:
> On Thu, Feb 27, 2020 at 02:52:12PM -0800, Yu-cheng Yu wrote:
> > If TIF_NEED_FPU_LOAD is set, then xstates are already in the xsave buffer. 
> > We can skip saving them again.
> 
> Ok, then pls use test_and_set_thread_flag().

I've been told not to do this while I crafted kernel_fpu_begin() because
this would introduce an atomic operation which we want avoid.

Sebastian

  reply	other threads:[~2020-02-28 12:52 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-21 20:18 [PATCH v2 0/8] Support XSAVES supervisor states Yu-cheng Yu
2020-01-21 20:18 ` [PATCH v2 1/8] x86/fpu/xstate: Define new macros for supervisor and user xstates Yu-cheng Yu
2020-02-20 11:47   ` Borislav Petkov
2020-02-20 20:23     ` Yu-cheng Yu
2020-01-21 20:18 ` [PATCH v2 2/8] x86/fpu/xstate: Separate user and supervisor xfeatures mask Yu-cheng Yu
2020-02-21 10:34   ` Borislav Petkov
2020-01-21 20:18 ` [PATCH v2 3/8] x86/fpu/xstate: Introduce XSAVES supervisor states Yu-cheng Yu
2020-01-21 20:18 ` [PATCH v2 4/8] x86/fpu/xstate: Define new functions for clearing fpregs and xstates Yu-cheng Yu
2020-02-21 14:04   ` Borislav Petkov
2020-01-21 20:18 ` [PATCH v2 5/8] x86/fpu/xstate: Rename validate_xstate_header() to validate_xstate_header_from_user() Yu-cheng Yu
2020-02-21 14:13   ` Borislav Petkov
2020-01-21 20:18 ` [PATCH v2 6/8] x86/fpu/xstate: Update sanitize_restored_xstate() for supervisor xstates Yu-cheng Yu
2020-02-21 14:30   ` Borislav Petkov
2020-01-21 20:18 ` [PATCH v2 7/8] x86/fpu/xstate: Update copy_kernel_to_xregs_err() for XSAVES supervisor states Yu-cheng Yu
2020-01-21 20:18 ` [PATCH v2 8/8] x86/fpu/xstate: Restore supervisor xstates for __fpu__restore_sig() Yu-cheng Yu
2020-02-21 17:58   ` Borislav Petkov
2020-02-27 22:52     ` Yu-cheng Yu
2020-02-28 12:17       ` Borislav Petkov
2020-02-28 12:51         ` Sebastian Andrzej Siewior [this message]
2020-02-28 15:53         ` Yu-cheng Yu
2020-02-28 16:23           ` Borislav Petkov
2020-02-28 16:20             ` Yu-cheng Yu
2020-02-28 16:50               ` Sebastian Andrzej Siewior
2020-02-28 16:54                 ` Yu-cheng Yu
2020-02-28 17:22               ` Borislav Petkov
2020-02-28 18:11                 ` Yu-cheng Yu
2020-02-28 18:31                   ` Borislav Petkov
2020-02-28 21:22                     ` Yu-cheng Yu
2020-02-28 21:47                       ` Borislav Petkov
2020-02-28 22:13                         ` Yu-cheng Yu
2020-02-29 14:36                           ` Borislav Petkov
2020-03-02 18:09                             ` Yu-cheng Yu
2020-03-04 18:18                               ` Yu-cheng Yu
2020-03-06 20:50                                 ` Borislav Petkov
2020-03-10 20:36                                   ` Yu-cheng Yu
2020-03-10 21:16                                     ` Thomas Gleixner

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