From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E8D75C282E3 for ; Thu, 25 Apr 2019 12:37:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 81439206BF for ; Thu, 25 Apr 2019 12:37:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727603AbfDYMho (ORCPT ); Thu, 25 Apr 2019 08:37:44 -0400 Received: from foss.arm.com ([217.140.101.70]:42884 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726198AbfDYMho (ORCPT ); Thu, 25 Apr 2019 08:37:44 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C93D015A2; Thu, 25 Apr 2019 05:37:43 -0700 (PDT) Received: from [10.1.196.50] (e108454-lin.cambridge.arm.com [10.1.196.50]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E82EB3F5C1; Thu, 25 Apr 2019 05:37:41 -0700 (PDT) Subject: Re: [PATCH v3 2/3] arch/arm64: fpsimd: Introduce fpsimd_save_and_flush_cpu_state() and use it To: Dave Martin Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, ard.biesheuvel@linaro.org, julien.thierry@arm.com, marc.zyngier@arm.com, catalin.marinas@arm.com, suzuki.poulose@arm.com, will.deacon@arm.com, christoffer.dall@arm.com, james.morse@arm.com References: <20190423135719.11306-1-julien.grall@arm.com> <20190423135719.11306-3-julien.grall@arm.com> <20190424131719.GS3567@e103592.cambridge.arm.com> From: Julien Grall Message-ID: <97a49fad-380b-4494-9722-03857441ffe5@arm.com> Date: Thu, 25 Apr 2019 13:37:40 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190424131719.GS3567@e103592.cambridge.arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dave, On 24/04/2019 14:17, Dave Martin wrote: > On Tue, Apr 23, 2019 at 02:57:18PM +0100, Julien Grall wrote: >> tent-Length: 4295 >> Lines: 128 >> >> The only external user of fpsimd_save() and fpsimd_flush_cpu_state() is >> the KVM FPSIMD code. >> >> A following patch will introduce a mechanism to acquire owernship of the >> FPSIMD/SVE context for performing context management operations. Rather >> than having to export the new helpers to get/put the context, we can just >> introduce a new function to combine fpsimd_save() and >> fpsimd_flush_cpu_state(). >> >> This has also the advantage to remove any external call of fpsimd_save() >> and fpsimd_flush_cpu_state(), so they can be turned static. >> >> Lastly, the new function can also be used in the PM notifier. >> >> Signed-off-by: Julien Grall >> >> --- >> kernel_neon_begin() does not use fpsimd_save_and_flush_cpu_state() >> because the next patch will modify the function to also grab the >> FPSIMD/SVE context. >> >> Changes in v3: >> - Rework the commit message >> - Move the prototype of fpsimd_save_and_flush_cpu_state() >> further down in the header >> - Remove comment in kvm_arch_vcpu_put_fp() >> >> Changes in v2: >> - Patch added >> --- >> arch/arm64/include/asm/fpsimd.h | 5 ++--- >> arch/arm64/kernel/fpsimd.c | 17 +++++++++++++---- >> arch/arm64/kvm/fpsimd.c | 4 +--- >> 3 files changed, 16 insertions(+), 10 deletions(-) >> >> diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h >> index b73d12fcc7f9..c311d36ecffe 100644 >> --- a/arch/arm64/include/asm/fpsimd.h >> +++ b/arch/arm64/include/asm/fpsimd.h >> @@ -48,8 +48,6 @@ struct task_struct; >> extern void fpsimd_save_state(struct user_fpsimd_state *state); >> extern void fpsimd_load_state(struct user_fpsimd_state *state); >> >> -extern void fpsimd_save(void); >> - >> extern void fpsimd_thread_switch(struct task_struct *next); >> extern void fpsimd_flush_thread(void); >> >> @@ -63,7 +61,8 @@ extern void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *state, >> void *sve_state, unsigned int sve_vl); >> >> extern void fpsimd_flush_task_state(struct task_struct *target); >> -extern void fpsimd_flush_cpu_state(void); >> + >> +extern void fpsimd_save_and_flush_cpu_state(void); > > Nit: You could drop this blank line: these are all "state maintenance" > operations, roughly speaking. > > But don't bother unless you respin for some other reason. It looks like I will need to make some changes in patch #3. So I will remove the line at the same time. > > [...] > > With or without that, > > Reviewed-by: Dave Martin Thank you! Cheers, -- Julien Grall