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 Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by smtp.lore.kernel.org (Postfix) with ESMTP id B7529C433EF for ; Tue, 22 Feb 2022 12:53:25 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 118844B0B4; Tue, 22 Feb 2022 07:53:25 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Zf1tHuiteA93; Tue, 22 Feb 2022 07:53:23 -0500 (EST) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 187FD4B0BA; Tue, 22 Feb 2022 07:53:23 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 840114B0AC for ; Tue, 22 Feb 2022 07:53:22 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Zj1zcGAWwebi for ; Tue, 22 Feb 2022 07:53:21 -0500 (EST) Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 5A67D49EF2 for ; Tue, 22 Feb 2022 07:53:21 -0500 (EST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 85968B819B6; Tue, 22 Feb 2022 12:53:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 248D4C340E8; Tue, 22 Feb 2022 12:53:14 +0000 (UTC) Date: Tue, 22 Feb 2022 12:53:11 +0000 From: Catalin Marinas To: Mark Brown Subject: Re: [PATCH v11 16/40] arm64/sme: Implement streaming SVE context switching Message-ID: References: <20220207152109.197566-1-broonie@kernel.org> <20220207152109.197566-17-broonie@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220207152109.197566-17-broonie@kernel.org> Cc: Basant Kumar Dwivedi , Will Deacon , Luis Machado , Szabolcs Nagy , Marc Zyngier , Shuah Khan , linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org, Alan Hayward , Shuah Khan , kvmarm@lists.cs.columbia.edu, Salil Akerkar X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Mon, Feb 07, 2022 at 03:20:45PM +0000, Mark Brown wrote: > When in streaming mode we need to save and restore the streaming mode > SVE register state rather than the regular SVE register state. This uses > the streaming mode vector length and omits FFR but is otherwise identical, > if TIF_SVE is enabled when we are in streaming mode then streaming mode > takes precedence. > > This does not handle use of streaming SVE state with KVM, ptrace or > signals. This will be updated in further patches. I think I get this but a state diagram somewhere would help ;). IIUC you don't disable SM on a context switch, you just leave it in place until a task_fpsimd_load(). It shouldn't be a problem as kernel_neon_begin() disables it anyway. Reviewed-by: Catalin Marinas _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm