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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 88C95C4332F for ; Fri, 10 Nov 2023 09:52:14 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1r1OAm-0001vF-9X; Fri, 10 Nov 2023 04:51:32 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r1OAk-0001ug-6t for qemu-devel@nongnu.org; Fri, 10 Nov 2023 04:51:30 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r1OAi-0000uy-3T for qemu-devel@nongnu.org; Fri, 10 Nov 2023 04:51:29 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1699609887; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=cXJ1RxYQQ3fblx2UQui0iEWqJK8BE7cvJy7doe4Q3f0=; b=WFd0ETxb3Td8euQsrikLmgYrH+KladBFmObUUnkx8IBpmSxftDzc7vcir67mCn3liAsFji 1ERXKSMefgteCaAYddzoPcOjnl9Psrq3dcX+XQU2QFl77MedyTkh3u/Vl0r0VxRA1vTTQU Epp2CUnGOaAv58hYgNnIeJf3otZMuok= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-591-z2-irTP_N1KLa6V_OHcsCg-1; Fri, 10 Nov 2023 04:51:22 -0500 X-MC-Unique: z2-irTP_N1KLa6V_OHcsCg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1714A28237C0; Fri, 10 Nov 2023 09:51:22 +0000 (UTC) Received: from redhat.com (unknown [10.39.193.225]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4D8E82026D68; Fri, 10 Nov 2023 09:51:19 +0000 (UTC) Date: Fri, 10 Nov 2023 10:51:18 +0100 From: Kevin Wolf To: Niklas Cassel Cc: John Snow , qemu-block@nongnu.org, qemu-devel@nongnu.org, Damien Le Moal , Marcin Juszkiewicz , Michael Tokarev , Niklas Cassel Subject: Re: [PATCH v3] hw/ide/ahci: fix legacy software reset Message-ID: References: <20231108222657.117984-1-nks@flawful.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231108222657.117984-1-nks@flawful.org> X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Am 08.11.2023 um 23:26 hat Niklas Cassel geschrieben: > From: Niklas Cassel > > Legacy software contains a standard mechanism for generating a reset to a > Serial ATA device - setting the SRST (software reset) bit in the Device > Control register. > > Serial ATA has a more robust mechanism called COMRESET, also referred to > as port reset. A port reset is the preferred mechanism for error > recovery and should be used in place of software reset. > > Commit e2a5d9b3d9c3 ("hw/ide/ahci: simplify and document PxCI handling") > improved the handling of PxCI, such that PxCI gets cleared after handling > a non-NCQ, or NCQ command (instead of incorrectly clearing PxCI after > receiving anything - even a FIS that failed to parse, which should NOT > clear PxCI, so that you can see which command slot that caused an error). > > However, simply clearing PxCI after a non-NCQ, or NCQ command, is not > enough, we also need to clear PxCI when receiving a SRST in the Device > Control register. > > A legacy software reset is performed by the host sending two H2D FISes, > the first H2D FIS asserts SRST, and the second H2D FIS deasserts SRST. > > The first H2D FIS will not get a D2H reply, and requires the FIS to have > the C bit set to one, such that the HBA itself will clear the bit in PxCI. > > The second H2D FIS will get a D2H reply once the diagnostic is completed. > The clearing of the bit in PxCI for this command should ideally be done > in ahci_init_d2h() (if it was a legacy software reset that caused the > reset (a COMRESET does not use a command slot)). However, since the reset > value for PxCI is 0, modify ahci_reset_port() to actually clear PxCI to 0, > that way we can avoid complex logic in ahci_init_d2h(). > > This fixes an issue for FreeBSD where the device would fail to reset. > The problem was not noticed in Linux, because Linux uses a COMRESET > instead of a legacy software reset by default. > > Fixes: e2a5d9b3d9c3 ("hw/ide/ahci: simplify and document PxCI handling") > Reported-by: Marcin Juszkiewicz > Signed-off-by: Niklas Cassel Thanks, applied to the block branch. Kevin