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 0A37A10775E7 for ; Wed, 18 Mar 2026 16:58:58 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1w2uEF-0002eb-6s; Wed, 18 Mar 2026 12:58:43 -0400 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 1w2uEC-0002cR-Sp for qemu-devel@nongnu.org; Wed, 18 Mar 2026 12:58:40 -0400 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 1w2uEA-0000rx-Rd for qemu-devel@nongnu.org; Wed, 18 Mar 2026 12:58:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1773853118; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MF+W7Q1FPVM8eF/BO26ApBMvg7uNOHbrVev761rVyUM=; b=blRLsBhAJywk+czdIM6dHMSPDRR3scIQl0IVgkdbNRfwro0wXUNkp7KgzB3/aI+CyQAZyx VgUYLMxxD4tBlJ9sAD2fkEbRUbUTD/EL34c4eSEqU9yBBdUC+4GvMnr2q79mK4JjnJidVw /ioyXSEPAmpvLSHD4XfDSsArAylCfVQ= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-203-sEI-Us4cM8mCCX4c1DeQUQ-1; Wed, 18 Mar 2026 12:58:34 -0400 X-MC-Unique: sEI-Us4cM8mCCX4c1DeQUQ-1 X-Mimecast-MFC-AGG-ID: sEI-Us4cM8mCCX4c1DeQUQ_1773853111 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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 mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A8A7B180060D; Wed, 18 Mar 2026 16:58:31 +0000 (UTC) Received: from redhat.com (unknown [10.44.33.194]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EE8F930001A1; Wed, 18 Mar 2026 16:58:28 +0000 (UTC) Date: Wed, 18 Mar 2026 16:58:25 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Pedro Falcato , John Snow , qemu-block@nongnu.org, qemu-devel@nongnu.org, qemu-stable@nongnu.org, Niklas Cassel Subject: Re: [PATCH] ide: Set IDENTIFY word 93 to 0 on SATA drives Message-ID: References: <20260318162951.1060969-1-pfalcato@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -3 X-Spam_score: -0.4 X-Spam_bar: / X-Spam_report: (-0.4 / 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.819, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.903, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, Mar 18, 2026 at 04:54:45PM +0000, Daniel P. Berrangé wrote: > On Wed, Mar 18, 2026 at 04:29:51PM +0000, Pedro Falcato wrote: > > According to the ATA Command Set specification (and the SATA specification > > too), SATA drives are supposed to set word 93 (which for PATA holds hardware > > reset results) to 0. As such, clear it when ncq_queues > 0 (which is only true > > for SATA drives). > > > > Doing so fixes a quirk in Linux where it thinks the AHCI QEMU drive is PATA > > over a SATA bridge, and thus limits maximum transfer sizes for individual IOs > > with a: > > [ 1.632121] ata1.00: applying bridge limits > > > > While at it, bump the device's firmware revision for IDENTIFY. This makes it > > so Linux can avoid enabling a quirk for fixed QEMU releases. > > > > Link: https://lore.kernel.org/linux-ide/20260303183337.1013474-1-pfalcato@suse.de/ > > Cc: qemu-stable@nongnu.org > > Suggsted-by: Niklas Cassel > > Signed-off-by: Pedro Falcato > > --- > > Note: I understand the version bump is vaguely controversial (particularly > > exposing the QEMU version in the string) but I don't have a much better > > idea. Logically, bumping it to 11.0 for stable releases doesn't make much > > sense. > > Bumping the version string changes guest ABI, so such a change should > normally be tied to a new machine type version, not unconditionally > changed. That would also in turn make it unsuitable for QEMU stable > release branches which don't take changes which affect machine type > ABI. > > IMHO Linux should just assume any actively maintained distro that > cares about this problem will fix their QEMU releases and not try > to add a version specific workaround. Having said that, possibly the functional fix itself might need to be tied to the machine type too, given that it is triggering a behavioural change in the emulation and guest driver ? If that's the case, then the version could be changed at the same time. > > > hw/ide/core.c | 12 ++++++++++-- > > 1 file changed, 10 insertions(+), 2 deletions(-) > > > > diff --git a/hw/ide/core.c b/hw/ide/core.c > > index b45abf067b20..89f62f301e94 100644 > > --- a/hw/ide/core.c > > +++ b/hw/ide/core.c > > @@ -211,7 +211,15 @@ static void ide_identify(IDEState *s) > > put_le16(p + 87, (1 << 14) | 0); > > } > > put_le16(p + 88, 0x3f | (1 << 13)); /* udma5 set and supported */ > > - put_le16(p + 93, 1 | (1 << 14) | 0x2000); > > + if (s->ncq_queues) { > > + /* > > + * This is SATA, which is required by the spec to return 0 for this > > + * field. > > + */ > > + put_le16(p + 93, 0); > > + } else { > > + put_le16(p + 93, 1 | (1 << 14) | 0x2000); > > + } > > /* *(p + 100) := nb_sectors -- see ide_identify_size */ > > /* *(p + 101) := nb_sectors >> 16 -- see ide_identify_size */ > > /* *(p + 102) := nb_sectors >> 32 -- see ide_identify_size */ > > @@ -2660,7 +2668,7 @@ int ide_init_drive(IDEState *s, IDEDevice *dev, IDEDriveKind kind, Error **errp) > > if (dev->version) { > > pstrcpy(s->version, sizeof(s->version), dev->version); > > } else { > > - pstrcpy(s->version, sizeof(s->version), qemu_hw_version()); > > + pstrcpy(s->version, sizeof(s->version), "11.0"); > > } > > > > ide_reset(s); > > -- > > 2.53.0 > > > > > > With regards, > Daniel > -- > |: https://berrange.com ~~ https://hachyderm.io/@berrange :| > |: https://libvirt.org ~~ https://entangle-photo.org :| > |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :| > > With regards, Daniel -- |: https://berrange.com ~~ https://hachyderm.io/@berrange :| |: https://libvirt.org ~~ https://entangle-photo.org :| |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :|