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 smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (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 602B5CD342E for ; Tue, 19 Sep 2023 00:54:16 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id E360282216; Tue, 19 Sep 2023 00:54:15 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp1.osuosl.org E360282216 Authentication-Results: smtp1.osuosl.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=opensynergy.com header.i=@opensynergy.com header.a=rsa-sha256 header.s=TM-DKIM-20210503141657 header.b=02wAPpue X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id gmpETTVMIsWA; Tue, 19 Sep 2023 00:54:15 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp1.osuosl.org (Postfix) with ESMTPS id 5232F82213; Tue, 19 Sep 2023 00:54:14 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp1.osuosl.org 5232F82213 Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 0DB3EC0039; Tue, 19 Sep 2023 00:54:14 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 4427FC0032 for ; Tue, 19 Sep 2023 00:54:12 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 0F440418ED for ; Tue, 19 Sep 2023 00:54:12 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org 0F440418ED Authentication-Results: smtp4.osuosl.org; dkim=pass (2048-bit key) header.d=opensynergy.com header.i=@opensynergy.com header.a=rsa-sha256 header.s=TM-DKIM-20210503141657 header.b=02wAPpue X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Ngekl7h2EHCJ for ; Tue, 19 Sep 2023 00:54:09 +0000 (UTC) X-Greylist: delayed 1093 seconds by postgrey-1.37 at util1.osuosl.org; Tue, 19 Sep 2023 00:54:09 UTC DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org 2951E414E2 Received: from refb02.tmes.trendmicro.eu (refb02.tmes.trendmicro.eu [18.185.115.60]) by smtp4.osuosl.org (Postfix) with ESMTPS id 2951E414E2 for ; Tue, 19 Sep 2023 00:54:09 +0000 (UTC) Received: from 104.47.7.172_.trendmicro.com (unknown [172.21.10.134]) by refb02.tmes.trendmicro.eu (Postfix) with ESMTPS id 2838D108CC445 for ; Tue, 19 Sep 2023 00:35:59 +0000 (UTC) Received: from 104.47.7.172_.trendmicro.com (unknown [172.21.201.37]) by repost01.tmes.trendmicro.eu (Postfix) with SMTP id 0ECD41000008D; Tue, 19 Sep 2023 00:35:53 +0000 (UTC) X-TM-MAIL-RECEIVED-TIME: 1695083752.571000 X-TM-MAIL-UUID: de676031-97e5-4ed5-94ce-a968fe27ed5e Received: from DEU01-BE0-obe.outbound.protection.outlook.com (unknown [104.47.7.172]) by repre01.tmes.trendmicro.eu (Trend Micro Email Security) with ESMTPS id 8BAAD100012A5; Tue, 19 Sep 2023 00:35:52 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=HA/xigINi+e53SX5qmy5QxFNUrasSrqbJLqixQpWPfmnQ+NHqql3hRGtJeIu4C86O74KLWzQLV9M2A8EA3/fGu20CTdxTc6RK51JRkL4vEOupT/aXQJvaCShsOulR6CdvjIljWUOY7n55dFksU7VnJhTtGNpxUfUR4tAGRcgKcolU4kfP1iyRy+8qnGS99zqp7YwoYDitegA4V7OOu4asAEx3xiyry0+tbQbQvB+6i1eHCppdvSzvgqWxCz9YURJ0OKwcEyz6QgALRDUUroXKyUxD3I7YZ5lt2DzUQIHXmpxexWtk08cC0Kayb3ulE3K1CekH/wxQWZgCF3WjdslZw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=0AkVN00jV0ovnSPOUOAH/+DSj+DeSRLRYZQjbtGSxaY=; b=JVC+lTLlVmz9X4TJHdSW5H3iLmeljpT2JzEDeU/WJeImO2DqsVVCiexWxckjBxE/1t+z2NZ2yU0ApRf3gAHqjwPovDO0qFJ/EDuv8K4hmi1IQ3ghS5v2o3xTajxt8BZx1XxQPGUoDNJMPN6vFjCMfpOkBwnIhoyQHmE2EADfEulmcgeIABGyvm9+3QB5z87tf53Pv6WjQirZKBrUsOtC+/uGdE/+ubkNGKIOERR/0np+gIHJ93k3HxW33qkfLd4//OBPXPVakc4KebOcZdhlD/E/eKREOzhfY412sSVqtXHx4ALj1+9opIkHnWaOmfR0NLhYDYEjzpTXJx+hIDwlMQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=opensynergy.com; dmarc=pass action=none header.from=opensynergy.com; dkim=pass header.d=opensynergy.com; arc=none Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=opensynergy.com; Message-ID: Date: Tue, 19 Sep 2023 09:35:36 +0900 Subject: Re: virtio-sound linux driver conformance to spec To: Matias Ezequiel Vara Larsen , virtualization@lists.linux-foundation.org References: Content-Language: en-US In-Reply-To: X-ClientProxiedBy: TYCPR01CA0157.jpnprd01.prod.outlook.com (2603:1096:400:2b1::10) To BEZP281MB2374.DEUP281.PROD.OUTLOOK.COM (2603:10a6:b10:5c::11) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BEZP281MB2374:EE_|FR0P281MB1449:EE_ X-MS-Office365-Filtering-Correlation-Id: 51c2cb59-d5af-45f9-e198-08dbb8a86010 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:BEZP281MB2374.DEUP281.PROD.OUTLOOK.COM; PTR:; CAT:NONE; SFS:(13230031)(396003)(376002)(39840400004)(346002)(366004)(136003)(186009)(1800799009)(451199024)(53546011)(66899024)(83380400001)(86362001)(31696002)(38100700002)(2616005)(36756003)(26005)(41300700001)(316002)(42186006)(66476007)(66556008)(66946007)(2906002)(44832011)(5660300002)(8936002)(4326008)(8676002)(31686004)(478600001); DIR:OUT; SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?NXcxbXBtS2UycExEc3hDRkIxRG5RZkRLalVSbWFuaEI5YnpxMjVvaTV6dE1T?= =?utf-8?B?TlUrU1dPbWJMUmVYNit0ZERkbFVSYWJYU1pXNVlrUlhWc0I2UldrVzBzWENH?= =?utf-8?B?NzhQd0tnVlo5M3JDRG9ZWXE1dDVsNTBPQndrVUR1K3pSNE5DZGNHMmJKdUFp?= =?utf-8?B?Y1NqYzFDQnFReUdWQlpqWXo4M0tRN3lxUnVFZ20zUi9NS0VzL3VKSkkzRDNx?= =?utf-8?B?SHhybCs3WnFXWS9FbEMyYmg1djdBRVhEdS9QdnRCMmQrcHUxNEFFZzN0aTJl?= =?utf-8?B?d1ZuTU5TZnAzN1U0TGlVcEt1Z1RNWUc2MXBlclFsYU5aL1QvTWltK256b3Rk?= =?utf-8?B?cXVQTVpwZnhzSG5YKzFlY0NYRENYYUJ0dW1Kd05qdnlQYW95cGFGVzUzTFlO?= =?utf-8?B?NDFKY3h3MTVZTjFQbkE0WXBleTBmcFFuZkVhelVsaGROaTRxK0wwMHh0QjVw?= =?utf-8?B?dSthekVaS3djZm82OW1HZkFJSlRGa2IvWjdFSFVxMEVxWTFaUVExQ1RDS0xx?= =?utf-8?B?ZUovbjBxWnFMcWsxbS84ZUdwWWFEWjVEV2E3U2srMzB5b1pkczJ3R3dhaXZa?= =?utf-8?B?RitmVlIyZ2k3WkJ6a2lGandNcHZSbFVKa01pUXZpZGNWTFZCeCt5M3ZGNHBW?= =?utf-8?B?Ry8rTzFwTUwrN1pSNDVtTklQY1NCMUlTK013cERUVktMdHRlVlVXRXNTNjhS?= =?utf-8?B?VFNPSkYvRlRDeTVRT3lJQjUrbXZtalJhaWtEVHJGMW5BRitFVlZlVXJEUEdi?= =?utf-8?B?K2VHanhPS0hTWmdjNHM0T3BBcmxHNEVCdzF1VjRJb2l3MUxLR0VBVEtSbWJ0?= =?utf-8?B?aEJqRW9TYWZSdENEQ1h4d0xZZ2Mzcjk5TU1xa1FTS1k2K1pyZUNySm5Ubkpx?= =?utf-8?B?a0tLQVpqTUJja25qcmFwR2tmelR6QUpZT2o2MjIyRFk4Y3B3TDRENi9lTXRC?= =?utf-8?B?R2xNbTZoUHRINi85dWNDZDM2bFp1dUtGbEhLSGJ3ZURnM2NNVmtnUW5vT3Ja?= =?utf-8?B?STRXVnVQQkRrdU9mdWRjazdiTDdRUktUWW9aZTF3SjYxMll1NzkyR1ozNWNW?= =?utf-8?B?VkNhTVEva25Qbm5QR0M0VnBqTjZHbmp0V1dTSzJPYzFSaXlSYU9pMWY2RlAw?= =?utf-8?B?N1RGeDJEWlpBcnVhTS81eVI3K3lyTkpBMHZzaWpOVFgxS1l1UncrK0pLWCtG?= =?utf-8?B?VHFGVDluUWFzeldLaFNnaG5NMXkyN3NiU0h3Tjl6QUs1STk4YUl0c0FEMm0y?= =?utf-8?B?cTB5LzRsMDdVcVNNU1RyU01lb0lBekxwYmpGbGYvUENCOExyUjYvUHlaWG1J?= =?utf-8?B?c1hxWVJoYjRjQVNBUnM0UjNrejg3a0JQbUtDd0dpaWhjeDZkQXkzck9yNjNC?= =?utf-8?B?eVVVVXlXZm9COFZtUndoaE1qVjUxUWFvRnk3bGpML1g5eVgzSUE4ajVyVVBE?= =?utf-8?B?NFdNRk0wKzZMRDM4K1podUJ3SGwzOHMyMHVJNEJ4ckhueFl4REsrRXZRWE1I?= =?utf-8?B?Y0FmeUVZdGU0ZlFRNEJOcHZEUmdwS21GTStlZE8rWTdqeDJEWkd0cWVsY2hu?= =?utf-8?B?L3dVQ3hkUTJhTC9jSW9zbVdVcUQ3T3p3OXg0ZWZJTHo4R3lBWFBIZWptM1Ev?= =?utf-8?B?RGltNlQ4RktqRUhoOFVaZnhBTnQ1d1dZTzQ5T3VwUzhtQWJjbm5uSXh6cWVO?= =?utf-8?B?OXBNR0I4bHhHY1MzUW1rb1FoaWw4WFdzaDRhR1AvTzNjY3BOaEdhZXFPSE12?= =?utf-8?B?cUl5aG9VenRYMFpnOXdNdGZGbmNPSFJSNTVsbGM0S2UxTE90WmFEWjE5TzBH?= =?utf-8?B?TDloYmpYTjkzSXVlamhOWDVJMFBYZ2lCa0NSSldSMW1HZlJPaFVMUFJqSUU3?= =?utf-8?B?NEVYR0lTVkFjVmFHTWtIajVEZkJNN0cwcjFYeEF1eU8wZ0NxS2FwSFdMSGFW?= =?utf-8?B?djFiUGRMYnNiRktiaXRWank1RmUrZXp4Zm1tMlJhMjk2Q1JucmQ3bjZoMXZW?= =?utf-8?B?TjZuUFg4b0FReFlwUGZ3dlU1Y1gvZVRWZHcrazE4VFFZbHUxQWtHRFlORUdr?= =?utf-8?B?dkxCUlNlZXltTGNFQlRLSk5IR2NkakNvVEZXTVpLMXB2alQ1WktBeXZUbHlV?= =?utf-8?Q?ERNg2q0ExfnECZ3EUf2HoOPOr?= X-OriginatorOrg: opensynergy.com X-MS-Exchange-CrossTenant-Network-Message-Id: 51c2cb59-d5af-45f9-e198-08dbb8a86010 X-MS-Exchange-CrossTenant-AuthSource: BEZP281MB2374.DEUP281.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Sep 2023 00:35:51.2278 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 800fae25-9b1b-4edc-993d-c939c4e84a64 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 07g710TJbBLMU0bJTSfdW3ABioefzyqZcOZ1M5Dr7nA8CGJO5WiM7VCyJI1PtZ4pn9nGDawzEIHDOfVzbkAOdQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: FR0P281MB1449 X-TM-AS-ERS: 104.47.7.172-0.0.0.0 X-TMASE-Version: StarCloud-1.3-9.1.1015-27884.003 X-TMASE-Result: 10--13.472100-4.000000 X-TMASE-MatchedRID: 6otD/cJAac1TzAVQ78TKJRhvdi92BBAuMKBMviil9LIrHeGVS/Qy54Jb qOf8l3HTPXE7GzZeNWoQjSTsX7NxDl9un4KO0k1IeJchdZcr1K17tzq0SRd7O+rZB6IUDx4z9qR lMdfby7NPNUC/0aJ9mZX1ZKrmfYbf4sA7mMvlPAbgR8l2Qhmx6u3TwCSAUXKdG6vaCwbpHWQP12 QyCbARkqjkFw2Y4nUlB5MBFiadwD/b1DU5v5X5Bgvpq/ti8dx86wJlKkXfZVlBMJQB/z5Xnkvro ijrBN2VBXbmOqaCMopMiTCzKkc87cddJPEKsqAMES46qCSbf/WZUQpIAWzul9c3FFASMLG5Wjsa YI4lh3U7nRP0DvgcK+Ao/vp8hv08et0MZC9Rv1eh84aqJW318k6UmRuu9LoMyD6UVRc1BSjd0RB dwR2HlA== X-TMASE-XGENCLOUD: 110acd2a-a2d9-4555-b0de-e077779a6ed3-0-0-200-0 X-TM-Deliver-Signature: 56976BC925906F0ACACEAD2348B5D16C X-TM-Addin-Auth: EKG9nSxf6ZZlmMzZHOI2R9stTOTCXGvm2tBsbh4r4BDw1nO4Ahx+bpwExYt 1ABe4G+loDkUKqLpqxW0KW3fjFwH25m0mck/rwobTuzloXRcIdrtlUiSGMw1c0XgAcID9ogZSr7 JzhymUqh3dUvjWC63k3PMPfa6BjpjbsmzC7LgLeKG7j1zoiEw6QPxuJyEBocGme9pNbOYj8+6t3 MXmI5v4QLhy/Pj1aqIl4uV2T1sHLGTu3GNNdICu7kjBlnVESLi2We5dw0KCeez6bQyR4ordrxcj R8B/S06LyKMiSZI=.3dSHq6mJYHfVwDNOuCdjTXwnJ7NsplTMBoMIVsh/DhUuNb+3B7ORhQj2wR euQQ7VYu+MuNk0d77p3EUg0l7YGYa/1rkKXTUHxTpme+l8o+G1tUfr4ZKF8PED9vkY+8afzGSKR 6IE32EZDFMdCCwGc93tXv15J7Ni7TxlOO0hpz6QGVBii5JyQzqvZzablXbIR+GSC0uRvaNfWExp YO3JHpk18RMw+s2xzaGl0VG9lUNeRQ9GOnJZ0xdGiiS+gu09e1JlskuQSyIb5gT/bvSfE4AGaX8 kcZOIczJNr8xMyAr/jxDd427ZmSIUQEbYobQ8rbInpGzD7RojFDkx28h0ag== X-TM-Addin-ProductCode: EMS DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=opensynergy.com; s=TM-DKIM-20210503141657; t=1695083752; bh=JBTjFYljRVi0rkw11RcnvUTjZMnQO8IWeQAXvneJvV0=; l=2021; h=Date:To:From; b=02wAPpue29nXQkpNJlIzJQlMAHDrAq4CLkYaMSUW3OM4ebFB7u31ee90391RrDT6F +UPIaYwTU1IYbGk1HG+5itNeF5Q+bHTTTvsTod7S12SXjaYhRoQrtotaedpXmrDJpU NuCQGO9bhKzfNzNIlM5FglEyGsYl4mYNmDR9NFc561b7u1Mu/5SeRsCtdd5s0tlSQw 4YRlMVLPqxhIO0TdOjINvFhFqO2EQkA+7Rwlhy2HaZ7ROJnIQwiPfGKpfJO73FB1nh Len+S14v5MNY8Lv0iliaSlOaLiT8xZfhqHaxcPTjosuJR4pXIuk99gg/0h0J6t96Ld mBTGrKdtoVEeQ== Cc: mst@redhat.com, stefanha@redhat.com, virtio-comment@lists.oasis-open.org X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Anton Yakovlev via Virtualization Reply-To: Anton Yakovlev Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" Hello Matias, On 14.09.2023 00:04, Matias Ezequiel Vara Larsen wrote: > Hello, > > This email is to report a behavior of the Linux virtio-sound driver that > looks like it is not conforming to the VirtIO specification. The kernel > driver is moving buffers from the used ring to the available ring > without knowing if the content has been updated from the user. If the > device picks up buffers from the available ring just after it is > notified, it happens that the content is old. This problem can be fixed > by waiting a period of time after the device dequeues a buffer from the > available ring. The driver should not be allowed to change the content > of a buffer in the available ring. When buffers are enqueued in the > available ring, the device can consume them immediately. > > 1. Is the actual driver implementation following the spec? If the Linux virtio sound driver violates a specification, then there must be a conformance statement that the driver does not follow. As far as I know, there is no such thing at the moment. During the design discussion, it was decided that the driver should implement typical cyclic DMA logic. And the main idea behind was that, unlike many other virtio devices, the sound device is isochronous. It consumes or supplies data at a fixed rate. Which means that the device (in an idealized case) should access buffers in virtqueues not as soon as they are available, but when required. Whether this is a good idea or not is a debatable question. > 2. Shall the spec be extended to support such a use-case? There are some things you can try without having to change the spec. The driver now handles RW and MMAP substream access modes in the same way. Someone could try to change the handling of RW mode exactly as you describe, because the UAPI allows it. But this logic cannot be reliably applied to MMAP mode. Best regards, -- Anton Yakovlev Senior Software Engineer OpenSynergy GmbH Rotherstr. 20, 10245 Berlin _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization