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 lists1p.gnu.org (lists1p.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 ACB05C61DFD for ; Tue, 1 Sep 2026 02:13:34 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1x1Dze-0001vZ-AW; Mon, 31 Aug 2026 22:12:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1x1Dzb-0001vD-AV for qemu-devel@nongnu.org; Mon, 31 Aug 2026 22:12:56 -0400 Received: from va-2-28.ptr.blmpb.com ([209.127.231.28]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1x1DzX-0007Gh-AP for qemu-devel@nongnu.org; Mon, 31 Aug 2026 22:12:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; s=s1; d=lanxincomputing-com.20200927.dkim.feishu.cn; t=1788228765; h=from:subject:mime-version:from:date:message-id:subject:to:cc: reply-to:content-type:mime-version:in-reply-to:message-id; bh=ltLphJMhYwfdkcEfIotk1IteW6j95X8KR4j7/Rw79+Q=; b=qmXNy+GqxEYMAToZBeqzSTKiNVOKQTGzUa5DVvA3BFuYdmAK1afjaBXnuarSOpvpTUCdVF mlBotmHkK2BGgRASPOQR7HkNMGll/zFOO1pBqDCChHHxoypdmB3PsryAgyPJUY/sg9Slj+ KyeOTLIhj1fpdczsOwuNn41DvqwWG9iZw/0rpGyvDNS7I7THHr2P/tAfD1AATKa8aakR3R IpBNteJPdGEIlHE2xNS11/Yg/55skjnRr23SCbZTSCA1F9S0w8ci6p4/o//GP8/6oj0eGa Ypis4SwXdLaVfhYG9qI4+QtgD0iy9L8uV42G1cKZFdKcv5snrhSKsP9yCD8a6g== X-Original-From: BillXiang User-Agent: Mozilla Thunderbird X-Lms-Return-Path: Content-Transfer-Encoding: quoted-printable In-Reply-To: Cc: =?utf-8?q?Alex_Benn=C3=A9e?= , "Albert Esteve" , "Alberto Faria" , "Alessandro Di Federico" , "Alistair Francis" , "Anton Johansson" , "Markus Armbruster" , "Brian Cain" , "Daniel P. Berrange" , "Chao Peng" , , =?utf-8?q?C=C3=A9dric_Le_Goater?= , , , "Demi Marie Obenour" , , "Eric Blake" , , "Edgar E. Iglesias" , "Eduardo Habkost" , "Elena Ufimtseva" , "Auger Eric" , , , "Alyssa Ross" , , "Warner Losh" , , "Jan Kiszka" , "Jason Gunthorpe" , , "Jim Shu" , "Joao Martins" , "Konrad Rzeszutek Wilk" , "Luc Michel" , "Manos Pitsidianakis" , =?utf-8?q?Marc-Andr=C3=A9_Lureau?= , , "Max Chou" , "Mark Burton" , "Ho, Nelson" , "Paul Walmsley" , "Paolo Bonzini" , "Peter Maydell" , "QEMU Developers" , "Roberto Campesato" , "Richard Henderson" , "Shameerali Kolothum Thodi" , "Bernhard Beschow" , "Stefan Hajnoczi" , "Thomas Huth" , , "Wei Wang" , , "LIU Zhiwei" , Mime-Version: 1.0 Subject: Re: KVM/QEMU community call tomorrow - agenda items? Message-Id: <951ba9d4-e3b4-4205-ac87-a92afe302a6b@lanxincomputing.com> Content-Language: en-US References: <877bl6eoqv.fsf@draig.linaro.org> <413b9ba2-20cf-4af6-9998-be46da277c84@lanxincomputing.com> <48cef34d-18c1-4b8c-a75d-19d1d1321634@oss.qualcomm.com> Content-Type: text/plain; charset=UTF-8 To: "Peter Xu" , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= Date: Tue, 1 Sep 2026 10:12:37 +0800 From: "BillXiang" Received: from [127.0.0.1] ([123.120.5.129]) by smtp.feishu.cn with ESMTPS; Tue, 01 Sep 2026 10:12:41 +0800 Received-SPF: pass client-ip=209.127.231.28; envelope-from=xiangwencheng@lanxincomputing.com; helo=va-2-28.ptr.blmpb.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, MSGID_FROM_MTA_HEADER=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 9/1/2026 1:05 AM, Peter Xu wrote: > On Mon, Aug 31, 2026 at 05:46:12PM +0200, Philippe Mathieu-Daud=C3=A9 wro= te: >> On 31/8/26 13:49, BillXiang wrote: >> >>> How about discussing the patch[1]: >>> "virtio: Add aligned ld/st accessors for vring". >>> >>> As pointed out in the patch, this has been a long-standing issue. It is >>> now necessary to introduce atomic accessors for fields that require >>> atomicity, such as the avail_idx field in virtio. This support is >>> especially crucial for architectures like RISC-V, which do not natively >>> support misaligned memory accesses. >>> >>> I'm particularly eager to receive more suggestions for it. >=20 > I saw the last email was from me.. >=20 > https://lore.kernel.org/qemu-devel/aoxiBB2Wn8NiL5s6@x1.local/ >=20 > I believe that was what PeterM suggested. I think Richard also at least > partly agrees. so I thought we had at least partial consensus on the roug= h > idea, if not exactly how. >=20 > I confess I haven't fully got the latter part of Richard's comment, > regarding the possibility to reuse accel/tcg/ldst_atomicity.c.inc: that > path seems to invole a guest CPU context, where in the case of reading > virtio ring it is from host and it has no guest CPU context. But I think > we can continue the discussion on the list in that thread. >=20 >> >> This is a very technical topic, not sure if the community call will >> be a better place than the mailing list, in particular if no virtio / >> atomic expert developers appears. We'll see :) >=20 > Yes, I had such similar feeling that the problem was not yet blocked by > something that a video call would better help.. >=20 > For example, I still want to double check if that change would work for > your current use case, it will at least verify the thought, no matter if = we > want to use it or not. >=20 > Thanks, >=20 Thanks for your reply. Your change works for the virtio use case. While=20 waiting for further comments, I've also gathered some additional=20 information. Let's continue the discussion on the original thread. -- BillXiang