From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: passt.top; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=WUAVDBQM; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by passt.top (Postfix) with ESMTPS id 715E25A0262 for ; Wed, 20 May 2026 17:34:53 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1779291292; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3SNq7B3wgf/ZJcf94uFQAbb0HDUMWvNdJXhYBWVYmIs=; b=WUAVDBQM0QZOJKo2pAmsoO7umixGz8A5jtk1ifdDxxyO7LUEFYaaqcYUjKDwjZ0KMQX2NC bm5thRxos5Q+YNQMpTZbnrkLIuKosJWHNOZmeuoEVM5fqIhZLi0jkdZ8etn8JkvqmG4Cpg byASS01EjRcmQlmoukORzeBXN9/fj5c= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-684-Z5zJ2S96PzuAr11M49myhQ-1; Wed, 20 May 2026 11:34:49 -0400 X-MC-Unique: Z5zJ2S96PzuAr11M49myhQ-1 X-Mimecast-MFC-AGG-ID: Z5zJ2S96PzuAr11M49myhQ_1779291288 Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-48e89faa62eso30750505e9.1 for ; Wed, 20 May 2026 08:34:49 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779291288; x=1779896088; h=date:content-transfer-encoding:mime-version:organization:references :in-reply-to:message-id:subject:cc:to:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=3SNq7B3wgf/ZJcf94uFQAbb0HDUMWvNdJXhYBWVYmIs=; b=nXZpWdd7mLlPliFnFtRtEKLXoPL1yLt5JwJLYRu2koJIRDAPHFiZ450MSkgdMuvPZ/ GRlF8hjGW6hx4k0kcykZbet80cv9MgSp2aOifMqGo98OZRih56c50NAje5bzhJH9qDVB PG/UXkcPVUx47TGRQQpHDZ85MQBdrzxyNjUCcu7gcrKY5WGICU8MfufHTLFgya5YUQ0e s8H1OhWcEY7BjAD+aMWs1Qg1TpX+AqtxxqcwgfbWkR5U5aznOucYKsx7AyFl5r7mtYvY oY2r1HeZo3PQ5H9lO52jx483oZSxNsjs51N1Vk+rPbHfRNBA3VlzERtGJXB2o8RVsw34 TVHQ== X-Gm-Message-State: AOJu0YzaEocClfEu2Rc+ZbKsOhJmF1QbOMTff0xvLPdRvvH8T2dfndm9 A9lfbC8mD7angQG5qgq2hTd5VlcPPBE2kPvOx7TzW9XopCuClZGUeYXkAapj+FaukK5IpSTjxnU PQCbq4jedDIYd/r0vrza1ppW/e84gJNnC4G3KRbuzVXkmZTL3VvmjWQ== X-Gm-Gg: Acq92OGOGVrvUDUGAr68Y3pXOHQ4+qo5nJX8cc37eikOtEFuZ9KMP/uZydxLAUwuOAu 6JxDrcFV0tsi0V0eiHV/rW7fblcl6DrCWbeGkq3TcioWijPDiyxj2D+BkAXbMMXWJBXiuXXQnsk N/Mcv68Oa53hbA8X5NQB6kTmm8Fyf3gGVj1poPu9b+K5iFxZvy6sPviot+wyFhNhSGhNI0CnP8V Gg96PAKEc136t32knZzZEPrNg4ajLUfWvToDzF9FAcC+OIoI+C9FAl1ztTAhCf/O1pMTRYTmHnJ XomlwLomm0jbRrFyICSx5t9D9V3ntD91A/cxIZkvWPH57ZiG4rf15lOSaErUuS9Sna55c5meOJH tJbQkpNTeeRpvvewRWemG/MbcEp5YnD3HioKNa9JUp9A= X-Received: by 2002:a05:600c:8189:b0:488:ac01:72b6 with SMTP id 5b1f17b1804b1-48fe6323addmr354648535e9.21.1779291287862; Wed, 20 May 2026 08:34:47 -0700 (PDT) X-Received: by 2002:a05:600c:8189:b0:488:ac01:72b6 with SMTP id 5b1f17b1804b1-48fe6323addmr354648135e9.21.1779291287330; Wed, 20 May 2026 08:34:47 -0700 (PDT) Received: from maya.myfinge.rs (ifcgrfdd.trafficplex.cloud. [2a10:fc81:a806:d6a9::1]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48febe6b60csm200307725e9.6.2026.05.20.08.34.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 May 2026 08:34:46 -0700 (PDT) From: Stefano Brivio To: Laurent Vivier Subject: Re: [PATCH v4 00/10] vhost-user: Preparatory series for multiple iovec entries per virtqueue element Message-ID: <20260520173445.0658dfef@elisabeth> In-Reply-To: <20260513115218.1662850-1-lvivier@redhat.com> References: <20260513115218.1662850-1-lvivier@redhat.com> Organization: Red Hat X-Mailer: Claws Mail 4.2.0 (GTK 3.24.49; x86_64-pc-linux-gnu) MIME-Version: 1.0 Date: Wed, 20 May 2026 17:34:46 +0200 (CEST) X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: tJnIU9FwEw2f6ToxtmYcYaHK4ZOfH5NFgVGPUyppJVE_1779291288 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Message-ID-Hash: ZKXLJIUFJ7ZUCKH6TCVB4H7JL3RQ6QHT X-Message-ID-Hash: ZKXLJIUFJ7ZUCKH6TCVB4H7JL3RQ6QHT X-MailFrom: sbrivio@redhat.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: passt-dev@passt.top, Jon Maloy , David GIbson X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On Wed, 13 May 2026 13:52:08 +0200 Laurent Vivier wrote: > Currently, the vhost-user path assumes each virtqueue element contains > exactly one iovec entry covering the entire frame. This assumption > breaks as some virtio-net drivers (notably iPXE) provide descriptors where the > vnet header and the frame payload are in separate buffers, resulting in > two iovec entries per virtqueue element. > > This series refactors the vhost-user data path so that frame lengths, > header sizes, and padding are tracked and passed explicitly rather than > being derived from iovec sizes. This decoupling is a prerequisite for > correctly handling padding of multi-buffer frames. Sorry to bring (likely) bad news, but this series seems to introduce a regression: I got the migration/rampstream_in tests fail twice in a row, which I've never saw happening (I think I saw a single failure a long time ago when the machine had a high CPU load, but nothing else). I'm currently bisecting and the bisect seems to point towards the end of the series (probably 10/10), but I haven't finished yet. I'll keep you posted. I haven't spotted anything that might cause issues there. It's probably worth mentioning that after migration we send pretty small TCP frames (window probes), but I have no idea yet if that has anything to do. -- Stefano