From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4A59628851F for ; Wed, 8 Jul 2026 15:44:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783525451; cv=pass; b=FaKFqzYr+Vg152TwLYjhM4Z+9xHsMiioE6PLQuoq7D9Sbrt3dc1Q8YaYwFyAeUOzfbr4aK7b+5agUpC5s2V9+orJzThhF0EdL9RbQBhUykBZg8EHtXMuEaqNFhb7AQKIYNWCeLmMLnZnsR6Oy9xY+kbGEHUnEEx4vzeNU0fN9XA= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783525451; c=relaxed/simple; bh=mt9nAcuwW9+WLnizslvOIYfZewCZGL5MdCLQM2Kcr7Y=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=h2EFzsczys0r3jOeEAtd24/GGlgx2teni0USr5EgldJ8i7MiJQlY9mYdsn2owPeZUMED9/P6x+ktjP+FlmJHFv1B2YMa9Z1EDnU93HzuRXRX26+6oI5vuPi9Qv5jMcM1oK0ZJh13aihQt6T2CgGkbvktvQBErTnYic1oeXGvGcw= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=michael.riesch@collabora.com header.b=ijLe/chP; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=michael.riesch@collabora.com header.b="ijLe/chP" ARC-Seal: i=1; a=rsa-sha256; t=1783525443; cv=none; d=zohomail.com; s=zohoarc; b=aMA8SHMTJfbrnVqCwKVy7g6uruDXt+h7dE5fY3dW6zy2QuJmiGEESmw/MnLzQ6eWOH1P/rrapeg54tW0wIrlYl8AE/VjGBs8hadwZJwQXYI0AXqMlGZValljENsWWg3QsH38u63kfirHkJyMhI2cIdkH8CBGkURDAkx2osHVbhw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1783525443; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=LwvAKpUhXjG8M+7dLisvC2lNswzeA9Pmm16wFmiXqYc=; b=MTXMHWBjDwUU9PBBfsgAfXGEqtg+fnfvg9Lr7NitFt/zf2MDUb1LZpfzoM/KM1l4fJkHyOs0oOroUqbfPBBYRLHkonpnS8MHGk7v45uWPomnxWNzt+Tmu4pt6YGlT7kjR+TqoByEyiLwzOCBIrX0C5JdhsOqfNj+rL1xCs+y9/Y= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=michael.riesch@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1783525443; s=zohomail; d=collabora.com; i=michael.riesch@collabora.com; h=Message-ID:Date:Date:MIME-Version:Subject:Subject:To:To:Cc:Cc:References:From:From:In-Reply-To:Content-Type:Content-Transfer-Encoding:Message-Id:Reply-To; bh=LwvAKpUhXjG8M+7dLisvC2lNswzeA9Pmm16wFmiXqYc=; b=ijLe/chPv35nwzXjV1cPAZ5en1avL9jWR4Pw5ah0VN24S64Une5CDH/uknxAaczd 7xXGfGAl0gPuorOWlfJbLp969jkQD25pq43FgdyvWiXUl21n97xJbMIH+UjA/DQnF+/ t6RBsSKM1FcPCMAzF420JF3uf/hR6CNKm/BzfN6c= Received: by mx.zohomail.com with SMTPS id 1783525442033906.0885531555291; Wed, 8 Jul 2026 08:44:02 -0700 (PDT) Message-ID: <45ec0e68-dd5d-4a13-a136-e6cd01df6a26@collabora.com> Date: Wed, 8 Jul 2026 17:43:57 +0200 Precedence: bulk X-Mailing-List: virtio-comment@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 3/6] virtio-msg: Add virtio-msg, a message based virtio transport layer To: Bertrand Marquis , virtio-comment@lists.linux.dev Cc: "Edgar E . Iglesias" , Arnaud Pouliquen , Viresh Kumar , Alex Bennee , Armelle Laine , Bill Mills References: Content-Language: en-US From: Michael Riesch In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ZohoMailClient: External Hi all, Sorry for being late to the party. In January 2026 I received a very warm welcome in the virtio-msg group meetings, which I subsequently attended (or at least, I tried to do so). Now, in July 2026, I finally get around to read the whole thing. The reason for this may have been that "Things just worked (tm)". Basing on Viresh's patches for virtio-msg in the Linux kernel and Mani's work towards virtio-msg over PCIe (including glue code that ties virtio-msg to the PCIe endpoint controller framework), we were able to build a virtual GPU out of a off-the-shelf SBC. So no real reason for intervention, right?! That said, obviously we would like this to happen, and maybe saying out loud that this is superb work and a highly valuable contribution to the ecosystem helps. On 6/15/26 11:10, Bertrand Marquis wrote: > Add a new transport layer that is based on messages. > > This transport layer still uses virtqueues as the other transport layers do > but implements transport layer operations by sending and receiving messages > instead of the "MMR" reads and writes used in virtio-mmio and virtio-pci. > > This transport is useful when the device and driver are both implemented in > software but the trap and emulate operations of virtio-mmio and virtio-pci > can not be used. > > This transport is intended to be used in many situations, including: > * between a host processor and its co-processors > * between two different systems (not SMP) connected via PCIe > * between normal and secure worlds > * host to vm > * vm to vm > > Signed-off-by: Bertrand Marquis > Signed-off-by: Bill Mills > Signed-off-by: Edgar E. Iglesias > Signed-off-by: Arnaud Pouliquen This is superb work and a highly valuable contribution to the ecosystem. Thanks a lot to all people involved in this! Reviewed-by: Michael Riesch One thing, though: > [...] > +\subsubsection{Transport Feature Bits} > +\label{sec:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Transport Feature Bits} > + > +Transport feature bits are bus-instance parameters. They are advertised as part > +of the transport parameters described in > +\ref{sec:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Revisions} > +and are not carried in the device feature blocks exchanged by > +\msgref{GET_DEVICE_FEATURES} and \msgref{SET_DRIVER_FEATURES}. > + > +The following transport feature bits are defined: > + > +\begin{tabular}{|l|l|l|p{7cm}|} > +\hline > +Bit & Name & Minimum revision & Meaning \\ > +\hline > +0 & \texttt{VIRTIO\_MSG\_F\_STRICT\_CONFIG\_GENERATION} & 1 & > +Select strict configuration semantics profile. When this feature is not > +advertised for the bus instance, the baseline profile applies. See > +\ref{sec:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Configuration Semantics Profiles}. \\ > +\hline > +\end{tabular} This table overruns the page width in my LaTeX build?! > [...] Best regards, Michael