From patchwork Mon Feb 17 16:40:12 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Albert Esteve X-Patchwork-Id: 13978292 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 5BE8DC021AA for ; Mon, 17 Feb 2025 16:43:23 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tk4CN-0004ed-Ip; Mon, 17 Feb 2025 11:42:23 -0500 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 1tk4CI-0004cB-VW for qemu-devel@nongnu.org; Mon, 17 Feb 2025 11:42:18 -0500 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 1tk4CG-0007z9-3r for qemu-devel@nongnu.org; Mon, 17 Feb 2025 11:42:18 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1739810535; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rrOHEASD5ETftMjnPAsJydFA8UyEJ3azffjK7xeCoRc=; b=CH2Z1DMfPwMUgMpbnoUTHU0NjABD2fOR6NnI7fZfqRqv7jD1xqrUgZbmlBUZ/5YxyNFFDF k/TuogsPG97Nv1UFLgYYDe1DeEENkzByRgHnAko+5pkwVOyITpZl+tsiMS5OC7YDjdUzBM DfkZnsF9JQXXYuJne6FR2fZ7QVIA09M= Received: from mx-prod-mc-08.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-679-Ghl4AiDdM6Wz8Gl_v4r54Q-1; Mon, 17 Feb 2025 11:41:07 -0500 X-MC-Unique: Ghl4AiDdM6Wz8Gl_v4r54Q-1 X-Mimecast-MFC-AGG-ID: Ghl4AiDdM6Wz8Gl_v4r54Q_1739810466 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AFE121801A13; Mon, 17 Feb 2025 16:41:06 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.45.225.252]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 42A8D1800352; Mon, 17 Feb 2025 16:41:01 +0000 (UTC) From: Albert Esteve To: qemu-devel@nongnu.org Cc: slp@redhat.com, stevensd@chromium.org, =?utf-8?q?Alex_Benn=C3=A9e?= , Stefano Garzarella , stefanha@redhat.com, david@redhat.com, hi@alyssa.is, mst@redhat.com, jasowang@redhat.com, Albert Esteve Subject: [PATCH v4 9/9] vhost_user.rst: Add MEM_READ/WRITE messages Date: Mon, 17 Feb 2025 17:40:12 +0100 Message-ID: <20250217164012.246727-10-aesteve@redhat.com> In-Reply-To: <20250217164012.246727-1-aesteve@redhat.com> References: <20250217164012.246727-1-aesteve@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.129.124; envelope-from=aesteve@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=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: 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 Add MEM_READ/WRITE request to the vhost-user spec documentation. Signed-off-by: Albert Esteve --- docs/interop/vhost-user.rst | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst index 96156f1900..9f7a2c4cf7 100644 --- a/docs/interop/vhost-user.rst +++ b/docs/interop/vhost-user.rst @@ -391,6 +391,7 @@ In QEMU the vhost-user message is implemented with the following struct: VhostUserTransferDeviceState transfer_state; VhostUserMMap mmap; VhostUserShMemConfig shmem; + VhostUserMemRWMsg mem_rw; }; } QEMU_PACKED VhostUserMsg; @@ -1938,6 +1939,38 @@ is sent by the front-end. given range shall correspond to the entirety of a valid mapped region. A reply is generated indicating whether unmapping succeeded. +``VHOST_USER_BACKEND_MEM_READ`` + :id: 11 + :equivalent ioctl: N/A + :request payload: ``struct VhostUserMemRWMsg`` + :reply payload: N/A + + When the ``VHOST_USER_PROTOCOL_F_SHMEM`` protocol feature has been + successfully negotiated, this message can be submitted by the backends to + read a memory region that has failed to resolve a translation due to an + incomplete memory table, after another device called + ``VHOST_USER_BACKEND_SHMEM_MAP`` for the same region on a shared + descriptor file. + + This mechanism works as a fallback for resolving those memory + accesses and ensure that DMA works with Shared Memory Regions. + +``VHOST_USER_BACKEND_MEM_WRITE`` + :id: 12 + :equivalent ioctl: N/A + :request payload: ``struct VhostUserMemRWMsg`` + :reply payload: N/A + + When the ``VHOST_USER_PROTOCOL_F_SHMEM`` protocol feature has been + successfully negotiated, this message can be submitted by the backends to + write a memory region that has failed due to resolve a translation an + incomplete memory table after another device called + ``VHOST_USER_BACKEND_SHMEM_MAP`` for the same region on a shared + descriptor file. + + This mechanism works as a fallback for resolving those memory + accesses and ensure that DMA works with Shared Memory Regions. + .. _reply_ack: VHOST_USER_PROTOCOL_F_REPLY_ACK