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GET /api/1.0/patches/2198136/?format=api
{ "id": 2198136, "url": "http://patchwork.ozlabs.org/api/1.0/patches/2198136/?format=api", "project": { "id": 14, "url": "http://patchwork.ozlabs.org/api/1.0/projects/14/?format=api", "name": "QEMU Development", "link_name": "qemu-devel", "list_id": "qemu-devel.nongnu.org", "list_email": "qemu-devel@nongnu.org", "web_url": "", "scm_url": "", "webscm_url": "" }, "msgid": "<20260219130334.787858-4-aesteve@redhat.com>", "date": "2026-02-19T13:03:30", "name": "[v13,3/7] vhost_user.rst: Add SHMEM_MAP/_UNMAP to spec", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "5330b7af42b99395d0789866fbe0a66e8a4889ad", "submitter": { "id": 85915, "url": "http://patchwork.ozlabs.org/api/1.0/people/85915/?format=api", "name": "Albert Esteve", "email": "aesteve@redhat.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260219130334.787858-4-aesteve@redhat.com/mbox/", "series": [ { "id": 492672, "url": "http://patchwork.ozlabs.org/api/1.0/series/492672/?format=api", "date": "2026-02-19T13:03:27", "name": "vhost-user: Add SHMEM_MAP/UNMAP requests", "version": 13, "mbox": "http://patchwork.ozlabs.org/series/492672/mbox/" } ], "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2198136/checks/", "tags": {}, "headers": { "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>", "X-Original-To": "incoming@patchwork.ozlabs.org", "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=PKYjlrlj;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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Thu, 19 Feb 2026 08:04:10 -0500", "from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com\n (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by\n relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3,\n cipher=TLS_AES_256_GCM_SHA384) id us-mta-563-xMDpuZQSMIKUB2q0hilJxg-1; Thu,\n 19 Feb 2026 08:04:05 -0500", "from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com\n (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12])\n (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest\n SHA256)\n (No client certificate requested)\n by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS\n id 7B061195609E; Thu, 19 Feb 2026 13:04:03 +0000 (UTC)", "from fedora.redhat.com (unknown [10.44.33.19])\n by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP\n id 3CA6A19560A7; Thu, 19 Feb 2026 13:03:56 +0000 (UTC)" ], "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;\n s=mimecast20190719; t=1771506248;\n h=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n to:to:cc:cc:mime-version:mime-version:\n content-transfer-encoding:content-transfer-encoding:\n in-reply-to:in-reply-to:references:references;\n bh=xrDVJ9/PE/1violyKlt4ifA2uIEJBTc29t2K04NQynE=;\n b=PKYjlrlj2a44GHlZXYcroi3i1Kf+yu26c0AymFmS2xM9JsyS0ZjbrmcQ2BN2yAbQYieSya\n 45oKBAuja5YdiKfLtrQjMpSO0dMzUaZhfHfXErbk9YcL/xVRdG9+mf5jwUF/Oi+UXO7R7V\n SAxNrixS5nP0vnO+qfk2/Dvb5JhioM4=", "X-MC-Unique": "xMDpuZQSMIKUB2q0hilJxg-1", "X-Mimecast-MFC-AGG-ID": "xMDpuZQSMIKUB2q0hilJxg_1771506244", "From": "Albert Esteve <aesteve@redhat.com>", "To": "qemu-devel@nongnu.org", "Cc": "Peter Xu <peterx@redhat.com>,\n Pierrick Bouvier <pierrick.bouvier@linaro.org>, mst@redhat.com,\n dbassey@redhat.com,\n =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= <philmd@linaro.org>, =?utf-8?q?Alex?=\n\t=?utf-8?q?_Benn=C3=A9e?= <alex.bennee@linaro.org>,\n Paolo Bonzini <pbonzini@redhat.com>, Fabiano Rosas <farosas@suse.de>,\n stefanha@redhat.com, manos.pitsidianakis@linaro.org,\n Stefano Garzarella <sgarzare@redhat.com>, jasowang@redhat.com,\n Laurent Vivier <lvivier@redhat.com>, slp@redhat.com, hi@alyssa.is,\n stevensd@chromium.org", "Subject": "[PATCH v13 3/7] vhost_user.rst: Add SHMEM_MAP/_UNMAP to spec", "Date": "Thu, 19 Feb 2026 14:03:30 +0100", "Message-ID": "<20260219130334.787858-4-aesteve@redhat.com>", "In-Reply-To": "<20260219130334.787858-1-aesteve@redhat.com>", "References": "<20260219130334.787858-1-aesteve@redhat.com>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-Scanned-By": "MIMEDefang 3.0 on 10.30.177.12", "Received-SPF": "pass client-ip=170.10.129.124; envelope-from=aesteve@redhat.com;\n 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=-0.045,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001,\n RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001,\n RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001,\n SPF_HELO_PASS=-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 <qemu-devel.nongnu.org>", "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>", "List-Archive": "<https://lists.nongnu.org/archive/html/qemu-devel>", "List-Post": "<mailto:qemu-devel@nongnu.org>", "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>", "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=subscribe>", "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org", "Sender": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org" }, "content": "Add SHMEM_MAP/_UNMAP request to the vhost-user\nspec documentation.\n\nReviewed-by: Stefan Hajnoczi <stefanha@redhat.com>\nReviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>\nSigned-off-by: Albert Esteve <aesteve@redhat.com>\n---\n docs/interop/vhost-user.rst | 61 +++++++++++++++++++++++++++++++++++++\n 1 file changed, 61 insertions(+)", "diff": "diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst\nindex 17a68a62eb..ae4ad6f441 100644\n--- a/docs/interop/vhost-user.rst\n+++ b/docs/interop/vhost-user.rst\n@@ -350,6 +350,27 @@ Device state transfer parameters\n In the future, additional phases might be added e.g. to allow\n iterative migration while the device is running.\n \n+MMAP request\n+^^^^^^^^^^^^\n+\n++-------+---------+-----------+------------+-----+-------+\n+| shmid | padding | fd_offset | shm_offset | len | flags |\n++-------+---------+-----------+------------+-----+-------+\n+\n+:shmid: a 8-bit shared memory region identifier\n+\n+:fd_offset: a 64-bit offset of this area from the start\n+ of the supplied file descriptor\n+\n+:shm_offset: a 64-bit offset from the start of the\n+ pointed shared memory region\n+\n+:len: a 64-bit size of the memory to map\n+\n+:flags: a 64-bit value:\n+ - 0: Pages are mapped read-only\n+ - 1: Pages are mapped read-write\n+\n C structure\n -----------\n \n@@ -375,6 +396,7 @@ In QEMU the vhost-user message is implemented with the following struct:\n VhostUserInflight inflight;\n VhostUserShared object;\n VhostUserTransferDeviceState transfer_state;\n+ VhostUserMMap mmap;\n };\n } QEMU_PACKED VhostUserMsg;\n \n@@ -1064,6 +1086,7 @@ Protocol features\n #define VHOST_USER_PROTOCOL_F_XEN_MMAP 17\n #define VHOST_USER_PROTOCOL_F_SHARED_OBJECT 18\n #define VHOST_USER_PROTOCOL_F_DEVICE_STATE 19\n+ #define VHOST_USER_PROTOCOL_F_SHMEM 20\n \n Front-end message types\n -----------------------\n@@ -1872,6 +1895,44 @@ is sent by the front-end.\n when the operation is successful, or non-zero otherwise. Note that if the\n operation fails, no fd is sent to the backend.\n \n+``VHOST_USER_BACKEND_SHMEM_MAP``\n+ :id: 9\n+ :equivalent ioctl: N/A\n+ :request payload: fd and ``struct VhostUserMMap``\n+ :reply payload: N/A\n+\n+ When the ``VHOST_USER_PROTOCOL_F_SHMEM`` protocol feature has been\n+ successfully negotiated, this message can be submitted by the backends to\n+ advertise a new mapping to be made in a given VIRTIO Shared Memory Region.\n+ Upon receiving the message, the front-end will mmap the given fd into the\n+ VIRTIO Shared Memory Region with the requested ``shmid``.\n+ If ``VHOST_USER_PROTOCOL_F_REPLY_ACK`` is negotiated, and\n+ back-end set the ``VHOST_USER_NEED_REPLY`` flag, the front-end\n+ must respond with zero when operation is successfully completed,\n+ or non-zero otherwise.\n+\n+ Mapping over an already existing map is not allowed and requests shall fail.\n+ Therefore, the memory range in the request must correspond with a valid,\n+ free region of the VIRTIO Shared Memory Region. Also, note that mappings\n+ consume resources and that the request can fail when there are no resources\n+ available. Lastly, mappings are automatically unmapped by the front-end\n+ across device reset operation.\n+\n+``VHOST_USER_BACKEND_SHMEM_UNMAP``\n+ :id: 10\n+ :equivalent ioctl: N/A\n+ :request payload: ``struct VhostUserMMap``\n+ :reply payload: N/A\n+\n+ When the ``VHOST_USER_PROTOCOL_F_SHMEM`` protocol feature has been\n+ successfully negotiated, this message can be submitted by the backends so\n+ that the front-end un-mmaps a given range (``shm_offset``, ``len``) in the\n+ VIRTIO Shared Memory Region with the requested ``shmid``. Note that the\n+ given range shall correspond to the entirety of a valid mapped region.\n+ If ``VHOST_USER_PROTOCOL_F_REPLY_ACK`` is negotiated, and the back-end\n+ sets the ``VHOST_USER_NEED_REPLY`` flag, the front-end must respond with\n+ zero when operation is successfully completed, or non-zero otherwise.\n+\n .. _reply_ack:\n \n VHOST_USER_PROTOCOL_F_REPLY_ACK\n", "prefixes": [ "v13", "3/7" ] }