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{ "id": 2198135, "url": "http://patchwork.ozlabs.org/api/1.0/covers/2198135/?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": "<20260219130334.787858-1-aesteve@redhat.com>", "date": "2026-02-19T13:03:27", "name": "[v13,0/7] vhost-user: Add SHMEM_MAP/UNMAP requests", "submitter": { "id": 85915, "url": "http://patchwork.ozlabs.org/api/1.0/people/85915/?format=api", "name": "Albert Esteve", "email": "aesteve@redhat.com" }, "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/" } ], "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=cqwUlWme;\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 08:03:52 -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-121-QmxcmrIdNO6OljSux_ipZw-1; Thu,\n 19 Feb 2026 08:03:45 -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 16AE01956088; Thu, 19 Feb 2026 13:03:43 +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 7609D1955F01; Thu, 19 Feb 2026 13:03:36 +0000 (UTC)" ], "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;\n s=mimecast20190719; t=1771506229;\n h=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n to:to:cc:cc:mime-version:mime-version:content-type:content-type:\n content-transfer-encoding:content-transfer-encoding;\n bh=GfnV/zKgRVgL1zzhb9CqiAMAu8czKO3LqF4YsD9cyIE=;\n b=cqwUlWmewmo4lWGTUXZKdEyrSXOXlhoDm/H1M3dZtZXrm7GighzZbbSCbtRI6QPzJKEFdf\n YgTNAoJwoCQQ5DQ9eVWNeOKePTKw8I8UjgNe2NqDxXEIQPwtRssdf3A/4DNJFBRawr0fSN\n 08rwbqLS547QhZhzgwnEBfFkSfUWufg=", "X-MC-Unique": "QmxcmrIdNO6OljSux_ipZw-1", "X-Mimecast-MFC-AGG-ID": "QmxcmrIdNO6OljSux_ipZw_1771506224", "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 0/7] vhost-user: Add SHMEM_MAP/UNMAP requests", "Date": "Thu, 19 Feb 2026 14:03:27 +0100", "Message-ID": "<20260219130334.787858-1-aesteve@redhat.com>", "Content-Type": "text/plain; charset=\"utf-8\"", "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": "Hi all,\n\nv12-v13\n- SMEM_UNMAP spec update to explicitly state the use of\n VHOST_USER_PROTOCOL_F_REPLY_ACK for replies\n- Removed confusing remark for 0-sized regions in\n GET_SHMEM_CONFIG\nv11->v12\n- Refined VIRTIO Shared Memory Region configuration mem size\n spec description\n- Removed unused name in vhost-user-base's vub_device_realize to\n avoid build error\n- Initialize shmem in vhost_user_backend_handle_shmem_unmap\n to avoid compiler being confused\n- Added stub for memory_region_init_ram_from_fd in memory.h\n for windows builds\n- Use memory_region_size for shmem_region handlers instead\n of accessing size member directly in shmem mrs\nv10->v11\n- Rebase to grab commit fde5930cc37175cfcd0f03a089e26f4458a52311\n and explicitly unset reply_ack on the SHMEM_MAP/UNMAP msg.\n- Mention mapping cleanup on device reset in the spec.\nv9->v10\n- Fix transaction_commit invoked without transaction_begin\n on vhost_user_backend_handle_shmem_map() early errors\n- Removed fd tracking on VirtioSharedMemoryMapping, it\n is handled by the RAMBlock\n- Reject invalid BAR configurations when VIRTIO Shared Memory\n Regions are in use by vhost-user-test-device\n\nThis patch series implements dynamic fd-backed memory mapping support\nfor vhost-user backends, enabling backends to dynamically request memory\nmappings and unmappings during runtime through the new\nVHOST_USER_BACKEND_SHMEM_MAP/UNMAP protocol messages.\n\nThis feature benefits various VIRTIO devices that require dynamic shared\nmemory management, including virtiofs (for DAX mappings), virtio-gpu\n(for resource sharing), and the recently standardized virtio-media.\n\nThe implementation introduces a QOM-based architecture for managing\nshared memory lifecycle:\n\n- VirtioSharedMemoryMapping: an intermediate object that manages\n individual memory mappings by acting as generic container for regions\n declared in any vhost-user device type\n- Dynamic Mapping: backends can request mappings via SHMEM_MAP messages,\n with the frontend creating MemoryRegions from the provided file\n descriptors and adding them as subregions\n\nWhen a SHMEM_MAP request is received, the frontend:\n1. Creates VirtioSharedMemoryMapping to manage the mapping lifecycle\n2. Maps the provided fd with memory_region_init_ram_from_fd()\n3. Creates a MemoryRegion backed by the mapped memory\n4. Adds it as a subregion of the appropiate VIRTIO Shared Memory Region\n\nThe QOM reference counting ensures automatic cleanup when mappings are\nremoved or the device is destroyed.\n\nThis patch also includes:\n- VHOST_USER_GET_SHMEM_CONFIG: a new frontend request allowing generic\n vhost-user devices to query shared memory configuration from backends\n at device initialization, enabling the generic vhost-user-device\n frontend to work with any backend regardless of specific shared memory\n requirements.\n\nThe implementation has been tested with rust-vmm based backends.\n\nAlbert Esteve (7):\n vhost-user: Add VirtIO Shared Memory map request\n vhost_user.rst: Align VhostUserMsg excerpt members\n vhost_user.rst: Add SHMEM_MAP/_UNMAP to spec\n vhost_user: Add frontend get_shmem_config command\n vhost_user.rst: Add GET_SHMEM_CONFIG message\n qmp: add shmem feature map\n vhost-user-device: Add shared memory BAR\n\n docs/interop/vhost-user.rst | 104 +++++++++\n hw/virtio/vhost-user-base.c | 46 +++-\n hw/virtio/vhost-user-test-device-pci.c | 38 ++-\n hw/virtio/vhost-user.c | 269 ++++++++++++++++++++++\n hw/virtio/virtio-qmp.c | 3 +\n hw/virtio/virtio.c | 201 ++++++++++++++++\n include/hw/virtio/vhost-backend.h | 10 +\n include/hw/virtio/vhost-user.h | 1 +\n include/hw/virtio/virtio.h | 137 +++++++++++\n include/system/memory.h | 13 ++\n subprojects/libvhost-user/libvhost-user.c | 70 ++++++\n subprojects/libvhost-user/libvhost-user.h | 54 +++++\n 12 files changed, 941 insertions(+), 5 deletions(-)" }