From nobody Sat Nov 15 17:43:57 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=quarantine dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1749480605; cv=none; d=zohomail.com; s=zohoarc; b=NpLPSb3nbchK7YAqyzMCPN/Bxo1vJfiwgkl+zyzLAw+g5c1uHQr9bTirXiK1h/B7HCyMzCJiugN/V0N1HXLueKgcQdLWy1BPZZGHX1zxYBeRziiNrWbq9gWTtE5KhvHD6RGHoCEypz4twckl4vejAjv6seKF/yfaBoR6QgMgDAU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1749480605; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=ZvOd00GowewmzBnbnqRYjZuswI4gvnr0bfGLIS0ijts=; b=NF6odxH9dsdJFk7gYsM6L3F4yS4i6sfS4kFa6f1BbnH2wYAjzrr9GDss1VRNt31mcxB5IjvL+GSL/doMzmsK62v+1bZm+tAMoG2/egt8Fa50U3c1BOkUMsn02ShbdvLaaEfbishG1K2Y5Lo+5VrFEe8mWkiOl0tLVJ5/WE3bev0= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=quarantine dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1749480605264781.0118633783164; Mon, 9 Jun 2025 07:50:05 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uOdoP-0005Oj-5U; Mon, 09 Jun 2025 10:49:21 -0400 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 1uOdoA-0005Jd-C5 for qemu-devel@nongnu.org; Mon, 09 Jun 2025 10:49:07 -0400 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 1uOdo8-0008P1-8z for qemu-devel@nongnu.org; Mon, 09 Jun 2025 10:49:05 -0400 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-235-spJQ8L0bPRKXzf7ytvzLQg-1; Mon, 09 Jun 2025 10:47:53 -0400 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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 1FA5E1808985; Mon, 9 Jun 2025 14:47:52 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.44.33.48]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 8F76319560A3; Mon, 9 Jun 2025 14:47:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1749480543; 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=ZvOd00GowewmzBnbnqRYjZuswI4gvnr0bfGLIS0ijts=; b=Yor0BpSamK/UrGvm5nBkn+tBNq0bDAt5x4Qh0YSVrh2qy5PWZ6Z57hLW74RpNY/sYBSwqo fOGMRaM3/kvYAXN3SRU45JpAcxki8Rlo11et27+iasx2+uj1cnGtFrnJZ2SPslEF+5A4Bc 5bhCDiTbaQWDrLE3YezSmip7asuDegY= X-MC-Unique: spJQ8L0bPRKXzf7ytvzLQg-1 X-Mimecast-MFC-AGG-ID: spJQ8L0bPRKXzf7ytvzLQg_1749480472 From: Albert Esteve To: qemu-devel@nongnu.org Cc: stefanha@redhat.com, slp@redhat.com, david@redhat.com, "Michael S. Tsirkin" , Stefano Garzarella , jasowang@redhat.com, stevensd@chromium.org, hi@alyssa.is, =?UTF-8?q?Alex=20Benn=C3=A9e?= , Albert Esteve Subject: [PATCH v5 3/7] vhost_user.rst: Add SHMEM_MAP/_UNMAP to spec Date: Mon, 9 Jun 2025 16:47:25 +0200 Message-ID: <20250609144729.884027-4-aesteve@redhat.com> In-Reply-To: <20250609144729.884027-1-aesteve@redhat.com> References: <20250609144729.884027-1-aesteve@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; 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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1749480608422116600 Content-Type: text/plain; charset="utf-8" Add SHMEM_MAP/_UNMAP request to the vhost-user spec documentation. Reviewed-by: Stefan Hajnoczi Signed-off-by: Albert Esteve --- docs/interop/vhost-user.rst | 55 +++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst index 436a94c0ee..b623284819 100644 --- a/docs/interop/vhost-user.rst +++ b/docs/interop/vhost-user.rst @@ -350,6 +350,27 @@ Device state transfer parameters In the future, additional phases might be added e.g. to allow iterative migration while the device is running. =20 +MMAP request +^^^^^^^^^^^^ + ++-------+---------+-----------+------------+-----+-------+ +| shmid | padding | fd_offset | shm_offset | len | flags | ++-------+---------+-----------+------------+-----+-------+ + +:shmid: a 8-bit shared memory region identifier + +:fd_offset: a 64-bit offset of this area from the start + of the supplied file descriptor + +:shm_offset: a 64-bit offset from the start of the + pointed shared memory region + +:len: a 64-bit size of the memory to map + +:flags: a 64-bit value: + - 0: Pages are mapped read-only + - 1: Pages are mapped read-write + C structure ----------- =20 @@ -375,6 +396,7 @@ In QEMU the vhost-user message is implemented with the = following struct: VhostUserInflight inflight; VhostUserShared object; VhostUserTransferDeviceState transfer_state; + VhostUserMMap mmap; }; } QEMU_PACKED VhostUserMsg; =20 @@ -1057,6 +1079,7 @@ Protocol features #define VHOST_USER_PROTOCOL_F_XEN_MMAP 17 #define VHOST_USER_PROTOCOL_F_SHARED_OBJECT 18 #define VHOST_USER_PROTOCOL_F_DEVICE_STATE 19 + #define VHOST_USER_PROTOCOL_F_SHMEM 20 =20 Front-end message types ----------------------- @@ -1865,6 +1888,38 @@ is sent by the front-end. when the operation is successful, or non-zero otherwise. Note that if the operation fails, no fd is sent to the backend. =20 +``VHOST_USER_BACKEND_SHMEM_MAP`` + :id: 9 + :equivalent ioctl: N/A + :request payload: fd and ``struct VhostUserMMap`` + :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 + advertise a new mapping to be made in a given VIRTIO Shared Memory Regio= n. + Upon receiving the message, the front-end will mmap the given fd into the + VIRTIO Shared Memory Region with the requested ``shmid``. A reply is + generated indicating whether mapping succeeded. + + Mapping over an already existing map is not allowed and request shall fa= il. + Therefore, the memory range in the request must correspond with a valid, + free region of the VIRTIO Shared Memory Region. Also, note that mappings + consume resources and that the request can fail when there are no resour= ces + available. + +``VHOST_USER_BACKEND_SHMEM_UNMAP`` + :id: 10 + :equivalent ioctl: N/A + :request payload: ``struct VhostUserMMap`` + :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 so + that the front-end un-mmap a given range (``shm_offset``, ``len``) in the + VIRTIO Shared Memory Region with the requested ``shmid``. Note that the + given range shall correspond to the entirety of a valid mapped region. + A reply is generated indicating whether unmapping succeeded. + .. _reply_ack: =20 VHOST_USER_PROTOCOL_F_REPLY_ACK --=20 2.49.0