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c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1772643190; 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=POIGA0TdhwgOcV5gif+U97gr41z8jC9z2Bscrr2zLow=; b=euamUJaGZPIlQ+wE0KAYVsjS3l5J+TKskg0znR9t455ugcv9qwb8O07JC9UrWly1FFtZkj P6lCgByMH2uEUmaImrrND81JUYT3KCl8dqDDZrFKFXahewVmye9b4SfhpUJj8QEqXLTVJO xQ5Yel8/SXxgEFbTx+4PJu5JEaaKAQw= X-MC-Unique: hXcbmq_mPi6iGmU8Uff1ZQ-1 X-Mimecast-MFC-AGG-ID: hXcbmq_mPi6iGmU8Uff1ZQ_1772643186 From: Albert Esteve To: qemu-devel@nongnu.org Cc: mst@redhat.com, Stefano Garzarella , manos.pitsidianakis@linaro.org, slp@redhat.com, =?UTF-8?q?Alex=20Benn=C3=A9e?= , stefanha@redhat.com, stevensd@chromium.org, Laurent Vivier , jasowang@redhat.com, Peter Xu , hi@alyssa.is, Pierrick Bouvier , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Fabiano Rosas , dbassey@redhat.com, Paolo Bonzini Subject: [PATCH v14 5/7] vhost_user.rst: Add GET_SHMEM_CONFIG message Date: Wed, 4 Mar 2026 17:52:21 +0100 Message-ID: <20260304165223.2166175-6-aesteve@redhat.com> In-Reply-To: <20260304165223.2166175-1-aesteve@redhat.com> References: <20260304165223.2166175-1-aesteve@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; 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charset="utf-8" Add GET_SHMEM_CONFIG vhost-user frontend message to the spec documentation. Reviewed-by: Stefano Garzarella Reviewed-by: Alyssa Ross Reviewed-by: Stefan Hajnoczi Signed-off-by: Albert Esteve --- docs/interop/vhost-user.rst | 39 +++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst index 08a5e43988..4ee663d10b 100644 --- a/docs/interop/vhost-user.rst +++ b/docs/interop/vhost-user.rst @@ -371,6 +371,22 @@ MMAP request - 0: Pages are mapped read-only - 1: Pages are mapped read-write =20 +VIRTIO Shared Memory Region configuration +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + ++-------------+---------+------------+----+--------------+ +| num regions | padding | mem size 0 | .. | mem size 255 | ++-------------+---------+------------+----+--------------+ + +:num regions: a 32-bit number of regions + +:padding: 32-bit + +:mem size: an array of 256 64-bit fields representing the size of each + VIRTIO Shared Memory Region. ``num regions`` specifies the + number of valid regions (non-zero size). The array index + corresponds to the shared memory ID (shmid). + C structure ----------- =20 @@ -397,6 +413,7 @@ In QEMU the vhost-user message is implemented with the = following struct: VhostUserShared object; VhostUserTransferDeviceState transfer_state; VhostUserMMap mmap; + VhostUserShMemConfig shmem; }; } QEMU_PACKED VhostUserMsg; =20 @@ -1777,6 +1794,28 @@ Front-end message types Using this function requires prior negotiation of the ``VHOST_USER_PROTOCOL_F_DEVICE_STATE`` feature. =20 +``VHOST_USER_GET_SHMEM_CONFIG`` + :id: 44 + :equivalent ioctl: N/A + :request payload: N/A + :reply payload: ``struct VhostUserShMemConfig`` + + When the ``VHOST_USER_PROTOCOL_F_SHMEM`` protocol feature has been + successfully negotiated, this message can be submitted by the front-end + to gather the VIRTIO Shared Memory Region configuration. The back-end wi= ll + respond with the number of VIRTIO Shared Memory Regions it requires, and + each shared memory region size in an array. The shared memory IDs are + represented by the array index. The information returned shall comply + with the following rules: + + * The shared information will remain valid and unchanged for the entire + lifetime of the connection. + + * The Shared Memory Region size must be a multiple of the page size + supported by mmap(2). + + * The size may be 0 if the region is unused. + Back-end message types ---------------------- =20 --=20 2.52.0