[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PATCH 1/3] vhost_user.rst: Add SHMEM_MAP/_UNMAP to spec
From: |
Albert Esteve |
Subject: |
[PATCH 1/3] vhost_user.rst: Add SHMEM_MAP/_UNMAP to spec |
Date: |
Thu, 12 Sep 2024 16:44:30 +0200 |
Add SHMEM_MAP/_UNMAP request to the vhost-user
spec documentation.
Signed-off-by: Albert Esteve <aesteve@redhat.com>
---
docs/interop/vhost-user.rst | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst
index d8419fd2f1..d680fea4a3 100644
--- a/docs/interop/vhost-user.rst
+++ b/docs/interop/vhost-user.rst
@@ -369,6 +369,7 @@ In QEMU the vhost-user message is implemented with the
following struct:
VhostUserConfig config;
VhostUserVringArea area;
VhostUserInflight inflight;
+ VhostUserMMap mmap;
};
} QEMU_PACKED VhostUserMsg;
@@ -1859,6 +1860,36 @@ 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.
+``VHOST_USER_BACKEND_SHMEM_MAP``
+ :id: 9
+ :equivalent ioctl: N/A
+ :request payload: fd and ``struct VhostUserMMap``
+ :reply payload: N/A
+
+ This message can be submitted by the backends to advertise a new mapping
+ to be made in a given VIRTIO Shared Memory Region. 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 fail.
+ 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 resources
+ available.
+
+``VHOST_USER_BACKEND_SHMEM_UNMAP``
+ :id: 10
+ :equivalent ioctl: N/A
+ :request payload: ``struct VhostUserMMap``
+ :reply payload: N/A
+
+ 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:
VHOST_USER_PROTOCOL_F_REPLY_ACK
--
2.45.2