From: Sergio Lopez Date: Fri, 4 Mar 2022 10:08:54 +0000 (+0100) Subject: docs: vhost-user: add subsection for non-Linux platforms X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=b51082905faededb32f57e380446e919a42b9017;p=qmiga%2Fqemu.git docs: vhost-user: add subsection for non-Linux platforms Add a section explaining how vhost-user is supported on platforms other than Linux. Signed-off-by: Sergio Lopez Reviewed-by: Stefan Hajnoczi Message-Id: <20220304100854.14829-5-slp@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst index edc3ad84a3..4dbc84fd00 100644 --- a/docs/interop/vhost-user.rst +++ b/docs/interop/vhost-user.rst @@ -38,6 +38,26 @@ conventions `. *Master* and *slave* can be either a client (i.e. connecting) or server (listening) in the socket communication. +Support for platforms other than Linux +-------------------------------------- + +While vhost-user was initially developed targeting Linux, nowadays it +is supported on any platform that provides the following features: + +- A way for requesting shared memory represented by a file descriptor + so it can be passed over a UNIX domain socket and then mapped by the + other process. + +- AF_UNIX sockets with SCM_RIGHTS, so QEMU and the other process can + exchange messages through it, including ancillary data when needed. + +- Either eventfd or pipe/pipe2. On platforms where eventfd is not + available, QEMU will automatically fall back to pipe2 or, as a last + resort, pipe. Each file descriptor will be used for receiving or + sending events by reading or writing (respectively) an 8-byte value + to the corresponding it. The 8-value itself has no meaning and + should not be interpreted. + Message Specification =====================