From ee2ffdf890f46a93f0057ce4205b3b59bd59a596 Mon Sep 17 00:00:00 2001 From: Egor Lazarchuk Date: Mon, 22 Jan 2024 13:38:12 +0000 Subject: [PATCH] doc: add `postcopy` feature description New sections in README files describe what `postcopy` feature enables and the limitation of using it with `xen` feature. Signed-off-by: Egor Lazarchuk --- vhost-user-backend/README.md | 10 ++++++++++ vhost/README.md | 6 ++++++ 2 files changed, 16 insertions(+) diff --git a/vhost-user-backend/README.md b/vhost-user-backend/README.md index a4e51a8..46b771c 100644 --- a/vhost-user-backend/README.md +++ b/vhost-user-backend/README.md @@ -98,6 +98,16 @@ impl VhostUserBackendMut for VhostUserService { } ``` +## Postcopy support + +To enabled POSTCOPY_* messages support there is a `postcopy` feature. +Due to how Xen handles memory mappings the `postcopy` feature is not compatible +with `xen` feature. Enabling both at the same time will result in a compilation error. + +`postcopy` feature enables optional `userfaultfd` dependency in order to create and +interact with `userfaultfd` object. This requires access permission to `/dev/userfaultfd` +file from the backend. + ## Xen support Supporting Xen requires special handling while mapping the guest memory. The diff --git a/vhost/README.md b/vhost/README.md index 1eef3f4..101b4d7 100644 --- a/vhost/README.md +++ b/vhost/README.md @@ -31,6 +31,12 @@ Frontend is the application that shares its virtqueues, backend is the consumer of the virtqueues. Frontend and backend can be either a client (i.e. connecting) or server (listening) in the socket communication. +## Postcopy support + +To enabled POSTCOPY_* messages support there is a `postcopy` feature. +Due to how Xen handles memory mappings the `postcopy` feature is not compatible +with `xen` feature. Enabling both at the same time will result in a compilation error. + ## Xen support Supporting Xen requires special handling while mapping the guest memory. The