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[Qemu-devel] [PULL 10/15] specs/vhost-user: fix spec to match reality
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] [PULL 10/15] specs/vhost-user: fix spec to match reality |
Date: |
Thu, 19 Nov 2015 15:36:28 +0200 |
We wanted to start/stop rings on VRING_ENABLE, but that is not what QEMU
does. Rather than tweaking code some more, with risk to stability, let's
just document it as it is.
We'll be able to fix this in the future with a new protocol feature bit.
Reported-by: Victor Kaplansky <address@hidden>
Signed-off-by: Michael S. Tsirkin <address@hidden>
---
docs/specs/vhost-user.txt | 28 +++++++++++++++++-----------
1 file changed, 17 insertions(+), 11 deletions(-)
diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
index df40cec..7b9cd6d 100644
--- a/docs/specs/vhost-user.txt
+++ b/docs/specs/vhost-user.txt
@@ -148,20 +148,26 @@ a feature bit was dedicated for this purpose:
Starting and stopping rings
----------------------
-Each ring is initialized in a stopped state, client must not process it until
-ring is enabled.
+Client must only process each ring when it is both started and enabled.
+
+If VHOST_USER_F_PROTOCOL_FEATURES has not been negotiated, the ring is
initialized
+in an enabled state.
-If VHOST_USER_F_PROTOCOL_FEATURES has been negotiated, client must start and
-stop ring processing upon receiving VHOST_USER_SET_VRING_ENABLE with parameters
-1 and 0 respoectively.
+If VHOST_USER_F_PROTOCOL_FEATURES has been negotiated, the ring is initialized
+in a disabled state. Client must not process it until ring is enabled by
+VHOST_USER_SET_VRING_ENABLE with parameter 1, or after it has been disabled by
+VHOST_USER_SET_VRING_ENABLE with parameter 0.
+
+Each ring is initialized in a stopped state, client must not process it until
+ring is started, or after it has been stopped.
-If VHOST_USER_F_PROTOCOL_FEATURES has not been negotiated, client must start
-ring processing upon receiving a kick (that is, detecting that file descriptor
-is readable) on the descriptor specified by VHOST_USER_SET_VRING_KICK, and stop
-ring processing upon receiving VHOST_USER_GET_VRING_BASE.
+Client must start ring upon receiving a kick (that is, detecting that file
+descriptor is readable) on the descriptor specified by
+VHOST_USER_SET_VRING_KICK, and stop ring upon receiving
+VHOST_USER_GET_VRING_BASE.
-While rings are running, client must support changing some configuration
-aspects on the fly.
+While processing the rings (when they are started and enabled), client must
+support changing some configuration aspects on the fly.
Multiple queue support
----------------------
--
MST
[Qemu-devel] [PULL 05/15] vhost-user: print original request on error, Michael S. Tsirkin, 2015/11/19
[Qemu-devel] [PULL 09/15] tests/vhost-user-bridge: implement logging of dirty pages, Michael S. Tsirkin, 2015/11/19
[Qemu-devel] [PULL 11/15] vhost-user: ignore qemu-only features, Michael S. Tsirkin, 2015/11/19
[Qemu-devel] [PULL 10/15] specs/vhost-user: fix spec to match reality,
Michael S. Tsirkin <=
[Qemu-devel] [PULL 12/15] vhost-user: fix log size, Michael S. Tsirkin, 2015/11/19
[Qemu-devel] [PULL 13/15] acpi: fix buffer overrun on migration, Michael S. Tsirkin, 2015/11/19
[Qemu-devel] [PULL 14/15] tests: re-enable vhost-user-test, Michael S. Tsirkin, 2015/11/19
[Qemu-devel] [PULL 15/15] exec: silence hugetlbfs warning under qtest, Michael S. Tsirkin, 2015/11/19
Re: [Qemu-devel] [PULL 00/15] vhost, pc: fixes for 2.5, Peter Maydell, 2015/11/19
Re: [Qemu-devel] [PULL 00/15] vhost, pc: fixes for 2.5, Peter Maydell, 2015/11/26