[PATCH 1/1] Documentation: hyperv: Update documentation for sending VMBus packets

From: Michael Kelley

Date: Thu Oct 08 2026 - 23:07:58 EST


The functions for sending VMBus packets have been simplified.
vmbus_sendpacket_mpb_desc() can target multiple ranges, and
vmbus_sendpacket_pagebuffer() has been removed. Update the
documentation accordingly.

Fixes: 45a442fe369e ("Drivers: hv: vmbus: Remove vmbus_sendpacket_pagebuffer()")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
---
The Fixes: tag reflects the code change that was made. The
documentation update should have been included with the
original code change.

Documentation/virt/hyperv/vmbus.rst | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/Documentation/virt/hyperv/vmbus.rst b/Documentation/virt/hyperv/vmbus.rst
index 654bb4849972..77a437969b49 100644
--- a/Documentation/virt/hyperv/vmbus.rst
+++ b/Documentation/virt/hyperv/vmbus.rst
@@ -137,18 +137,13 @@ control message contains a list of GPAs that describe the data
buffer. For example, the storvsc driver uses this approach to
specify the data buffers to/from which disk I/O is done.

-Three functions exist to send VMBus channel messages:
+Two functions exist to send VMBus channel messages:

1. vmbus_sendpacket(): Control-only messages and messages with
embedded data -- no GPAs
-2. vmbus_sendpacket_pagebuffer(): Message with list of GPAs
- identifying data to transfer. An offset and length is
- associated with each GPA so that multiple discontinuous areas
- of guest memory can be targeted.
-3. vmbus_sendpacket_mpb_desc(): Message with list of GPAs
- identifying data to transfer. A single offset and length is
- associated with a list of GPAs. The GPAs must describe a
- single logical area of guest memory to be targeted.
+2. vmbus_sendpacket_mpb_desc(): Message with one or more data ranges
+ to target. Each range consists of a single offset and length plus
+ a list of GPAs that describe a logical area of guest memory.

Historically, Linux guests have trusted Hyper-V to send well-formed
and valid messages, and Linux drivers for synthetic devices did not
--
2.25.1