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[174.165.208.10]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-cd3d9e1ee81sm1513576a12.12.2026.10.09.11.41.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Oct 2026 11:41:01 -0700 (PDT) From: Michael Kelley X-Google-Original-From: Michael Kelley To: haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, corbet@lwn.net, skhan@linuxfoundation.org, rdunlap@infradead.org, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-doc@vger.kernel.org Subject: [PATCH v2 1/1] Documentation: hyperv: Update documentation for sending VMBus packets Date: Fri, 9 Oct 2026 11:40:56 -0700 Message-Id: <20261009184056.7382-1-mhklinux@outlook.com> X-Mailer: git-send-email 2.25.1 Reply-To: mhklinux@outlook.com Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The functions for sending VMBus packets have changed. vmbus_sendpacket_mpb_desc() can target multiple ranges, and vmbus_sendpacket_pagebuffer() has been removed. vmbus_sendpacket_getid() has been added. Update the documentation accordingly. Fixes: 45a442fe369e ("Drivers: hv: vmbus: Remove vmbus_sendpacket_pagebuffer()") Cc: stable@vger.kernel.org Signed-off-by: Michael Kelley --- Changes in v2: * Add vmbus_sendpacket_getid() to the documentation. [Naman Jain] Documentation/virt/hyperv/vmbus.rst | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/Documentation/virt/hyperv/vmbus.rst b/Documentation/virt/hyperv/vmbus.rst index 654bb4849972..9c5b712c6e39 100644 --- a/Documentation/virt/hyperv/vmbus.rst +++ b/Documentation/virt/hyperv/vmbus.rst @@ -141,14 +141,15 @@ Three 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_getid(): Similar to vmbus_sendpacket() but returns + a transaction ID that is matched against a reply from the Hyper-V + host. Useful when the struct completion (or other rendezvous data) + must reside on the caller's stack. By invalidating the transaction + ID before exiting the function due to a timeout or other error, a + late arrving interrupt is assured to not trash the stack. +3. 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