kernel/linux.git/drivers/hv/connection.c, branch v5.15.208

Drivers: vmbus: Check for channel allocation before looking up relids

2023-04-13T14:48:17+00:00

[ Upstream commit 1eb65c8687316c65140b48fad27133d583178e15 ] relid2channel() assumes vmbus channel array to be allocated when called. However, in cases such as kdump/kexec, not all relids will be reset by the host. When the second kernel boots and if the guest receives a vmbus interrupt during vmbus driver initialization before vmbus_connect() is called, before it finishes, or if it fails, the vmbus interrupt service routine is called which in turn calls relid2channel() and can cause a null pointer dereference. Print a warning and error out in relid2channel() for a channel id that's invalid in the second kernel. Fixes: 8b6a877c060e ("Drivers: hv: vmbus: Replace the per-CPU channel lists with a global array of channels") Signed-off-by: Mohammed Gamal Reviewed-by: Dexuan Cui Link: https://lore.kernel.org/r/20230217204411.212709-1-mgamal@redhat.com Signed-off-by: Wei Liu Signed-off-by: Sasha Levin

drivers: hv: Fix missing error code in vmbus_connect()

2021-06-02T15:16:36+00:00

Eliminate the follow smatch warning: drivers/hv/connection.c:236 vmbus_connect() warn: missing error code 'ret'. Reported-by: Abaci Robot Signed-off-by: Jiapeng Chong Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/1621940321-72353-1-git-send-email-jiapeng.chong@linux.alibaba.com Signed-off-by: Wei Liu

Drivers: hv: vmbus: Initialize unload_event statically

2021-04-20T19:40:17+00:00

If a malicious or compromised Hyper-V sends a spurious message of type CHANNELMSG_UNLOAD_RESPONSE, the function vmbus_unload_response() will call complete() on an uninitialized event, and cause an oops. Reported-by: Michael Kelley Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20210420014350.2002-1-parri.andrea@gmail.com Signed-off-by: Wei Liu

Drivers: hv: vmbus: Introduce and negotiate VMBus protocol version 5.3

2021-04-18T13:03:11+00:00

Hyper-V has added VMBus protocol version 5.3. Allow Linux guests to negotiate the new version on version of Hyper-V that support it. Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20210416143449.16185-2-parri.andrea@gmail.com Signed-off-by: Wei Liu

drivers: hv: Fix whitespace errors

2021-03-08T17:32:58+00:00

Fixed checkpatch warning and errors on hv driver. Signed-off-by: Vasanth Mathivanan Link: https://lore.kernel.org/r/20210219171311.421961-1-vasanth3g@gmail.com Reviewed-by: Michael Kelley Signed-off-by: Wei Liu

Drivers: hv: vmbus: Enforce 'VMBus version >= 5.2' on isolated guests

2021-02-11T08:47:05+00:00

Restrict the protocol version(s) that will be negotiated with the host to be 5.2 or greater if the guest is running isolated. This reduces the footprint of the code that will be exercised by Confidential VMs and hence the exposure to bugs and vulnerabilities. Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20210201144814.2701-4-parri.andrea@gmail.com Signed-off-by: Wei Liu

Drivers: hv: vmbus: Replace the per-CPU channel lists with a global array of channels

2020-04-23T13:17:11+00:00

When Hyper-V sends an interrupt to the guest, the guest has to figure out which channel the interrupt is associated with. Hyper-V sets a bit in a memory page that is shared with the guest, indicating a particular "relid" that the interrupt is associated with. The current Linux code then uses a set of per-CPU linked lists to map a given "relid" to a pointer to a channel structure. This design introduces a synchronization problem if the CPU that Hyper-V will interrupt for a certain channel is changed. If the interrupt comes on the "old CPU" and the channel was already moved to the per-CPU list of the "new CPU", then the relid -> channel mapping will fail and the interrupt is dropped. Similarly, if the interrupt comes on the new CPU but the channel was not moved to the per-CPU list of the new CPU, then the mapping will fail and the interrupt is dropped. Relids are integers ranging from 0 to 2047. The mapping from relids to channel structures can be done by setting up an array with 2048 entries, each entry being a pointer to a channel structure (hence total size ~16K bytes, which is not a problem). The array is global, so there are no per-CPU linked lists to update. The array can be searched and updated by loading from/storing to the array at the specified index. With no per-CPU data structures, the above mentioned synchronization problem is avoided and the relid2channel() function gets simpler. Suggested-by: Michael Kelley Signed-off-by: Andrea Parri (Microsoft) Link: https://lore.kernel.org/r/20200406001514.19876-4-parri.andrea@gmail.com Reviewed-by: Michael Kelley Signed-off-by: Wei Liu

Drivers: hv: vmbus: Always handle the VMBus messages on CPU0

2020-04-23T13:17:11+00:00

A Linux guest have to pick a "connect CPU" to communicate with the Hyper-V host. This CPU can not be taken offline because Hyper-V does not provide a way to change that CPU assignment. Current code sets the connect CPU to whatever CPU ends up running the function vmbus_negotiate_version(), and this will generate problems if that CPU is taken offine. Establish CPU0 as the connect CPU, and add logics to prevents the connect CPU from being taken offline. We could pick some other CPU, and we could pick that "other CPU" dynamically if there was a reason to do so at some point in the future. But for now, #defining the connect CPU to 0 is the most straightforward and least complex solution. While on this, add inline comments explaining "why" offer and rescind messages should not be handled by a same serialized work queue. Suggested-by: Dexuan Cui Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Vitaly Kuznetsov Link: https://lore.kernel.org/r/20200406001514.19876-2-parri.andrea@gmail.com Reviewed-by: Michael Kelley Signed-off-by: Wei Liu

Drivers: hv: vmbus: Remove dependencies on guest page size

2019-11-22T01:10:45+00:00

Hyper-V assumes page size to be 4K. This might not be the case for ARM64 architecture. Hence use hyper-v page size and page allocation function to avoid conflicts between different host and guest page size on ARM64. Signed-off-by: Himadri Pandya Reviewed-by: Michael Kelley Signed-off-by: Sasha Levin

drivers: hv: vmbus: Introduce latency testing

2019-11-22T01:10:44+00:00

Introduce user specified latency in the packet reception path By exposing the test parameters as part of the debugfs channel attributes. We will control the testing state via these attributes. Signed-off-by: Branden Bonaby Reviewed-by: Michael Kelley Signed-off-by: Sasha Levin