netvsp: handle RNDIS packet filter OID for stopping Rx (#1873) #1927
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Linux netvsc sends an OID to stop receiving packets on vmbus channel close. Example scenarios: hibernation and MTU change. Prior to opening a new channel and processing the packets, netvsc checks that there are no pending packets. If there are, netvsc logs and error and is unable to recover. We observe the error: `hv_netvsc eth0: Ring buffer not empty after closing rndis` in the guest syslog. Modifying netvsp to handle the OID and stop processing RX traffic. This will allow for netvsc to successfully close and re-open the vmbus channel, even under heavy incoming traffic. --------- Co-authored-by: Sunil Muthuswamy <[email protected]>
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Pull Request Overview
This PR adds handling for the RNDIS packet filter OID (OID_GEN_CURRENT_PACKET_FILTER) to the netvsp driver to support proper vmbus channel closure scenarios. When Linux netvsc needs to close and reopen a vmbus channel (during hibernation or MTU changes), it sends an OID to stop receiving packets, which was previously unhandled and caused channel recovery failures.
Key changes:
- Implements packet filter OID handling to allow stopping/starting RX traffic
- Adds packet filter state tracking across channel restore operations
- Updates coordinator messaging to propagate filter changes across subchannels
Reviewed Changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.
| File | Description |
|---|---|
| vm/devices/net/netvsp/src/lib.rs | Core implementation of packet filter handling, state management, and coordinator updates |
| vm/devices/net/netvsp/src/rndisprot.rs | Adds packet filter constants and OID definitions |
| vm/devices/net/netvsp/src/saved_state.rs | Extends saved state to include packet filter for persistence |
| vm/devices/net/netvsp/src/test.rs | Comprehensive test coverage for packet filter functionality |
Brian-Perkins
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Aug 27, 2025
chris-oo
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Aug 28, 2025
benhillis
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Sep 3, 2025
benhillis
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Sep 3, 2025
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Linux netvsc sends an OID to stop receiving packets on vmbus channel close. Example scenarios: hibernation and MTU change. Prior to opening a new channel and processing the packets, netvsc checks that there are no pending packets. If there are, netvsc logs and error and is unable to recover. We observe the error:
hv_netvsc eth0: Ring buffer not empty after closing rndisin the guest syslog.Modifying netvsp to handle the OID and stop processing RX traffic. This will allow for netvsc to successfully close and re-open the vmbus channel, even under heavy incoming traffic.
Cherry pick of #1873