netvsp: handle RNDIS packet filter OID for stopping Rx #1873

erfrimod · 2025-08-15T22:50:19Z

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.

Copilot

Pull Request Overview

This PR implements handling for RNDIS packet filter OID to stop receiving packets when the VMBus channel is being closed. This addresses an issue where Linux netvsc cannot successfully close and reopen channels under heavy traffic, leading to "Ring buffer not empty after closing rndis" errors.

Key changes:

Added stop_rx state tracking throughout the network stack
Implemented OID_GEN_CURRENT_PACKET_FILTER handling to set the stop_rx flag
Modified packet reception logic to respect the stop_rx flag

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
saved_state.rs	Added `stop_rx` field to ReadyPrimary struct for state persistence
rndisprot.rs	Added OID_REQUEST constant and RndisPacketFilterOidValue type for RNDIS protocol support
lib.rs	Implemented stop_rx state management across channels, OID handling, and packet processing logic

vm/devices/net/netvsp/src/lib.rs

github-actions · 2025-08-15T23:32:49Z

At least one Petri test failed.

vm/devices/net/netvsp/src/lib.rs

jstarks · 2025-08-16T19:06:36Z

vm/devices/net/netvsp/src/lib.rs

        let mut restart_endpoint = false;
+        let mut stop_rx = false;
        match oid {
            rndisprot::Oid::OID_GEN_CURRENT_PACKET_FILTER => {


Should we support reading the filter value back?

vm/devices/net/netvsp/src/saved_state.rs

vm/devices/net/netvsp/src/lib.rs

github-actions · 2025-08-19T01:00:27Z

At least one Petri test failed.

vm/devices/net/netvsp/src/lib.rs

github-actions · 2025-08-19T20:20:40Z

At least one Petri test failed.

vm/devices/net/netvsp/src/lib.rs

vm/devices/net/netvsp/src/rndisprot.rs

vm/devices/net/netvsp/src/lib.rs

…pdates subchannel packet filters.

jstarks · 2025-08-21T23:23:04Z

vm/devices/net/netvsp/src/lib.rs

+                guest_vf_state: guest_vf,
+                filter_state: packet_filter,
+            }));
+        } else if let Some(CoordinatorMessage::Restart) = self.restart {


I guess this would have to be updated, too, to store the new packet filter.

…ate holds filter value.

github-actions · 2025-08-22T01:12:27Z

At least one Petri test failed.

Brian-Perkins · 2025-08-25T20:02:04Z

vm/devices/net/netvsp/src/lib.rs

+                        self.stop_workers().await;
+                        let worker_0_packet_filter =
+                            self.workers[0].state().unwrap().channel.packet_filter;
+                        self.workers.iter_mut().for_each(|worker| {


nit: self.workers.iter_mut().skip(1).for_each(|worker| {

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]>

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. Cherry pick of #1873 Co-authored-by: Sunil Muthuswamy <[email protected]>

benhillis · 2025-08-28T19:12:54Z

Backported to release/2505 in #1927

#1927)" This reverts commit d806090.

#1927)" (#1959) While doing validation of hibernation an issue was found with this patch. This change is being reverted until the follow-up is ready. This reverts commit d806090.

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 drop incoming 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 and #1949 --------- Co-authored-by: erfrimod <[email protected]> Co-authored-by: Sunil Muthuswamy <[email protected]> Co-authored-by: Brian Perkins <[email protected]>

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]>

Copilot AI review requested due to automatic review settings August 15, 2025 22:50

erfrimod requested a review from a team as a code owner August 15, 2025 22:50

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benhillis added backport_2411 Change should be backported to the release/2411 branch backport_2505 Change should be backported to the release/2505 branch labels Aug 15, 2025

jstarks reviewed Aug 16, 2025

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sunilmut and others added 5 commits August 19, 2025 14:40

Handle RNDIS packet filter OID for stopping Rx

4fb8516

New error for unsupported filter. Provide filter value

e602370

save the filter value

94fa5e6

Make savestate optional. Fix test. Have subchannel read from primary.

27cf82e

only modify packet filter when oid is called

61c4cb6

erfrimod force-pushed the erfrimod/netvsp_rndis_packet_filter branch from f6d5eb4 to 61c4cb6 Compare August 19, 2025 21:40

erfrimod added 2 commits August 19, 2025 15:31

adding unit test

7b55d0a

fix clippy error in test

b66c321

jstarks reviewed Aug 20, 2025

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Sending coordinator update message on filter change. restart_queues u…

5343c3e

…pdates subchannel packet filters.

jstarks reviewed Aug 21, 2025

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Remove packet_filter from insert_worker and nic open. Coordinator upd…

2fd20d1

…ate holds filter value.

erfrimod dismissed Brian-Perkins’s stale review via 2fd20d1 August 22, 2025 00:09

Remove obolete comments, space.

fc9260f

erfrimod added 3 commits August 22, 2025 14:59

only send filter update when some

e956194

cleanup. removing redundant filter on primary.

09bcc53

Only update filter if the value is different.

2e331f7

Brian-Perkins reviewed Aug 25, 2025

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Brian-Perkins previously approved these changes Aug 25, 2025

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skip updating channel 0

48c5d97

erfrimod dismissed Brian-Perkins’s stale review via 48c5d97 August 25, 2025 20:17

Brian-Perkins approved these changes Aug 25, 2025

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chris-oo approved these changes Aug 27, 2025

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erfrimod merged commit 6f3ffb3 into microsoft:main Aug 27, 2025
29 checks passed

This was referenced Aug 27, 2025

netvsp: handle RNDIS packet filter OID for stopping Rx #1926

Closed

netvsp: handle RNDIS packet filter OID for stopping Rx (#1873) #1927

Merged

erfrimod mentioned this pull request Aug 27, 2025

netvsp: handle RNDIS packet filter OID for stopping Rx (#1873) #1929

Closed

benhillis added backported_2505 PR that has been backported to release/2505 and removed backport_2505 Change should be backported to the release/2505 branch labels Aug 28, 2025

erfrimod deleted the erfrimod/netvsp_rndis_packet_filter branch September 3, 2025 20:47

benhillis added a commit that referenced this pull request Sep 3, 2025

Revert "netvsp: handle RNDIS packet filter OID for stopping Rx (#1873) (

f3421f1

#1927)" This reverts commit d806090.

Brian-Perkins mentioned this pull request Sep 4, 2025

netvsp: handle RNDIS packet filter OID for stopping Rx #1967

Merged

netvsp: handle RNDIS packet filter OID for stopping Rx #1873

netvsp: handle RNDIS packet filter OID for stopping Rx #1873

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Pull Request Overview

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