| Message ID | 20241001163200.1802522-1-nnac123@linux.ibm.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | ibmvnic: Fix for send scrq direct | expand |
Hello: This patch was applied to netdev/net.git (main) by Jakub Kicinski <kuba@kernel.org>: On Tue, 1 Oct 2024 11:31:59 -0500 you wrote: > This is a v2 of a patchset (now just patch) which addresses a > bug in a new feature which is causing major link UP issues with > certain physical cards. > > For a full summary of the issue: > 1. During vnic initialization we get the following values from vnic > server regarding "Transmit / Receive Descriptor Requirement" (see > PAPR Table 584. CAPABILITIES Commands): > - LSO Tx frame = 0x0F , header offsets + L2, L3, L4 headers required > - CSO Tx frame = 0x0C , header offsets + L2 header required > - standard frame = 0x0C , header offsets + L2 header required > 2. Assume we are dealing with only "standard frames" from now on (no > CSO, no LSO) > 3. When using 100G backing device, we don't hand vnic server any header > information and TX is successful > 4. When using 25G backing device, we don't hand vnic server any header > information and TX fails and we get "Adapter Error" transport events. > The obvious issue here is that vnic client should be respecting the 0X0C > header requirement for standard frames. But 100G cards will also give > 0x0C despite the fact that we know TX works if we ignore it. That being > said, we still must respect values given from the managing server. Will > need to work with them going forward to hopefully get 100G cards to > return 0x00 for this bitstring so the performance gains of using > send_subcrq_direct can be continued. > > [...] Here is the summary with links: - [net,v2,1/1] ibmvnic: Inspect header requirements before using scrq direct https://git.kernel.org/netdev/net/c/de390657b5d6 You are awesome, thank you!
This is a v2 of a patchset (now just patch) which addresses a bug in a new feature which is causing major link UP issues with certain physical cards. For a full summary of the issue: 1. During vnic initialization we get the following values from vnic server regarding "Transmit / Receive Descriptor Requirement" (see PAPR Table 584. CAPABILITIES Commands): - LSO Tx frame = 0x0F , header offsets + L2, L3, L4 headers required - CSO Tx frame = 0x0C , header offsets + L2 header required - standard frame = 0x0C , header offsets + L2 header required 2. Assume we are dealing with only "standard frames" from now on (no CSO, no LSO) 3. When using 100G backing device, we don't hand vnic server any header information and TX is successful 4. When using 25G backing device, we don't hand vnic server any header information and TX fails and we get "Adapter Error" transport events. The obvious issue here is that vnic client should be respecting the 0X0C header requirement for standard frames. But 100G cards will also give 0x0C despite the fact that we know TX works if we ignore it. That being said, we still must respect values given from the managing server. Will need to work with them going forward to hopefully get 100G cards to return 0x00 for this bitstring so the performance gains of using send_subcrq_direct can be continued. Thanks Simon for review on v1 [1]. Much appreciated. Changes in v2: - drop the statistics tracking patch (send to net-next) - Fix formatting and commit of Fixes tag Nick Child (1): ibmvnic: Inspect header requirements before using scrq direct drivers/net/ethernet/ibm/ibmvnic.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)