ncdevmem tests that the kernel correctly rejects attempts to deactivate queues with MPs bound.
Make the configure_channels() test support combined channels. Currently it tries to set the queue counts to rx N tx N-1, which only makes sense for devices which have IRQs per ring type. Most modern devices used combined IRQs/channels with both Rx and Tx queues. Since the math is total Rx == combined+Rx setting Rx when combined is non-zero will be increasing the total queue count, not decreasing as the test intends.
Note that the test would previously also try to set the Tx ring count to Rx - 1, for some reason. Which would be 0 if the device has only 2 queues configured.
With this change (device with 2 queues): setting channel count rx:1 tx:1 YNL set channels: Kernel error: 'requested channel counts are too low for existing memory provider setting (2)'
Signed-off-by: Jakub Kicinski kuba@kernel.org --- CC: shuah@kernel.org CC: almasrymina@google.com CC: sdf@fomichev.me CC: joe@dama.to CC: linux-kselftest@vger.kernel.org --- .../selftests/drivers/net/hw/ncdevmem.c | 78 ++++++++++++++++++- 1 file changed, 76 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c index be937542b4c0..71961a7688e6 100644 --- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c +++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c @@ -356,7 +356,81 @@ static int configure_rss(void)
static int configure_channels(unsigned int rx, unsigned int tx) { - return run_command("ethtool -L %s rx %u tx %u", ifname, rx, tx); + struct ethtool_channels_get_req *gchan; + struct ethtool_channels_set_req *schan; + struct ethtool_channels_get_rsp *chan; + struct ynl_error yerr; + struct ynl_sock *ys; + int ret; + + fprintf(stderr, "setting channel count rx:%u tx:%u\n", rx, tx); + + ys = ynl_sock_create(&ynl_ethtool_family, &yerr); + if (!ys) { + fprintf(stderr, "YNL: %s\n", yerr.msg); + return -1; + } + + gchan = ethtool_channels_get_req_alloc(); + if (!gchan) { + ret = -1; + goto exit_close_sock; + } + + ethtool_channels_get_req_set_header_dev_index(gchan, ifindex); + chan = ethtool_channels_get(ys, gchan); + ethtool_channels_get_req_free(gchan); + if (!chan) { + fprintf(stderr, "YNL get channels: %s\n", ys->err.msg); + ret = -1; + goto exit_close_sock; + } + + schan = ethtool_channels_set_req_alloc(); + if (!schan) { + ret = -1; + goto exit_free_chan; + } + + ethtool_channels_set_req_set_header_dev_index(schan, ifindex); + + if (chan->_present.combined_count) { + if (chan->_present.rx_count || chan->_present.tx_count) { + ethtool_channels_set_req_set_rx_count(schan, 0); + ethtool_channels_set_req_set_tx_count(schan, 0); + } + + if (rx == tx) { + ethtool_channels_set_req_set_combined_count(schan, rx); + } else if (rx > tx) { + ethtool_channels_set_req_set_combined_count(schan, tx); + ethtool_channels_set_req_set_rx_count(schan, rx - tx); + } else { + ethtool_channels_set_req_set_combined_count(schan, rx); + ethtool_channels_set_req_set_tx_count(schan, tx - rx); + } + + ret = ethtool_channels_set(ys, schan); + if (ret) + fprintf(stderr, "YNL set channels: %s\n", ys->err.msg); + } else if (chan->_present.rx_count) { + ethtool_channels_set_req_set_rx_count(schan, rx); + ethtool_channels_set_req_set_tx_count(schan, tx); + + ret = ethtool_channels_set(ys, schan); + if (ret) + fprintf(stderr, "YNL set channels: %s\n", ys->err.msg); + } else { + fprintf(stderr, "Error: device has neither combined nor rx channels\n"); + ret = -1; + } + ethtool_channels_set_req_free(schan); +exit_free_chan: + ethtool_channels_get_rsp_free(chan); +exit_close_sock: + ynl_sock_destroy(ys); + + return ret; }
static int configure_flow_steering(struct sockaddr_in6 *server_sin) @@ -752,7 +826,7 @@ void run_devmem_tests(void) error(1, 0, "Failed to bind\n");
/* Deactivating a bound queue should not be legal */ - if (!configure_channels(num_queues, num_queues - 1)) + if (!configure_channels(num_queues, num_queues)) error(1, 0, "Deactivating a bound queue should be illegal.\n");
/* Closing the netlink socket does an implicit unbind */
On Fri, Aug 15, 2025 at 4:15 PM Jakub Kicinski kuba@kernel.org wrote:
ncdevmem tests that the kernel correctly rejects attempts to deactivate queues with MPs bound.
Make the configure_channels() test support combined channels. Currently it tries to set the queue counts to rx N tx N-1, which only makes sense for devices which have IRQs per ring type. Most modern devices used combined IRQs/channels with both Rx and Tx queues. Since the math is total Rx == combined+Rx setting Rx when combined is non-zero will be increasing the total queue count, not decreasing as the test intends.
Note that the test would previously also try to set the Tx ring count to Rx - 1, for some reason. Which would be 0 if the device has only 2 queues configured.
Yes, I think that was a mistake. I can't think of any reason we'd really want to do that.
With this change (device with 2 queues): setting channel count rx:1 tx:1 YNL set channels: Kernel error: 'requested channel counts are too low for existing memory provider setting (2)'
Signed-off-by: Jakub Kicinski kuba@kernel.org
Reviewed-by: Mina Almasry almasrymina@google.com
-- Thanks, Mina
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