On 7/8/22 11:23, Maxime Coquelin wrote:


On 7/6/22 11:24, abhimanyu.sa...@xilinx.com wrote:
From: Abhimanyu Saini <absa...@amd.com>

libvhost calls dev_conf() before prosessing the
VHOST_USER_SET_VRING_CALL message for the last VQ. So
this message is processed after dev_conf() returns.

However, the dev_conf() function spawns a thread to set
rte_vhost_host_notifier_ctrl() before returning control to
libvhost. This parallel thread in turn invokes get_notify_area().
To get the notify_area, the vdpa driver needs to query the HW and
for this query it needs an enabled VQ.

But at the same time libvhost is processing the last
VHOST_USER_SET_VRING_CALL, and to do that it disables the last VQ.

Hence there is a race b/w the libvhost and the vdpa driver.

To resolve this race condition, query the HW and cache notify_area
inside dev_conf() instead of doing it the parallel thread.

Signed-off-by: Abhimanyu Saini <absa...@amd.com>
---
  drivers/vdpa/sfc/sfc_vdpa_ops.c | 36 ++++++++++++++++++------------------
  drivers/vdpa/sfc/sfc_vdpa_ops.h |  1 +
  2 files changed, 19 insertions(+), 18 deletions(-)


Applied to dpdk-next-virtio/main.

Sorry, I notice it is missing the Fixes tag, and cc'ing stable.
Can you confirm this is needed and provide the faulty commit?

Thanks,
Maxime

Thanks,
Maxime

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