On Thu, Mar 9, 2023 at 1:38 PM David Marchand <david.march...@redhat.com> wrote:
>
> In the situation when a port was started while no virtio driver was
> connected, Rx interrupts were broken.
> They were also broken after a virtio driver reconnects.
>
> There were several issues mixed in:
> - this driver was not exposing a fixed file descriptor per Rx queue,
> If a virtio driver was not connected yet, each Rx queue vector was
> pointing at a -1 fd, and an application could interpret this as a lack
> of Rx interrupt support,
> - when a virtio driver later (re)connected, this net/vhost driver was
> hacking into the EAL layer epoll fd to remove a old vring kickfd and
> insert the new vring kickfd. This hack constitutes a layer violation
> plus users of rte_eth_dev_rx_intr_ctl_q_get_fd() were not notified of
> this change,
> - in the case of reconnection, because the interrupt handle was
> reallocated, a 0 fd was failing to be removed from the EAL layer
> epoll fd, which resulted in never fixing the EAL epoll fd,
>
> To fix Rx interrupts:
> - allocating (eth_vhost_install_intr) / releasing
> (eth_vhost_uninstall_intr) the interrupt handle is moved when
> starting / closing the port, while setting / resetting per rxq fd is
> triggered by vhost events via some new helpers (see
> eth_vhost_configure_intr and eth_vhost_unconfigure_intr),
> - a "proxy" epoll fd is created per Rx queue at the time the interrupt
> handle is allocated, so applications can start waiting for events on
> those fds, even before a virtio driver initialises,
> - when available, vring kickd are populated in the "proxy" epoll fd,
>
Maxime, Chenbo,
Dukai confirms this series fix it, we can mark this patch as fixing:
Bugzilla ID: 1135
Do you want me to respin a series or can you fix when applying?
> Fixes: 3f8ff12821e4 ("vhost: support interrupt mode")
> Fixes: 3d4cd4be577c ("net/vhost: fix interrupt mode")
> Fixes: d61138d4f0e2 ("drivers: remove direct access to interrupt handle")
> Cc: sta...@dpdk.org
>
> Signed-off-by: David Marchand <david.march...@redhat.com>
Thanks.
--
David Marchand
