gve: set xdp redirect target only when it is available

commit 415cadd505464d9a11ff5e0f6e0329c127849da5 upstream.

Before this patch the NETDEV_XDP_ACT_NDO_XMIT XDP feature flag is set by
default as

gve: set xdp redirect target only when it is available

commit 415cadd505464d9a11ff5e0f6e0329c127849da5 upstream.

Before this patch the NETDEV_XDP_ACT_NDO_XMIT XDP feature flag is set by
default as part of driver initialization, and is never cleared. However,
this flag differs from others in that it is used as an indicator for
whether the driver is ready to perform the ndo_xdp_xmit operation as
part of an XDP_REDIRECT. Kernel helpers
xdp_features_(set|clear)_redirect_target exist to convey this meaning.

This patch ensures that the netdev is only reported as a redirect target
when XDP queues exist to forward traffic.

Fixes: 39a7f4aa3e4a ("gve: Add XDP REDIRECT support for GQI-QPL format")
Cc: stable@vger.kernel.org
Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Jeroen de Borst <jeroendb@google.com>
Signed-off-by: Joshua Washington <joshwash@google.com>
Link: https://patch.msgid.link/20250214224417.1237818-1-joshwash@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Joshua Washington <joshwash@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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eth: gve: use appropriate helper to set xdp_features

[ Upstream commit db78475ba0d3c66d430f7ded2388cc041078a542 ]

Commit f85949f98206 ("xdp: add xdp_set_features_flag utility routine")
added routin

eth: gve: use appropriate helper to set xdp_features

[ Upstream commit db78475ba0d3c66d430f7ded2388cc041078a542 ]

Commit f85949f98206 ("xdp: add xdp_set_features_flag utility routine")
added routines to inform the core about XDP flag changes.
GVE support was added around the same time and missed using them.

GVE only changes the flags on error recover or resume.
Presumably the flags may change during resume if VM migrated.
User would not get the notification and upper devices would
not get a chance to recalculate their flags.

Fixes: 75eaae158b1b ("gve: Add XDP DROP and TX support for GQI-QPL format")
Reviewed-By: Jeroen de Borst <jeroendb@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250106180210.1861784-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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gve: guard XDP xmit NDO on existence of xdp queues

commit ff7c2dea9dd1a436fc79d6273adffdcc4a7ffea3 upstream.

In GVE, dedicated XDP queues only exist when an XDP program is installed
and the interfa

gve: guard XDP xmit NDO on existence of xdp queues

commit ff7c2dea9dd1a436fc79d6273adffdcc4a7ffea3 upstream.

In GVE, dedicated XDP queues only exist when an XDP program is installed
and the interface is up. As such, the NDO XDP XMIT callback should
return early if either of these conditions are false.

In the case of no loaded XDP program, priv->num_xdp_queues=0 which can
cause a divide-by-zero error, and in the case of interface down,
num_xdp_queues remains untouched to persist XDP queue count for the next
interface up, but the TX pointer itself would be NULL.

The XDP xmit callback also needs to synchronize with a device
transitioning from open to close. This synchronization will happen via
the GVE_PRIV_FLAGS_NAPI_ENABLED bit along with a synchronize_net() call,
which waits for any RCU critical sections at call-time to complete.

Fixes: 39a7f4aa3e4a ("gve: Add XDP REDIRECT support for GQI-QPL format")
Cc: stable@vger.kernel.org
Signed-off-by: Joshua Washington <joshwash@google.com>
Signed-off-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Shailend Chand <shailend@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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gve: guard XSK operations on the existence of queues

commit 40338d7987d810fcaa95c500b1068a52b08eec9b upstream.

This patch predicates the enabling and disabling of XSK pools on the
existence of queu

gve: guard XSK operations on the existence of queues

commit 40338d7987d810fcaa95c500b1068a52b08eec9b upstream.

This patch predicates the enabling and disabling of XSK pools on the
existence of queues. As it stands, if the interface is down, disabling
or enabling XSK pools would result in a crash, as the RX queue pointer
would be NULL. XSK pool registration will occur as part of the next
interface up.

Similarly, xsk_wakeup needs be guarded against queues disappearing
while the function is executing, so a check against the
GVE_PRIV_FLAGS_NAPI_ENABLED flag is added to synchronize with the
disabling of the bit and the synchronize_net() in gve_turndown.

Fixes: fd8e40321a12 ("gve: Add AF_XDP zero-copy support for GQI-QPL format")
Cc: stable@vger.kernel.org
Signed-off-by: Joshua Washington <joshwash@google.com>
Signed-off-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Shailend Chand <shailend@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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