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enic: wire V2 SR-IOV enable with admin channel and MBOX

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Extend enic_sriov_configure() to handle V2 SR-IOV VFs. When the PF
detects V2 VF device IDs, the enable path allocates per-VF MBOX state,
initializes the MBOX protocol, opens the admin channel, and then calls
pci_enable_sriov(). The admin channel must be ready before VFs are
created so that VF drivers can immediately begin the MBOX capability
and registration handshake during their probe.

The enic_sriov_configure() dispatcher and its V2 helpers
(enic_sriov_v2_enable, enic_sriov_v2_disable) are defined here but
intentionally not yet wired into struct pci_driver via
.sriov_configure -- hence the __maybe_unused annotations.  This
series introduces only the admin channel and MBOX infrastructure;
sysfs-driven V2 enable/disable will be activated in a follow-up
patch by adding ".sriov_configure = enic_sriov_configure," to
enic_driver.

Because .sriov_configure is not registered yet, enic_sriov_configure()
cannot run concurrently with the rtnl-protected reset paths
(enic_reset(), enic_tx_hang_reset()) in this series, so there is no
reachable locking race between SR-IOV enable/disable and reset.  The
follow-up patch that wires the callback will add the necessary
serialization against those paths.  Note that simply taking rtnl_lock()
around the enable path is not viable, because pci_enable_sriov()
triggers VF probe and register_netdev(), which themselves acquire rtnl;
the wiring patch therefore uses finer-grained serialization.

The disable path first clears ENIC_SRIOV_ENABLED and flushes the
link-notify work, so no further VF link-state broadcast can run, then
calls pci_disable_sriov() (VF drivers unregister via MBOX), closes the
admin channel, and frees per-VF state.  Clearing the flag and flushing
the work before vf_state is freed closes a use-after-free window
against the link-notify path.

Notify registered VFs of PF link transitions: enic_link_check()
schedules link_notify_work on each carrier up/down edge, and the work
handler sends PF_LINK_STATE_NOTIF to the VFs from process context.
The broadcast cannot run directly in enic_link_check() because the
MBOX send path may sleep and link check runs in the notify timer/ISR
context.

On a V2 VF the admin-channel (PF) link-state notification is the sole
authority for carrier state, so enic_link_check() returns early for
such VFs.  As a side effect the VF retains the firmware-provided static
Rx interrupt coalescing (config.intr_timer_usec) rather than PF-driven
speed-adaptive coalescing; this is intentional, as adaptive Rx
coalescing is a PF-only responsibility for V2 VFs.

Re-establish the admin/MBOX channel across a PF reset.  enic_reset()
and enic_tx_hang_reset() fully close the admin channel before the
soft/hang reset (which wipes all hardware queues, including the admin
WQ/RQ), then reopen it and re-run enic_mbox_init() after the data path
is back up, and re-push the current link state to registered VFs.

Reject VF port profile requests when V2 SR-IOV is active
(enic_is_valid_pp_vf), since enic->pp is not reallocated for V2 VFs
and the V2 protocol uses MBOX instead of port profiles.

Update enic_remove() to run enic_dev_deinit() and vnic_dev_close()
after SR-IOV teardown, so the PF device remains functional while VFs
are being cleaned up.  This ordering applies to both V1 and V2 SR-IOV
paths.

Restrict the probe-time SR-IOV auto-enable to the legacy VF types (V1
and usNIC).  A V2-capable adapter whose firmware lacks V2 support is
downgraded to ENIC_VF_TYPE_NONE, and V2 VFs require the admin channel
which is only brought up via sysfs enic_sriov_configure(); neither
must be auto-enabled through the legacy pci_enable_sriov() path at
probe.

Signed-off-by: Satish Kharat <satishkh@cisco.com>
Link: https://patch.msgid.link/20260812-enic-sriov-v2-admin-channel-v2-v13-9-b3809e448aba@cisco.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Satish Kharat 2026-08-12 05:48:09 -07:00 • committed by Jakub Kicinski
commit 4ff204cef0
7 changed files with 301 additions and 16 deletions
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