Re: [PATCH v1 09/12] net/ice/base: improve global config lock behavior

[Bruce Richardson <bruce.richardson@intel.com>]

On Fri, Sep 05, 2025 at 04:25:19PM -0700, Jacob Keller wrote:
> 
> 
> On 9/5/2025 8:32 AM, Bruce Richardson wrote:
> > On Tue, Sep 02, 2025 at 06:26:59PM +0100, Anatoly Burakov wrote:
> >> From: Jacob Keller <jacob.e.keller@intel.com>
> >>
> >> The ice_cfg_tx_topo function attempts to apply Tx scheduler topology
> >> configuration based on NVM parameters, selecting either a 5 or 9 layer
> >> topology.
> >>
> >> As part of this flow, the driver acquires the "Global Configuration
> >> Lock", which is a hardware resource associated with programming the DDP
> >> package to the device. This "lock" is implemented by firmware as a way to
> >> guarantee that only one PF can program the DDP for a device. Unlike a
> >> traditional lock, once a PF has acquired this lock, no other PF will be
> >> able to acquire it again (including that PF) until a core reset of the
> >> device. Future requests to acquire the lock report that global
> >> configuration has already completed.
> >>
> >> The following flow is used to program the Tx topology:
> >>
> >>  * Read the DDP package for scheduler configuration data
> >>  * Acquire the global configuration lock
> >>  * Program Tx scheduler topology according to DDP package data
> >>  * Trigger a core reset which clears the global configuration lock
> >>
> >> This is followed by the flow for programming the DDP package:
> >>
> >>  * Acquire the global configuration lock (again)
> >>  * Download the DDP package to the device
> >>  * Release the global configuration lock.
> >>
> >> However, if configuration of the Tx topology fails, (i.e.
> >> ice_get_set_tx_topo() returns an error code), the driver exits
> >> ice_cfg_tx_topo() immediately, and fails to trigger core reset.
> >>
> >> While the global configuration lock is held, the firmware rejects most
> >> AdminQ commands, as it is waiting for the DDP package download (or Tx
> >> scheduler topology programming) to occur.
> >>
> >> The current driver flows assume that the global configuration lock has
> >> been reset after programming the Tx topology. Thus, the same PF attempts
> >> to acquire the global lock again, and fails. This results in the driver
> >> reporting "an unknown error occurred when loading the DDP package". It
> >> then attempts to enter safe mode, but ultimately fails to finish
> >> ice_probe() since nearly all AdminQ command report error codes, and the
> >> driver stops loading the device at some point during its initialization.
> >>
> >> We cannot simply release the global lock after a failed call to
> >> ice_get_set_tx_topo(). Releasing the lock indicates to firmware that
> >> global configuration (downloading of the DDP) has completed. Future
> >> attempts by this or other PFs to load the DDP will fail with a report
> >> that the DDP package has already been downloaded. Then, PFs will enter
> >> safe mode as they realize that the package on the device does not meet
> >> the minimum version requirement to load. The reported error messages are
> >> confusing, as they indicate the version of the default "safe mode"
> >> package in the NVM, rather than the version of the DDP package loaded
> >> from the filesystem.
> >>
> >> Instead, we need to trigger core reset to clear global configuration.
> >> This is the lowest level of hardware reset which clears the global
> >> configuration lock and related state. It also clears any already
> >> downloaded DDP. Crucially, it does *not* clear the Tx scheduler topology
> >> configuration.
> >>
> >> Refactor ice_cfg_tx_topo() to always trigger a core reset after acquiring
> >> the global lock, regardless of success or failure of the topology
> >> configuration.
> >>
> >> We need to re-initialize the HW structure when we trigger the core reset.
> >> Previously, this was the responsibility of the core driver to cleanup
> >> after the core reset. Instead, make it the responsibility of this
> >> function. This avoids needless re-initialization for the cases where no
> >> reset occurred.
> >>
> >> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
> >> Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
> >> ---
> >>  drivers/net/intel/ice/base/ice_ddp.c | 34 ++++++++++++++++++----------
> >>  1 file changed, 22 insertions(+), 12 deletions(-)
> >>
> > 
> > Acked-by: Bruce Richardson <bruce.richardson@intel.com>
> > 
> > See one comment inline below.
> > 
> > 
> >> diff --git a/drivers/net/intel/ice/base/ice_ddp.c b/drivers/net/intel/ice/base/ice_ddp.c
> >> index 850c722a3f..68e75be4d2 100644
> >> --- a/drivers/net/intel/ice/base/ice_ddp.c
> >> +++ b/drivers/net/intel/ice/base/ice_ddp.c
> >> @@ -2370,7 +2370,7 @@ int ice_cfg_tx_topo(struct ice_hw *hw, u8 *buf, u32 len)
> >>  	struct ice_buf_hdr *section;
> >>  	struct ice_pkg_hdr *pkg_hdr;
> >>  	enum ice_ddp_state state;
> >> -	u16 i, size = 0, offset;
> >> +	u16 size = 0, offset;
> >>  	u32 reg = 0;
> >>  	int status;
> >>  	u8 flags;
> >> @@ -2457,25 +2457,35 @@ int ice_cfg_tx_topo(struct ice_hw *hw, u8 *buf, u32 len)
> >>  	/* check reset was triggered already or not */
> >>  	reg = rd32(hw, GLGEN_RSTAT);
> >>  	if (reg & GLGEN_RSTAT_DEVSTATE_M) {
> >> -		/* Reset is in progress, re-init the hw again */
> >>  		ice_debug(hw, ICE_DBG_INIT, "Reset is in progress. layer topology might be applied already\n");
> >>  		ice_check_reset(hw);
> >> -		return 0;
> >> +		/* Reset is in progress, re-init the hw again */
> >> +		goto reinit_hw;
> >>  	}
> >>  
> >>  	/* set new topology */
> >>  	status = ice_get_set_tx_topo(hw, new_topo, size, NULL, NULL, true);
> >>  	if (status) {
> >> -		ice_debug(hw, ICE_DBG_INIT, "Set tx topology is failed\n");
> >> -		return status;
> >> +		ice_debug(hw, ICE_DBG_INIT, "Failed setting Tx topology, status %d\n",
> >> +			  status);
> >> +		status = ICE_ERR_CFG;
> >>  	}
> >>  
> >> -	/* new topology is updated, delay 1 second before issuing the CORRER */
> >> -	for (i = 0; i < 10; i++)
> >> -		ice_msec_delay(100, true);
> >> +	/* Even if Tx topology config failed, we need to CORE reset here to
> >> +	 * clear the global configuration lock. Delay 1 second to allow
> >> +	 * hardware to settle then issue a CORER
> >> +	 */
> >> +	ice_msec_delay(1000, true);
> >>  	ice_reset(hw, ICE_RESET_CORER);
> >> -	/* CORER will clear the global lock, so no explicit call
> >> -	 * required for release
> >> -	 */
> >> -	return 0;
> >> +	ice_check_reset(hw);
> >> +
> >> +reinit_hw:
> >> +	/* Since we triggered a CORER, re-initialize hardware */
> >> +	ice_deinit_hw(hw);
> >> +	if (ice_init_hw(hw)) {
> >> +		ice_debug(hw, ICE_DBG_INIT, "Failed to re-init hardware after setting Tx topology\n");
> >> +		return ICE_ERR_RESET_FAILED;
> >> +	}
> >> +
> >> +	return status;
> >>  }
> > 
> > There is a similer deinit + init combo in ice_init_pkg in the same file,
> > which is the only use of this function (in DPDK anyway). Therefore, I
> > believe that that code can be removed now that the reinit is handled by the
> > cfg_tx_topo() function.
> 
> I am not sure we can do that. We program Tx topology by taking the
> global configuration lock, then programming the topology, and then
> performing a CORE reset. We can't simply release the global config lock,
> because then DDP won't be able to download at all. We can't avoid this
> re-init, because after a CORE reset, the drivers AQ setup will be hosed
> and thus we need a re-init.
> 
> ice_init_pkg should be called after Tx topology is executed. If another
> reset occurs there, I think you may still need to do that re-init too.
> There could possibly be a complete refactor that removed the need for a
> double reset, but I am not certain.

Ok, thanks for the analysis and explanation. Taking this patch as-is.

/Bruce