RE: [EXT] Re: [net PATCH 1/7] octeontx2-af: Secure APR table update with the lock

[Geethasowjanya Akula]

>-----Original Message-----
>From: Leon Romanovsky <leon@xxxxxxxxxx> 
>Sent: Thursday, March 30, 2023 11:26 AM
>To: Sai Krishna Gajula <saikrishnag@xxxxxxxxxxx>
>Cc: davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx; pabeni@xxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Sunil Kovvuri Goutham <sgoutham@xxxxxxxxxxx>; >richardcochran@xxxxxxxxx; Geethasowjanya Akula <gakula@xxxxxxxxxxx>
>Subject: [EXT] Re: [net PATCH 1/7] octeontx2-af: Secure APR table update with the lock

>External Email

>----------------------------------------------------------------------
>On Wed, Mar 29, 2023 at 10:36:13PM +0530, Sai Krishna wrote:
>> From: Geetha sowjanya <gakula@xxxxxxxxxxx>
>> 
>> APR table contains the lmtst base address of PF/VFs.
>> These entries are updated by the PF/VF during the device probe. Due to 
>> race condition while updating the entries are getting corrupted. Hence 
>> secure the APR table update with the lock.

>However, I don't see rsrc_lock in probe path.
>otx2_probe()
>-> cn10k_lmtst_init()
> -> lmt_base/lmstst is updated with and without mbox.lock.

>Where did you take rsrc_lock in probe flow?

rsrc_lock is initialized in AF driver. PF/VF driver in cn10k_lmtst_init() send a mbox request to AF to update the lmtst table. 
mbox handler in AF takes rsrc_lock to update lmtst table.

Thanks,
Geetha.

>Thanks

>> 
>> Fixes: 893ae97214c3 ("octeontx2-af: cn10k: Support configurable LMTST 
>> regions")
>> Signed-off-by: Geetha sowjanya <gakula@xxxxxxxxxxx>
>> Signed-off-by: Sunil Kovvuri Goutham <sgoutham@xxxxxxxxxxx>
>> Signed-off-by: Sai Krishna <saikrishnag@xxxxxxxxxxx>
>> ---
>>  drivers/net/ethernet/marvell/octeontx2/af/rvu_cn10k.c | 8 +++++---
>>  1 file changed, 5 insertions(+), 3 deletions(-)
>> 
>> diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_cn10k.c 
>> b/drivers/net/ethernet/marvell/octeontx2/af/rvu_cn10k.c
>> index 4ad9ff025c96..8530250f6fba 100644
>> --- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_cn10k.c
>> +++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_cn10k.c
>> @@ -142,16 +142,17 @@ int rvu_mbox_handler_lmtst_tbl_setup(struct rvu *rvu,
>>  	 * region, if so, convert that IOVA to physical address and
>>  	 * populate LMT table with that address
>>  	 */
>> +	mutex_lock(&rvu->rsrc_lock);
>>  	if (req->use_local_lmt_region) {
>>  		err = rvu_get_lmtaddr(rvu, req->hdr.pcifunc,
>>  				      req->lmt_iova, &lmt_addr);
>>  		if (err < 0)
>> -			return err;
>> +			goto error;
>>  
>>  		/* Update the lmt addr for this PFFUNC in the LMT table */
>>  		err = rvu_update_lmtaddr(rvu, req->hdr.pcifunc, lmt_addr);
>>  		if (err)
>> -			return err;
>> +			goto error;
>>  	}
>>  
>>  	/* Reconfiguring lmtst map table in lmt region shared mode i.e. make 
>> @@ -181,7 +182,7 @@ int rvu_mbox_handler_lmtst_tbl_setup(struct rvu *rvu,
>>  		 */
>>  		err = rvu_update_lmtaddr(rvu, req->hdr.pcifunc, val);
>>  		if (err)
>> -			return err;
>> +			goto error;
>>  	}
>>  
>>  	/* This mailbox can also be used to update word1 of 
>> APR_LMT_MAP_ENTRY_S @@ -230,6 +231,7 @@ int rvu_mbox_handler_lmtst_tbl_setup(struct rvu *rvu,
>>  	}
>>  
>>  error:
>> +	mutex_unlock(&rvu->rsrc_lock);
>>  	return err;
>>  }
>>  
>> --
>> 2.25.1
>>