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

Sai Krishna posted 7 patches 2 years, 10 months ago
There is a newer version of this series
[net PATCH 1/7] octeontx2-af: Secure APR table update with the lock
Posted by Sai Krishna 2 years, 10 months ago 
From: Geetha sowjanya <gakula@marvell.com>

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.

Fixes: 893ae97214c3 ("octeontx2-af: cn10k: Support configurable LMTST regions")
Signed-off-by: Geetha sowjanya <gakula@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: Sai Krishna <saikrishnag@marvell.com>
---
 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
Re: [net PATCH 1/7] octeontx2-af: Secure APR table update with the lock
Posted by Leon Romanovsky 2 years, 10 months ago 
On Wed, Mar 29, 2023 at 10:36:13PM +0530, Sai Krishna wrote:
> From: Geetha sowjanya <gakula@marvell.com>
> 
> 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?

Thanks

> 
> Fixes: 893ae97214c3 ("octeontx2-af: cn10k: Support configurable LMTST regions")
> Signed-off-by: Geetha sowjanya <gakula@marvell.com>
> Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
> Signed-off-by: Sai Krishna <saikrishnag@marvell.com>
> ---
>  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
>
RE: [EXT] Re: [net PATCH 1/7] octeontx2-af: Secure APR table update with the lock
Posted by Geethasowjanya Akula 2 years, 10 months ago 
>-----Original Message-----
>From: Leon Romanovsky <leon@kernel.org> 
>Sent: Thursday, March 30, 2023 11:26 AM
>To: Sai Krishna Gajula <saikrishnag@marvell.com>
>Cc: davem@davemloft.net; edumazet@google.com; kuba@kernel.org; pabeni@redhat.com; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Sunil Kovvuri Goutham <sgoutham@marvell.com>; >richardcochran@gmail.com; Geethasowjanya Akula <gakula@marvell.com>
>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@marvell.com>
>> 
>> 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@marvell.com>
>> Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
>> Signed-off-by: Sai Krishna <saikrishnag@marvell.com>
>> ---
>>  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
>>
Re: [EXT] Re: [net PATCH 1/7] octeontx2-af: Secure APR table update with the lock
Posted by Leon Romanovsky 2 years, 10 months ago 
On Thu, Mar 30, 2023 at 06:56:54AM +0000, Geethasowjanya Akula wrote:
> 
> >-----Original Message-----
> >From: Leon Romanovsky <leon@kernel.org> 
> >Sent: Thursday, March 30, 2023 11:26 AM
> >To: Sai Krishna Gajula <saikrishnag@marvell.com>
> >Cc: davem@davemloft.net; edumazet@google.com; kuba@kernel.org; pabeni@redhat.com; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Sunil Kovvuri Goutham <sgoutham@marvell.com>; >richardcochran@gmail.com; Geethasowjanya Akula <gakula@marvell.com>
> >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@marvell.com>
> >> 
> >> 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.

Can you please present the stack trace of such flow? What are the actual variables/struct rsrc_lock
is protecting?

Thanks

> 
> Thanks,
> Geetha.
> 
> >Thanks
> 
> >> 
> >> Fixes: 893ae97214c3 ("octeontx2-af: cn10k: Support configurable LMTST 
> >> regions")
> >> Signed-off-by: Geetha sowjanya <gakula@marvell.com>
> >> Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
> >> Signed-off-by: Sai Krishna <saikrishnag@marvell.com>
> >> ---
> >>  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
> >>
RE: [EXT] Re: [net PATCH 1/7] octeontx2-af: Secure APR table update with the lock
Posted by Geethasowjanya Akula 2 years, 10 months ago 

>-----Original Message-----
>From: Leon Romanovsky <leon@kernel.org> 
>Sent: Thursday, March 30, 2023 12:46 PM
>To: Geethasowjanya Akula <gakula@marvell.com>
>Cc: Sai Krishna Gajula <saikrishnag@marvell.com>; davem@davemloft.net; edumazet@google.com; kuba@kernel.org; pabeni@redhat.com; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Sunil >Kovvuri Goutham <sgoutham@marvell.com>; richardcochran@gmail.com
>Subject: Re: [EXT] Re: [net PATCH 1/7] octeontx2-af: Secure APR table update with the lock
>
>On Thu, Mar 30, 2023 at 06:56:54AM +0000, Geethasowjanya Akula wrote:
>> 
>> >-----Original Message-----
>> >From: Leon Romanovsky <leon@kernel.org>
>> >Sent: Thursday, March 30, 2023 11:26 AM
>> >To: Sai Krishna Gajula <saikrishnag@marvell.com>
>> >Cc: davem@davemloft.net; edumazet@google.com; kuba@kernel.org; 
>> >pabeni@redhat.com; netdev@vger.kernel.org; 
>> >linux-kernel@vger.kernel.org; Sunil Kovvuri Goutham 
>> ><sgoutham@marvell.com>; >richardcochran@gmail.com; Geethasowjanya 
>> >Akula <gakula@marvell.com>
>> >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@marvell.com>
>> >> 
>> >> 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.

>Can you please present the stack trace of such flow? What are the actual variables/struct rsrc_lock is protecting?

The lock tries to protect the request and response register at line#73 and line#83 in below function, from getting overwritten when
Multiple PFs invokes rvu_get_lmtaddr() simultaneously. 
For example, if PF1 submit the request at line#73 and got permitted before it reads the response at line#80.
PF2 got scheduled submit the request then the response of PF1 is overwritten by the PF2 response.  
When PF1 gets reschedule, it reads wrong data.

#static int rvu_get_lmtaddr(struct rvu *rvu, u16 pcifunc,
  59                            u64 iova, u64 *lmt_addr)
  60 {
  61        [...]
  68 
  69         rvu_write64(rvu, BLKADDR_RVUM, RVU_AF_SMMU_ADDR_REQ, iova);
  70         pf = rvu_get_pf(pcifunc) & 0x1F;
  71         val = BIT_ULL(63) | BIT_ULL(14) | BIT_ULL(13) | pf << 8 |
  72               ((pcifunc & RVU_PFVF_FUNC_MASK) & 0xFF);
  73         rvu_write64(rvu, BLKADDR_RVUM, RVU_AF_SMMU_TXN_REQ, val);
  74 
  75         err = rvu_poll_reg(rvu, BLKADDR_RVUM, RVU_AF_SMMU_ADDR_RSP_STS, BIT_ULL(0), false);
  76         if (err) {
  77                 dev_err(rvu->dev, "%s LMTLINE iova transulation failed\n", __func__);
  78                 return err;
  79         }
  80         val = rvu_read64(rvu, BLKADDR_RVUM, RVU_AF_SMMU_ADDR_RSP_STS);
  81         if (val & ~0x1ULL) {
  82                 dev_err(rvu->dev, "%s LMTLINE iova transulation failed err:%llx\n", __func__, val);
  83                 return -EIO;
  84         }
  85         
  
Thanks.
>>Thanks

>> 
>> Thanks,
>> Geetha.
>> 
>> >Thanks
>> 
>> >> 
>> >> Fixes: 893ae97214c3 ("octeontx2-af: cn10k: Support configurable 
>> >> LMTST
>> >> regions")
>> >> Signed-off-by: Geetha sowjanya <gakula@marvell.com>
>> >> Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
>> >> Signed-off-by: Sai Krishna <saikrishnag@marvell.com>
>> >> ---
>> >>  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
>> >>
Re: [EXT] Re: [net PATCH 1/7] octeontx2-af: Secure APR table update with the lock
Posted by Leon Romanovsky 2 years, 10 months ago 
On Fri, Mar 31, 2023 at 08:56:59AM +0000, Geethasowjanya Akula wrote:
> 
> 
> >-----Original Message-----
> >From: Leon Romanovsky <leon@kernel.org> 
> >Sent: Thursday, March 30, 2023 12:46 PM
> >To: Geethasowjanya Akula <gakula@marvell.com>
> >Cc: Sai Krishna Gajula <saikrishnag@marvell.com>; davem@davemloft.net; edumazet@google.com; kuba@kernel.org; pabeni@redhat.com; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Sunil >Kovvuri Goutham <sgoutham@marvell.com>; richardcochran@gmail.com
> >Subject: Re: [EXT] Re: [net PATCH 1/7] octeontx2-af: Secure APR table update with the lock
> >
> >On Thu, Mar 30, 2023 at 06:56:54AM +0000, Geethasowjanya Akula wrote:
> >> 
> >> >-----Original Message-----
> >> >From: Leon Romanovsky <leon@kernel.org>
> >> >Sent: Thursday, March 30, 2023 11:26 AM
> >> >To: Sai Krishna Gajula <saikrishnag@marvell.com>
> >> >Cc: davem@davemloft.net; edumazet@google.com; kuba@kernel.org; 
> >> >pabeni@redhat.com; netdev@vger.kernel.org; 
> >> >linux-kernel@vger.kernel.org; Sunil Kovvuri Goutham 
> >> ><sgoutham@marvell.com>; >richardcochran@gmail.com; Geethasowjanya 
> >> >Akula <gakula@marvell.com>
> >> >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@marvell.com>
> >> >> 
> >> >> 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.
> 
> >Can you please present the stack trace of such flow? What are the actual variables/struct rsrc_lock is protecting?
> 
> The lock tries to protect the request and response register at line#73 and line#83 in below function, from getting overwritten when
> Multiple PFs invokes rvu_get_lmtaddr() simultaneously. 
> For example, if PF1 submit the request at line#73 and got permitted before it reads the response at line#80.
> PF2 got scheduled submit the request then the response of PF1 is overwritten by the PF2 response.  
> When PF1 gets reschedule, it reads wrong data.

I see, thanks

Patchew 2.1-devel-b67e4c2

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