[PATCH v3 0/1] cxl/pmem: debug invalid serial number data

[PATCH v3 0/1] cxl/pmem: debug invalid serial number data

[Yuquan Wang]

Background
==========
A device with missing or invalid serial number is not compliant with the
spec. But we could still use it to create a nvdimm pmem region and set a
non-zero cookie of nd_interleave_set, for example:
  1. create a cxl pmem region interleaved with 2 devices (one with
     serial number 0 and the other with serial number 1), and the cookie
     would be non-zero/valid.
  2. create the second cxl pmem region by 1 device with no serial number
     and this region would have a non-zero cookie because the offset of
     dpa is non-zero.

Problem
=======
In a nvdimm interleave-set each device with an invalid or zero
serial number may cause pmem region initialization to fail, but in
cxl case such device could still set cookies of nd_interleave_set
and create a nvdimm pmem region.

CXL Pmem Validation
===================
This patch adds the validation of serial number in cxl pmem region creation.
The event of no serial number would cause to fail to set the cookie
and pmem region.

cxl-test
========
A mock serial number is set from the platform device id and 0 is a valid
platform device id. For cxl-test to work properly, always +1 on mock
device's serial number.
Yuquan Wang (1):
  cxl/pmem: debug invalid serial number data

 drivers/cxl/pmem.c           | 8 ++++++++
 tools/testing/cxl/test/mem.c | 2 +-
 2 files changed, 9 insertions(+), 1 deletion(-)

-- 
2.34.1

[PATCH v3 1/1] cxl/pmem: debug invalid serial number data

[Yuquan Wang]

In a nvdimm interleave-set each device with an invalid or zero
serial number may cause pmem region initialization to fail, but in
cxl case such device could still set cookies of nd_interleave_set
and create a nvdimm pmem region.

This adds the validation of serial number in cxl pmem region creation.
The event of no serial number would cause to fail to set the cookie
and pmem region.

For cxl-test to work properly, always +1 on mock device's serial
number.

Signed-off-by: Yuquan Wang <wangyuquan1236@phytium.com.cn>
---
 drivers/cxl/pmem.c           | 8 ++++++++
 tools/testing/cxl/test/mem.c | 2 +-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c
index f9c95996e937..73787afe1b9d 100644
--- a/drivers/cxl/pmem.c
+++ b/drivers/cxl/pmem.c
@@ -383,6 +383,14 @@ static int cxl_pmem_region_probe(struct device *dev)
 			.position = i,
 		};
 		info[i].offset = m->start;
+
+		if (cxlds->serial == 0) {
+			/* include missing alongside invalid in this error message. */
+			dev_err(dev, "%s: invalid or missing serial number\n",
+				dev_name(&cxlmd->dev));
+			rc = -ENXIO;
+			goto out_nvd;
+		}
 		info[i].serial = cxlds->serial;
 	}
 	ndr_desc.num_mappings = cxlr_pmem->nr_mappings;
diff --git a/tools/testing/cxl/test/mem.c b/tools/testing/cxl/test/mem.c
index 8d731bd63988..9e098cf06603 100644
--- a/tools/testing/cxl/test/mem.c
+++ b/tools/testing/cxl/test/mem.c
@@ -1533,7 +1533,7 @@ static int cxl_mock_mem_probe(struct platform_device *pdev)
 	mds->event.buf = (struct cxl_get_event_payload *) mdata->event_buf;
 	INIT_DELAYED_WORK(&mds->security.poll_dwork, cxl_mockmem_sanitize_work);
 
-	cxlds->serial = pdev->id;
+	cxlds->serial = pdev->id + 1;
 	if (is_rcd(pdev))
 		cxlds->rcd = true;
 
-- 
2.34.1

Re: [PATCH v3 1/1] cxl/pmem: debug invalid serial number data

[Fan Ni]

On Tue, Feb 18, 2025 at 09:47:46AM +0800, Yuquan Wang wrote:
> In a nvdimm interleave-set each device with an invalid or zero
> serial number may cause pmem region initialization to fail, but in
> cxl case such device could still set cookies of nd_interleave_set
> and create a nvdimm pmem region.
> 
> This adds the validation of serial number in cxl pmem region creation.
> The event of no serial number would cause to fail to set the cookie
> and pmem region.
> 
> For cxl-test to work properly, always +1 on mock device's serial
> number.
> 
> Signed-off-by: Yuquan Wang <wangyuquan1236@phytium.com.cn>
> ---
>  drivers/cxl/pmem.c           | 8 ++++++++
>  tools/testing/cxl/test/mem.c | 2 +-
>  2 files changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c
> index f9c95996e937..73787afe1b9d 100644
> --- a/drivers/cxl/pmem.c
> +++ b/drivers/cxl/pmem.c
> @@ -383,6 +383,14 @@ static int cxl_pmem_region_probe(struct device *dev)
>  			.position = i,
>  		};
>  		info[i].offset = m->start;
> +
> +		if (cxlds->serial == 0) {
> +			/* include missing alongside invalid in this error message. */
> +			dev_err(dev, "%s: invalid or missing serial number\n",
> +				dev_name(&cxlmd->dev));
> +			rc = -ENXIO;
> +			goto out_nvd;
> +		}

Should we do the check earlier in the code? 
For example, right below if (!nvdimm) {}

Fan

>  		info[i].serial = cxlds->serial;
>  	}
>  	ndr_desc.num_mappings = cxlr_pmem->nr_mappings;
> diff --git a/tools/testing/cxl/test/mem.c b/tools/testing/cxl/test/mem.c
> index 8d731bd63988..9e098cf06603 100644
> --- a/tools/testing/cxl/test/mem.c
> +++ b/tools/testing/cxl/test/mem.c
> @@ -1533,7 +1533,7 @@ static int cxl_mock_mem_probe(struct platform_device *pdev)
>  	mds->event.buf = (struct cxl_get_event_payload *) mdata->event_buf;
>  	INIT_DELAYED_WORK(&mds->security.poll_dwork, cxl_mockmem_sanitize_work);
>  
> -	cxlds->serial = pdev->id;
> +	cxlds->serial = pdev->id + 1;
>  	if (is_rcd(pdev))
>  		cxlds->rcd = true;
>  
> -- 
> 2.34.1
> 

Re: [PATCH v3 1/1] cxl/pmem: debug invalid serial number data

[Yuquan Wang]

On Mon, Feb 17, 2025 at 06:20:18PM -0800, Fan Ni wrote:
> On Tue, Feb 18, 2025 at 09:47:46AM +0800, Yuquan Wang wrote:
> > In a nvdimm interleave-set each device with an invalid or zero
> > serial number may cause pmem region initialization to fail, but in
> > cxl case such device could still set cookies of nd_interleave_set
> > and create a nvdimm pmem region.
> > 
> > This adds the validation of serial number in cxl pmem region creation.
> > The event of no serial number would cause to fail to set the cookie
> > and pmem region.
> > 
> > For cxl-test to work properly, always +1 on mock device's serial
> > number.
> > 
> > Signed-off-by: Yuquan Wang <wangyuquan1236@phytium.com.cn>
> > ---
> >  drivers/cxl/pmem.c           | 8 ++++++++
> >  tools/testing/cxl/test/mem.c | 2 +-
> >  2 files changed, 9 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c
> > index f9c95996e937..73787afe1b9d 100644
> > --- a/drivers/cxl/pmem.c
> > +++ b/drivers/cxl/pmem.c
> > @@ -383,6 +383,14 @@ static int cxl_pmem_region_probe(struct device *dev)
> >  			.position = i,
> >  		};
> >  		info[i].offset = m->start;
> > +
> > +		if (cxlds->serial == 0) {
> > +			/* include missing alongside invalid in this error message. */
> > +			dev_err(dev, "%s: invalid or missing serial number\n",
> > +				dev_name(&cxlmd->dev));
> > +			rc = -ENXIO;
> > +			goto out_nvd;
> > +		}
> 
> Should we do the check earlier in the code? 
> For example, right below if (!nvdimm) {}
> 
> Fan

I agree. This would removes unnecessary struct value assignments
and make the code easier to read. Jonathan, what's your opinion?

Yuquan

> 
> >  		info[i].serial = cxlds->serial;
> >  	}
> >  	ndr_desc.num_mappings = cxlr_pmem->nr_mappings;
> > diff --git a/tools/testing/cxl/test/mem.c b/tools/testing/cxl/test/mem.c
> > index 8d731bd63988..9e098cf06603 100644
> > --- a/tools/testing/cxl/test/mem.c
> > +++ b/tools/testing/cxl/test/mem.c
> > @@ -1533,7 +1533,7 @@ static int cxl_mock_mem_probe(struct platform_device *pdev)
> >  	mds->event.buf = (struct cxl_get_event_payload *) mdata->event_buf;
> >  	INIT_DELAYED_WORK(&mds->security.poll_dwork, cxl_mockmem_sanitize_work);
> >  
> > -	cxlds->serial = pdev->id;
> > +	cxlds->serial = pdev->id + 1;
> >  	if (is_rcd(pdev))
> >  		cxlds->rcd = true;
> >  
> > -- 
> > 2.34.1
> > 

Re: [PATCH v3 1/1] cxl/pmem: debug invalid serial number data

[Jonathan Cameron]

On Tue, 18 Feb 2025 11:01:23 +0800
Yuquan Wang <wangyuquan1236@phytium.com.cn> wrote:

> On Mon, Feb 17, 2025 at 06:20:18PM -0800, Fan Ni wrote:
> > On Tue, Feb 18, 2025 at 09:47:46AM +0800, Yuquan Wang wrote:  
> > > In a nvdimm interleave-set each device with an invalid or zero
> > > serial number may cause pmem region initialization to fail, but in
> > > cxl case such device could still set cookies of nd_interleave_set
> > > and create a nvdimm pmem region.
> > > 
> > > This adds the validation of serial number in cxl pmem region creation.
> > > The event of no serial number would cause to fail to set the cookie
> > > and pmem region.
> > > 
> > > For cxl-test to work properly, always +1 on mock device's serial
> > > number.
> > > 
> > > Signed-off-by: Yuquan Wang <wangyuquan1236@phytium.com.cn>
> > > ---
> > >  drivers/cxl/pmem.c           | 8 ++++++++
> > >  tools/testing/cxl/test/mem.c | 2 +-
> > >  2 files changed, 9 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c
> > > index f9c95996e937..73787afe1b9d 100644
> > > --- a/drivers/cxl/pmem.c
> > > +++ b/drivers/cxl/pmem.c
> > > @@ -383,6 +383,14 @@ static int cxl_pmem_region_probe(struct device *dev)
> > >  			.position = i,
> > >  		};
> > >  		info[i].offset = m->start;
> > > +
> > > +		if (cxlds->serial == 0) {
> > > +			/* include missing alongside invalid in this error message. */
> > > +			dev_err(dev, "%s: invalid or missing serial number\n",
> > > +				dev_name(&cxlmd->dev));
> > > +			rc = -ENXIO;
> > > +			goto out_nvd;
> > > +		}  
> > 
> > Should we do the check earlier in the code? 
> > For example, right below if (!nvdimm) {}
> > 
> > Fan  
> 
> I agree. This would removes unnecessary struct value assignments
> and make the code easier to read. Jonathan, what's your opinion?
> 

Seems a bit odd to move it well clear of where it is used.  You could
pull these two info[i] lines up as well then it would seem more reasonable.

I don't mind that much though.

Jonathan

> Yuquan
> 
> >   
> > >  		info[i].serial = cxlds->serial;
> > >  	}
> > >  	ndr_desc.num_mappings = cxlr_pmem->nr_mappings;
> > > diff --git a/tools/testing/cxl/test/mem.c b/tools/testing/cxl/test/mem.c
> > > index 8d731bd63988..9e098cf06603 100644
> > > --- a/tools/testing/cxl/test/mem.c
> > > +++ b/tools/testing/cxl/test/mem.c
> > > @@ -1533,7 +1533,7 @@ static int cxl_mock_mem_probe(struct platform_device *pdev)
> > >  	mds->event.buf = (struct cxl_get_event_payload *) mdata->event_buf;
> > >  	INIT_DELAYED_WORK(&mds->security.poll_dwork, cxl_mockmem_sanitize_work);
> > >  
> > > -	cxlds->serial = pdev->id;
> > > +	cxlds->serial = pdev->id + 1;
> > >  	if (is_rcd(pdev))
> > >  		cxlds->rcd = true;
> > >  
> > > -- 
> > > 2.34.1
> > >   
> 
>