[PATCH v2] cxl/trace: Add an HPA to cxl_poison trace events

[PATCH v2] cxl/trace: Add an HPA to cxl_poison trace events

[alison.schofield]

From: Alison Schofield <alison.schofield@intel.com>

When a cxl_poison trace event is reported by region, the poisoned
Device Physical Address (DPA) can be translated to a Host Physical
Address (HPA) for consumption by user space.

Translate and add the resulting HPA to the cxl_poison trace event.
Follow the device decode logic as defined in the CXL Spec 3.0 Section
8.2.4.19.13.

When the poison request is by memdev, no HPA translation is performed
and ULLONG_MAX is assigned to the cxl_poison hpa trace field.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
---

Built on cxl/next plus Patchset: CXL Poison List Retrieval & Tracing [1]

Changes in v2:
- Rebased to cxl/next

Link to v1: https://lore.kernel.org/linux-cxl/20230104210401.195808-1-alison.schofield@intel.com/

[1] https://lore.kernel.org/linux-cxl/de11785ff05844299b40b100f8e0f56c7eef7f08.1674070170.git.alison.schofield@intel.com/


 drivers/cxl/core/trace.c | 94 ++++++++++++++++++++++++++++++++++++++++
 drivers/cxl/core/trace.h |  9 +++-
 2 files changed, 102 insertions(+), 1 deletion(-)

diff --git a/drivers/cxl/core/trace.c b/drivers/cxl/core/trace.c
index 29ae7ce81dc5..d0403dc3c8ab 100644
--- a/drivers/cxl/core/trace.c
+++ b/drivers/cxl/core/trace.c
@@ -1,5 +1,99 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /* Copyright(c) 2022 Intel Corporation. All rights reserved. */
 
+#include <cxl.h>
+#include "core.h"
+
 #define CREATE_TRACE_POINTS
 #include "trace.h"
+
+static bool cxl_is_hpa_in_range(u64 hpa, struct cxl_region *cxlr, int pos)
+{
+	struct cxl_region_params *p = &cxlr->params;
+	int gran = p->interleave_granularity;
+	int ways = p->interleave_ways;
+	u64 offset;
+
+	/* Is the hpa within this region at all */
+	if (hpa < p->res->start || hpa > p->res->end) {
+		dev_dbg(&cxlr->dev,
+			"Addr trans fail: hpa 0x%llx not in region\n", hpa);
+		return false;
+	}
+
+	/* Is the hpa in an expected chunk for its pos(-ition) */
+	offset = hpa - p->res->start;
+	offset = do_div(offset, gran * ways);
+	if ((offset >= pos * gran) && (offset < (pos + 1) * gran))
+		return true;
+
+	dev_dbg(&cxlr->dev,
+		"Addr trans fail: hpa 0x%llx not in expected chunk\n", hpa);
+
+	return false;
+}
+
+static u64 cxl_dpa_to_hpa(u64 dpa,  struct cxl_region *cxlr,
+			  struct cxl_endpoint_decoder *cxled)
+{
+	u64 dpa_offset, hpa_offset, bits_upper, mask_upper, hpa;
+	struct cxl_region_params *p = &cxlr->params;
+	int pos = cxled->pos;
+	u16 eig = 0;
+	u8 eiw = 0;
+
+	ways_to_eiw(p->interleave_ways, &eiw);
+	granularity_to_eig(p->interleave_granularity, &eig);
+
+	/*
+	 * The device position in the region interleave set was removed
+	 * from the offset at HPA->DPA translation. To reconstruct the
+	 * HPA, place the 'pos' in the offset.
+	 *
+	 * The placement of 'pos' in the HPA is determined by interleave
+	 * ways and granularity and is defined in the CXL Spec 3.0 Section
+	 * 8.2.4.19.13 Implementation Note: Device Decode Logic
+	 */
+
+	/* Remove the dpa base */
+	dpa_offset = dpa - cxl_dpa_resource_start(cxled);
+
+	mask_upper = GENMASK_ULL(51, eig + 8);
+
+	if (eiw < 8) {
+		hpa_offset = (dpa_offset & mask_upper) << eiw;
+		hpa_offset |= pos << (eig + 8);
+	} else {
+		bits_upper = (dpa_offset & mask_upper) >> (eig + 8);
+		bits_upper = bits_upper * 3;
+		hpa_offset = ((bits_upper << (eiw - 8)) + pos) << (eig + 8);
+	}
+
+	/* The lower bits remain unchanged */
+	hpa_offset |= dpa_offset & GENMASK_ULL(eig + 7, 0);
+
+	/* Apply the hpa_offset to the region base address */
+	hpa = hpa_offset + p->res->start;
+
+	if (!cxl_is_hpa_in_range(hpa, cxlr, cxled->pos))
+		return ULLONG_MAX;
+
+	return hpa;
+}
+
+u64 cxl_trace_hpa(struct cxl_region *cxlr, struct cxl_memdev *cxlmd,
+		  u64 dpa)
+{
+	struct cxl_region_params *p = &cxlr->params;
+	struct cxl_endpoint_decoder *cxled = NULL;
+
+	for (int i = 0; i <  p->nr_targets; i++) {
+		cxled = p->targets[i];
+		if (cxlmd == cxled_to_memdev(cxled))
+			break;
+	}
+	if (!cxled || cxlmd != cxled_to_memdev(cxled))
+		return ULLONG_MAX;
+
+	return cxl_dpa_to_hpa(dpa, cxlr, cxled);
+}
diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h
index c7958311ce5f..521b80f92e96 100644
--- a/drivers/cxl/core/trace.h
+++ b/drivers/cxl/core/trace.h
@@ -136,6 +136,8 @@ TRACE_EVENT(cxl_aer_correctable_error,
 #define cxl_poison_overflow(flags, time)				\
 	(flags & CXL_POISON_FLAG_OVERFLOW ? le64_to_cpu(time) : 0)
 
+u64 cxl_trace_hpa(struct cxl_region *cxlr, struct cxl_memdev *memdev, u64 dpa);
+
 TRACE_EVENT(cxl_poison,
 
 	    TP_PROTO(struct cxl_memdev *memdev, const struct pci_dev *pcidev,
@@ -150,6 +152,7 @@ TRACE_EVENT(cxl_poison,
 		__string(pcidev, dev_name(&pcidev->dev))
 		__string(region, region)
 		__field(u64, overflow_t)
+		__field(u64, hpa)
 		__field(u64, dpa)
 		__field(u32, length)
 		__array(char, uuid, 16)
@@ -168,17 +171,21 @@ TRACE_EVENT(cxl_poison,
 		if (region) {
 			__assign_str(region, dev_name(&region->dev));
 			memcpy(__entry->uuid, &region->params.uuid, 16);
+			__entry->hpa = cxl_trace_hpa(region, memdev,
+						     __entry->dpa);
 		} else {
 			__assign_str(region, "");
 			memset(__entry->uuid, 0, 16);
+			__entry->hpa = ULLONG_MAX;
 		}
 	    ),
 
-	    TP_printk("memdev=%s pcidev=%s region=%s region_uuid=%pU dpa=0x%llx length=0x%x source=%s flags=%s overflow_time=%llu",
+	    TP_printk("memdev=%s pcidev=%s region=%s region_uuid=%pU hpa=0x%llx dpa=0x%llx length=0x%x source=%s flags=%s overflow_time=%llu",
 		__get_str(memdev),
 		__get_str(pcidev),
 		__get_str(region),
 		__entry->uuid,
+		__entry->hpa,
 		__entry->dpa,
 		__entry->length,
 		show_poison_source(__entry->source),
-- 
2.37.3

Re: [PATCH v2] cxl/trace: Add an HPA to cxl_poison trace events

[Jonathan Cameron]

On Wed, 18 Jan 2023 12:18:05 -0800
alison.schofield@intel.com wrote:

> From: Alison Schofield <alison.schofield@intel.com>
> 
> When a cxl_poison trace event is reported by region, the poisoned
> Device Physical Address (DPA) can be translated to a Host Physical
> Address (HPA) for consumption by user space.
> 
> Translate and add the resulting HPA to the cxl_poison trace event.
> Follow the device decode logic as defined in the CXL Spec 3.0 Section
> 8.2.4.19.13.
> 
> When the poison request is by memdev, no HPA translation is performed
> and ULLONG_MAX is assigned to the cxl_poison hpa trace field.
> 
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>

The offset stuff for non power of 2 gives me a headache, but I 'think'
you have it right... We don't yet have support in QEMU for those
modes, so I can't easily brute force test it.  With all that in mind.


Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Trivial style comment inline.

> ---
> 
> Built on cxl/next plus Patchset: CXL Poison List Retrieval & Tracing [1]
> 
> Changes in v2:
> - Rebased to cxl/next
> 
> Link to v1: https://lore.kernel.org/linux-cxl/20230104210401.195808-1-alison.schofield@intel.com/
> 
> [1] https://lore.kernel.org/linux-cxl/de11785ff05844299b40b100f8e0f56c7eef7f08.1674070170.git.alison.schofield@intel.com/
> 
> 
>  drivers/cxl/core/trace.c | 94 ++++++++++++++++++++++++++++++++++++++++
>  drivers/cxl/core/trace.h |  9 +++-
>  2 files changed, 102 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cxl/core/trace.c b/drivers/cxl/core/trace.c
> index 29ae7ce81dc5..d0403dc3c8ab 100644
> --- a/drivers/cxl/core/trace.c
> +++ b/drivers/cxl/core/trace.c
> @@ -1,5 +1,99 @@
>  // SPDX-License-Identifier: GPL-2.0-only
>  /* Copyright(c) 2022 Intel Corporation. All rights reserved. */
>  
> +#include <cxl.h>
> +#include "core.h"
> +
>  #define CREATE_TRACE_POINTS
>  #include "trace.h"
> +
> +static bool cxl_is_hpa_in_range(u64 hpa, struct cxl_region *cxlr, int pos)
> +{
> +	struct cxl_region_params *p = &cxlr->params;
> +	int gran = p->interleave_granularity;
> +	int ways = p->interleave_ways;
> +	u64 offset;
> +
> +	/* Is the hpa within this region at all */

For comments we could go with HPA... Doesn't really matter though.

 
> +	if (hpa < p->res->start || hpa > p->res->end) {
> +		dev_dbg(&cxlr->dev,
> +			"Addr trans fail: hpa 0x%llx not in region\n", hpa);
> +		return false;
> +	}
> +
> +	/* Is the hpa in an expected chunk for its pos(-ition) */
> +	offset = hpa - p->res->start;
> +	offset = do_div(offset, gran * ways);
> +	if ((offset >= pos * gran) && (offset < (pos + 1) * gran))
> +		return true;
> +
> +	dev_dbg(&cxlr->dev,
> +		"Addr trans fail: hpa 0x%llx not in expected chunk\n", hpa);
> +
> +	return false;
> +}
> +
> +static u64 cxl_dpa_to_hpa(u64 dpa,  struct cxl_region *cxlr,
> +			  struct cxl_endpoint_decoder *cxled)
> +{
> +	u64 dpa_offset, hpa_offset, bits_upper, mask_upper, hpa;
> +	struct cxl_region_params *p = &cxlr->params;
> +	int pos = cxled->pos;
> +	u16 eig = 0;
> +	u8 eiw = 0;
> +
> +	ways_to_eiw(p->interleave_ways, &eiw);
> +	granularity_to_eig(p->interleave_granularity, &eig);
> +
> +	/*
> +	 * The device position in the region interleave set was removed
> +	 * from the offset at HPA->DPA translation. To reconstruct the
> +	 * HPA, place the 'pos' in the offset.
> +	 *
> +	 * The placement of 'pos' in the HPA is determined by interleave
> +	 * ways and granularity and is defined in the CXL Spec 3.0 Section
> +	 * 8.2.4.19.13 Implementation Note: Device Decode Logic
> +	 */
> +
> +	/* Remove the dpa base */
> +	dpa_offset = dpa - cxl_dpa_resource_start(cxled);
> +
> +	mask_upper = GENMASK_ULL(51, eig + 8);
> +
> +	if (eiw < 8) {
> +		hpa_offset = (dpa_offset & mask_upper) << eiw;
> +		hpa_offset |= pos << (eig + 8);
> +	} else {
> +		bits_upper = (dpa_offset & mask_upper) >> (eig + 8);
> +		bits_upper = bits_upper * 3;
> +		hpa_offset = ((bits_upper << (eiw - 8)) + pos) << (eig + 8);
> +	}
> +
> +	/* The lower bits remain unchanged */
> +	hpa_offset |= dpa_offset & GENMASK_ULL(eig + 7, 0);
> +
> +	/* Apply the hpa_offset to the region base address */
> +	hpa = hpa_offset + p->res->start;
> +
> +	if (!cxl_is_hpa_in_range(hpa, cxlr, cxled->pos))
> +		return ULLONG_MAX;
> +
> +	return hpa;
> +}
> +

> diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h
> index c7958311ce5f..521b80f92e96 100644
> --- a/drivers/cxl/core/trace.h
> +++ b/drivers/cxl/core/trace.h
> @@ -136,6 +136,8 @@ TRACE_EVENT(cxl_aer_correctable_error,
>  #define cxl_poison_overflow(flags, time)				\
>  	(flags & CXL_POISON_FLAG_OVERFLOW ? le64_to_cpu(time) : 0)
>  
> +u64 cxl_trace_hpa(struct cxl_region *cxlr, struct cxl_memdev *memdev, u64 dpa);
> +
>  TRACE_EVENT(cxl_poison,
>  
>  	    TP_PROTO(struct cxl_memdev *memdev, const struct pci_dev *pcidev,
> @@ -150,6 +152,7 @@ TRACE_EVENT(cxl_poison,
>  		__string(pcidev, dev_name(&pcidev->dev))
>  		__string(region, region)
>  		__field(u64, overflow_t)
> +		__field(u64, hpa)
>  		__field(u64, dpa)
>  		__field(u32, length)
>  		__array(char, uuid, 16)
> @@ -168,17 +171,21 @@ TRACE_EVENT(cxl_poison,
>  		if (region) {
>  			__assign_str(region, dev_name(&region->dev));
>  			memcpy(__entry->uuid, &region->params.uuid, 16);
> +			__entry->hpa = cxl_trace_hpa(region, memdev,
> +						     __entry->dpa);
>  		} else {
>  			__assign_str(region, "");
>  			memset(__entry->uuid, 0, 16);
> +			__entry->hpa = ULLONG_MAX;
>  		}
>  	    ),
>  
> -	    TP_printk("memdev=%s pcidev=%s region=%s region_uuid=%pU dpa=0x%llx length=0x%x source=%s flags=%s overflow_time=%llu",
> +	    TP_printk("memdev=%s pcidev=%s region=%s region_uuid=%pU hpa=0x%llx dpa=0x%llx length=0x%x source=%s flags=%s overflow_time=%llu",
>  		__get_str(memdev),
>  		__get_str(pcidev),
>  		__get_str(region),
>  		__entry->uuid,
> +		__entry->hpa,
>  		__entry->dpa,
>  		__entry->length,
>  		show_poison_source(__entry->source),

Re: [PATCH v2] cxl/trace: Add an HPA to cxl_poison trace events

[Alison Schofield]

On Mon, Jan 23, 2023 at 02:58:48PM +0000, Jonathan Cameron wrote:
> On Wed, 18 Jan 2023 12:18:05 -0800
> alison.schofield@intel.com wrote:
> 
> > From: Alison Schofield <alison.schofield@intel.com>
> > 
> > When a cxl_poison trace event is reported by region, the poisoned
> > Device Physical Address (DPA) can be translated to a Host Physical
> > Address (HPA) for consumption by user space.
> > 
> > Translate and add the resulting HPA to the cxl_poison trace event.
> > Follow the device decode logic as defined in the CXL Spec 3.0 Section
> > 8.2.4.19.13.
> > 
> > When the poison request is by memdev, no HPA translation is performed
> > and ULLONG_MAX is assigned to the cxl_poison hpa trace field.
> > 
> > Signed-off-by: Alison Schofield <alison.schofield@intel.com>
> 
> The offset stuff for non power of 2 gives me a headache, but I 'think'
> you have it right... We don't yet have support in QEMU for those
> modes, so I can't easily brute force test it.  With all that in mind.
> 
> 
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> 
> Trivial style comment inline.
> 
Thanks for the review Jonathan. I noted the comment hpa->HPA, and will
pick it up if/when I rev this.

Thanks for sharing the headache with me ;)  I posted a test program to
that mimics these calculations and cranks thru every (perhaps some
illegal) permuation of EIG, EIW, POS, and applies them to a dpa_offset
to make an hpa_offset.

https://github.com/AlisonSchofield/cxl-addrtest

Ideally, I would be able to compare the outputs I'm getting, rather
than just validate using my own, possibly flawed again, calculations.

Ideas to further that testing are welcome!

Alison


> > ---
> > 
> > Built on cxl/next plus Patchset: CXL Poison List Retrieval & Tracing [1]
> > 
> > Changes in v2:
> > - Rebased to cxl/next
> > 
> > Link to v1: https://lore.kernel.org/linux-cxl/20230104210401.195808-1-alison.schofield@intel.com/
> > 
> > [1] https://lore.kernel.org/linux-cxl/de11785ff05844299b40b100f8e0f56c7eef7f08.1674070170.git.alison.schofield@intel.com/
> > 
> > 
> >  drivers/cxl/core/trace.c | 94 ++++++++++++++++++++++++++++++++++++++++
> >  drivers/cxl/core/trace.h |  9 +++-
> >  2 files changed, 102 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/cxl/core/trace.c b/drivers/cxl/core/trace.c
> > index 29ae7ce81dc5..d0403dc3c8ab 100644
> > --- a/drivers/cxl/core/trace.c
> > +++ b/drivers/cxl/core/trace.c
> > @@ -1,5 +1,99 @@
> >  // SPDX-License-Identifier: GPL-2.0-only
> >  /* Copyright(c) 2022 Intel Corporation. All rights reserved. */
> >  
> > +#include <cxl.h>
> > +#include "core.h"
> > +
> >  #define CREATE_TRACE_POINTS
> >  #include "trace.h"
> > +
> > +static bool cxl_is_hpa_in_range(u64 hpa, struct cxl_region *cxlr, int pos)
> > +{
> > +	struct cxl_region_params *p = &cxlr->params;
> > +	int gran = p->interleave_granularity;
> > +	int ways = p->interleave_ways;
> > +	u64 offset;
> > +
> > +	/* Is the hpa within this region at all */
> 
> For comments we could go with HPA... Doesn't really matter though.
> 
>  
> > +	if (hpa < p->res->start || hpa > p->res->end) {
> > +		dev_dbg(&cxlr->dev,
> > +			"Addr trans fail: hpa 0x%llx not in region\n", hpa);
> > +		return false;
> > +	}
> > +
> > +	/* Is the hpa in an expected chunk for its pos(-ition) */
> > +	offset = hpa - p->res->start;
> > +	offset = do_div(offset, gran * ways);
> > +	if ((offset >= pos * gran) && (offset < (pos + 1) * gran))
> > +		return true;
> > +
> > +	dev_dbg(&cxlr->dev,
> > +		"Addr trans fail: hpa 0x%llx not in expected chunk\n", hpa);
> > +
> > +	return false;
> > +}
> > +
> > +static u64 cxl_dpa_to_hpa(u64 dpa,  struct cxl_region *cxlr,
> > +			  struct cxl_endpoint_decoder *cxled)
> > +{
> > +	u64 dpa_offset, hpa_offset, bits_upper, mask_upper, hpa;
> > +	struct cxl_region_params *p = &cxlr->params;
> > +	int pos = cxled->pos;
> > +	u16 eig = 0;
> > +	u8 eiw = 0;
> > +
> > +	ways_to_eiw(p->interleave_ways, &eiw);
> > +	granularity_to_eig(p->interleave_granularity, &eig);
> > +
> > +	/*
> > +	 * The device position in the region interleave set was removed
> > +	 * from the offset at HPA->DPA translation. To reconstruct the
> > +	 * HPA, place the 'pos' in the offset.
> > +	 *
> > +	 * The placement of 'pos' in the HPA is determined by interleave
> > +	 * ways and granularity and is defined in the CXL Spec 3.0 Section
> > +	 * 8.2.4.19.13 Implementation Note: Device Decode Logic
> > +	 */
> > +
> > +	/* Remove the dpa base */
> > +	dpa_offset = dpa - cxl_dpa_resource_start(cxled);
> > +
> > +	mask_upper = GENMASK_ULL(51, eig + 8);
> > +
> > +	if (eiw < 8) {
> > +		hpa_offset = (dpa_offset & mask_upper) << eiw;
> > +		hpa_offset |= pos << (eig + 8);
> > +	} else {
> > +		bits_upper = (dpa_offset & mask_upper) >> (eig + 8);
> > +		bits_upper = bits_upper * 3;
> > +		hpa_offset = ((bits_upper << (eiw - 8)) + pos) << (eig + 8);
> > +	}
> > +
> > +	/* The lower bits remain unchanged */
> > +	hpa_offset |= dpa_offset & GENMASK_ULL(eig + 7, 0);
> > +
> > +	/* Apply the hpa_offset to the region base address */
> > +	hpa = hpa_offset + p->res->start;
> > +
> > +	if (!cxl_is_hpa_in_range(hpa, cxlr, cxled->pos))
> > +		return ULLONG_MAX;
> > +
> > +	return hpa;
> > +}
> > +
> 
> > diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h
> > index c7958311ce5f..521b80f92e96 100644
> > --- a/drivers/cxl/core/trace.h
> > +++ b/drivers/cxl/core/trace.h
> > @@ -136,6 +136,8 @@ TRACE_EVENT(cxl_aer_correctable_error,
> >  #define cxl_poison_overflow(flags, time)				\
> >  	(flags & CXL_POISON_FLAG_OVERFLOW ? le64_to_cpu(time) : 0)
> >  
> > +u64 cxl_trace_hpa(struct cxl_region *cxlr, struct cxl_memdev *memdev, u64 dpa);
> > +
> >  TRACE_EVENT(cxl_poison,
> >  
> >  	    TP_PROTO(struct cxl_memdev *memdev, const struct pci_dev *pcidev,
> > @@ -150,6 +152,7 @@ TRACE_EVENT(cxl_poison,
> >  		__string(pcidev, dev_name(&pcidev->dev))
> >  		__string(region, region)
> >  		__field(u64, overflow_t)
> > +		__field(u64, hpa)
> >  		__field(u64, dpa)
> >  		__field(u32, length)
> >  		__array(char, uuid, 16)
> > @@ -168,17 +171,21 @@ TRACE_EVENT(cxl_poison,
> >  		if (region) {
> >  			__assign_str(region, dev_name(&region->dev));
> >  			memcpy(__entry->uuid, &region->params.uuid, 16);
> > +			__entry->hpa = cxl_trace_hpa(region, memdev,
> > +						     __entry->dpa);
> >  		} else {
> >  			__assign_str(region, "");
> >  			memset(__entry->uuid, 0, 16);
> > +			__entry->hpa = ULLONG_MAX;
> >  		}
> >  	    ),
> >  
> > -	    TP_printk("memdev=%s pcidev=%s region=%s region_uuid=%pU dpa=0x%llx length=0x%x source=%s flags=%s overflow_time=%llu",
> > +	    TP_printk("memdev=%s pcidev=%s region=%s region_uuid=%pU hpa=0x%llx dpa=0x%llx length=0x%x source=%s flags=%s overflow_time=%llu",
> >  		__get_str(memdev),
> >  		__get_str(pcidev),
> >  		__get_str(region),
> >  		__entry->uuid,
> > +		__entry->hpa,
> >  		__entry->dpa,
> >  		__entry->length,
> >  		show_poison_source(__entry->source),
> 

Re: [PATCH v2] cxl/trace: Add an HPA to cxl_poison trace events

[Dave Jiang]

On 1/18/23 1:18 PM, alison.schofield@intel.com wrote:
> From: Alison Schofield <alison.schofield@intel.com>
> 
> When a cxl_poison trace event is reported by region, the poisoned
> Device Physical Address (DPA) can be translated to a Host Physical
> Address (HPA) for consumption by user space.
> 
> Translate and add the resulting HPA to the cxl_poison trace event.
> Follow the device decode logic as defined in the CXL Spec 3.0 Section
> 8.2.4.19.13.
> 
> When the poison request is by memdev, no HPA translation is performed
> and ULLONG_MAX is assigned to the cxl_poison hpa trace field.
> 
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>

> ---
> 
> Built on cxl/next plus Patchset: CXL Poison List Retrieval & Tracing [1]
> 
> Changes in v2:
> - Rebased to cxl/next
> 
> Link to v1: https://lore.kernel.org/linux-cxl/20230104210401.195808-1-alison.schofield@intel.com/
> 
> [1] https://lore.kernel.org/linux-cxl/de11785ff05844299b40b100f8e0f56c7eef7f08.1674070170.git.alison.schofield@intel.com/
> 
> 
>   drivers/cxl/core/trace.c | 94 ++++++++++++++++++++++++++++++++++++++++
>   drivers/cxl/core/trace.h |  9 +++-
>   2 files changed, 102 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cxl/core/trace.c b/drivers/cxl/core/trace.c
> index 29ae7ce81dc5..d0403dc3c8ab 100644
> --- a/drivers/cxl/core/trace.c
> +++ b/drivers/cxl/core/trace.c
> @@ -1,5 +1,99 @@
>   // SPDX-License-Identifier: GPL-2.0-only
>   /* Copyright(c) 2022 Intel Corporation. All rights reserved. */
>   
> +#include <cxl.h>
> +#include "core.h"
> +
>   #define CREATE_TRACE_POINTS
>   #include "trace.h"
> +
> +static bool cxl_is_hpa_in_range(u64 hpa, struct cxl_region *cxlr, int pos)
> +{
> +	struct cxl_region_params *p = &cxlr->params;
> +	int gran = p->interleave_granularity;
> +	int ways = p->interleave_ways;
> +	u64 offset;
> +
> +	/* Is the hpa within this region at all */
> +	if (hpa < p->res->start || hpa > p->res->end) {
> +		dev_dbg(&cxlr->dev,
> +			"Addr trans fail: hpa 0x%llx not in region\n", hpa);
> +		return false;
> +	}
> +
> +	/* Is the hpa in an expected chunk for its pos(-ition) */
> +	offset = hpa - p->res->start;
> +	offset = do_div(offset, gran * ways);
> +	if ((offset >= pos * gran) && (offset < (pos + 1) * gran))
> +		return true;
> +
> +	dev_dbg(&cxlr->dev,
> +		"Addr trans fail: hpa 0x%llx not in expected chunk\n", hpa);
> +
> +	return false;
> +}
> +
> +static u64 cxl_dpa_to_hpa(u64 dpa,  struct cxl_region *cxlr,
> +			  struct cxl_endpoint_decoder *cxled)
> +{
> +	u64 dpa_offset, hpa_offset, bits_upper, mask_upper, hpa;
> +	struct cxl_region_params *p = &cxlr->params;
> +	int pos = cxled->pos;
> +	u16 eig = 0;
> +	u8 eiw = 0;
> +
> +	ways_to_eiw(p->interleave_ways, &eiw);
> +	granularity_to_eig(p->interleave_granularity, &eig);
> +
> +	/*
> +	 * The device position in the region interleave set was removed
> +	 * from the offset at HPA->DPA translation. To reconstruct the
> +	 * HPA, place the 'pos' in the offset.
> +	 *
> +	 * The placement of 'pos' in the HPA is determined by interleave
> +	 * ways and granularity and is defined in the CXL Spec 3.0 Section
> +	 * 8.2.4.19.13 Implementation Note: Device Decode Logic
> +	 */
> +
> +	/* Remove the dpa base */
> +	dpa_offset = dpa - cxl_dpa_resource_start(cxled);
> +
> +	mask_upper = GENMASK_ULL(51, eig + 8);
> +
> +	if (eiw < 8) {
> +		hpa_offset = (dpa_offset & mask_upper) << eiw;
> +		hpa_offset |= pos << (eig + 8);
> +	} else {
> +		bits_upper = (dpa_offset & mask_upper) >> (eig + 8);
> +		bits_upper = bits_upper * 3;
> +		hpa_offset = ((bits_upper << (eiw - 8)) + pos) << (eig + 8);
> +	}
> +
> +	/* The lower bits remain unchanged */
> +	hpa_offset |= dpa_offset & GENMASK_ULL(eig + 7, 0);
> +
> +	/* Apply the hpa_offset to the region base address */
> +	hpa = hpa_offset + p->res->start;
> +
> +	if (!cxl_is_hpa_in_range(hpa, cxlr, cxled->pos))
> +		return ULLONG_MAX;
> +
> +	return hpa;
> +}
> +
> +u64 cxl_trace_hpa(struct cxl_region *cxlr, struct cxl_memdev *cxlmd,
> +		  u64 dpa)
> +{
> +	struct cxl_region_params *p = &cxlr->params;
> +	struct cxl_endpoint_decoder *cxled = NULL;
> +
> +	for (int i = 0; i <  p->nr_targets; i++) {
> +		cxled = p->targets[i];
> +		if (cxlmd == cxled_to_memdev(cxled))
> +			break;
> +	}
> +	if (!cxled || cxlmd != cxled_to_memdev(cxled))
> +		return ULLONG_MAX;
> +
> +	return cxl_dpa_to_hpa(dpa, cxlr, cxled);
> +}
> diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h
> index c7958311ce5f..521b80f92e96 100644
> --- a/drivers/cxl/core/trace.h
> +++ b/drivers/cxl/core/trace.h
> @@ -136,6 +136,8 @@ TRACE_EVENT(cxl_aer_correctable_error,
>   #define cxl_poison_overflow(flags, time)				\
>   	(flags & CXL_POISON_FLAG_OVERFLOW ? le64_to_cpu(time) : 0)
>   
> +u64 cxl_trace_hpa(struct cxl_region *cxlr, struct cxl_memdev *memdev, u64 dpa);
> +
>   TRACE_EVENT(cxl_poison,
>   
>   	    TP_PROTO(struct cxl_memdev *memdev, const struct pci_dev *pcidev,
> @@ -150,6 +152,7 @@ TRACE_EVENT(cxl_poison,
>   		__string(pcidev, dev_name(&pcidev->dev))
>   		__string(region, region)
>   		__field(u64, overflow_t)
> +		__field(u64, hpa)
>   		__field(u64, dpa)
>   		__field(u32, length)
>   		__array(char, uuid, 16)
> @@ -168,17 +171,21 @@ TRACE_EVENT(cxl_poison,
>   		if (region) {
>   			__assign_str(region, dev_name(&region->dev));
>   			memcpy(__entry->uuid, &region->params.uuid, 16);
> +			__entry->hpa = cxl_trace_hpa(region, memdev,
> +						     __entry->dpa);
>   		} else {
>   			__assign_str(region, "");
>   			memset(__entry->uuid, 0, 16);
> +			__entry->hpa = ULLONG_MAX;
>   		}
>   	    ),
>   
> -	    TP_printk("memdev=%s pcidev=%s region=%s region_uuid=%pU dpa=0x%llx length=0x%x source=%s flags=%s overflow_time=%llu",
> +	    TP_printk("memdev=%s pcidev=%s region=%s region_uuid=%pU hpa=0x%llx dpa=0x%llx length=0x%x source=%s flags=%s overflow_time=%llu",
>   		__get_str(memdev),
>   		__get_str(pcidev),
>   		__get_str(region),
>   		__entry->uuid,
> +		__entry->hpa,
>   		__entry->dpa,
>   		__entry->length,
>   		show_poison_source(__entry->source),