Re: [PATCH 1/3] drm/xe/oa: Use xe_map layer

["Dixit, Ashutosh" <ashutosh.dixit@intel.com>]

On Mon, 27 Apr 2026 12:34:24 -0700, Umesh Nerlige Ramappa wrote:
>
> On Mon, Apr 27, 2026 at 12:02:21PM -0700, Ashutosh Dixit wrote:
> > OA code should have used xe_map layer to begin with. In CRI, the OA buffer
> > can be located both in system and device memory. For these reasons, move OA
> > code to use the xe_map layer when accessing the OA buffer.
> >
> > v2: Use xe_map layer and put_user in xe_oa_copy_to_user (Umesh)
> > v3: To avoid performance impact in v2, revert to v1 but move
> >    xe_map_copy_to_user() to xe_map.h
> > v4: Use bounce buffer and copy_to_user in xe_oa_copy_to_user
> > v5: Fix offsets in oa_timestamp() and oa_timestamp_clear() (Umesh)
> > v6: Rename head/tail in helper args to report_offset (Umesh)
>
> Thanks for renaming. My comments are in the v5 version of the series.
>
> With an assert/check in the xe_oa_copy_to_user(), this should be

Add in v7. The only remaining comment is the one about the test, will make
a note of it.

>
> Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>

Thanks.
--
Ashutosh


>
> >
> > Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
> > ---
> > drivers/gpu/drm/xe/xe_oa.c       | 95 +++++++++++++++++++-------------
> > drivers/gpu/drm/xe/xe_oa_types.h |  4 +-
> > 2 files changed, 58 insertions(+), 41 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/xe/xe_oa.c b/drivers/gpu/drm/xe/xe_oa.c
> > index 6337e671c97ae..1fff0e8e9e78e 100644
> > --- a/drivers/gpu/drm/xe/xe_oa.c
> > +++ b/drivers/gpu/drm/xe/xe_oa.c
> > @@ -213,32 +213,40 @@ static u32 xe_oa_hw_tail_read(struct xe_oa_stream *stream)
> > #define oa_report_header_64bit(__s) \
> >	((__s)->oa_buffer.format->header == HDR_64_BIT)
> >
> > -static u64 oa_report_id(struct xe_oa_stream *stream, void *report)
> > +static u64 oa_report_id(struct xe_oa_stream *stream, u32 report_offset)
> > {
> > -	return oa_report_header_64bit(stream) ? *(u64 *)report : *(u32 *)report;
> > +	struct iosys_map *map = &stream->oa_buffer.bo->vmap;
> > +
> > +	return oa_report_header_64bit(stream) ?
> > +		xe_map_rd(stream->oa->xe, map, report_offset, u64) :
> > +		xe_map_rd(stream->oa->xe, map, report_offset, u32);
> > }
> >
> > -static void oa_report_id_clear(struct xe_oa_stream *stream, u32 *report)
> > +static void oa_report_id_clear(struct xe_oa_stream *stream, u32 report_offset)
> > {
> > -	if (oa_report_header_64bit(stream))
> > -		*(u64 *)report = 0;
> > -	else
> > -		*report = 0;
> > +	struct iosys_map *map = &stream->oa_buffer.bo->vmap;
> > +
> > +	oa_report_header_64bit(stream) ?
> > +		xe_map_wr(stream->oa->xe, map, report_offset, u64, 0) :
> > +		xe_map_wr(stream->oa->xe, map, report_offset, u32, 0);
> > }
> >
> > -static u64 oa_timestamp(struct xe_oa_stream *stream, void *report)
> > +static u64 oa_timestamp(struct xe_oa_stream *stream, u32 report_offset)
> > {
> > +	struct iosys_map *map = &stream->oa_buffer.bo->vmap;
> > +
> >	return oa_report_header_64bit(stream) ?
> > -		*((u64 *)report + 1) :
> > -		*((u32 *)report + 1);
> > +		xe_map_rd(stream->oa->xe, map, report_offset + 8, u64) :
> > +		xe_map_rd(stream->oa->xe, map, report_offset + 4, u32);
> > }
> >
> > -static void oa_timestamp_clear(struct xe_oa_stream *stream, u32 *report)
> > +static void oa_timestamp_clear(struct xe_oa_stream *stream, u32 report_offset)
> > {
> > -	if (oa_report_header_64bit(stream))
> > -		*(u64 *)&report[2] = 0;
> > -	else
> > -		report[1] = 0;
> > +	struct iosys_map *map = &stream->oa_buffer.bo->vmap;
> > +
> > +	oa_report_header_64bit(stream) ?
> > +		xe_map_wr(stream->oa->xe, map, report_offset + 8, u64, 0) :
> > +		xe_map_wr(stream->oa->xe, map, report_offset + 4, u32, 0);
> > }
> >
> > static bool xe_oa_buffer_check_unlocked(struct xe_oa_stream *stream)
> > @@ -275,9 +283,7 @@ static bool xe_oa_buffer_check_unlocked(struct xe_oa_stream *stream)
> >	 * they were written.  If not : (╯°□°）╯︵ ┻━┻
> >	 */
> >	while (xe_oa_circ_diff(stream, tail, stream->oa_buffer.tail) >= report_size) {
> > -		void *report = stream->oa_buffer.vaddr + tail;
> > -
> > -		if (oa_report_id(stream, report) || oa_timestamp(stream, report))
> > +		if (oa_report_id(stream, tail) || oa_timestamp(stream, tail))
> >			break;
> >
> >		tail = xe_oa_circ_diff(stream, tail, report_size);
> > @@ -311,30 +317,35 @@ static enum hrtimer_restart xe_oa_poll_check_timer_cb(struct hrtimer *hrtimer)
> >	return HRTIMER_RESTART;
> > }
> >
> > +static unsigned long
> > +xe_oa_copy_to_user(struct xe_oa_stream *stream, void __user *dst, u32 report_offset, u32 len)
> > +{
> > +	xe_map_memcpy_from(stream->oa->xe, stream->oa_buffer.bounce,
> > +			   &stream->oa_buffer.bo->vmap, report_offset, len);
> > +	return copy_to_user(dst, stream->oa_buffer.bounce, len);
> > +}
> > +
> > static int xe_oa_append_report(struct xe_oa_stream *stream, char __user *buf,
> > -			       size_t count, size_t *offset, const u8 *report)
> > +			       size_t count, size_t *offset, u32 report_offset)
> > {
> >	int report_size = stream->oa_buffer.format->size;
> >	int report_size_partial;
> > -	u8 *oa_buf_end;
> >
> >	if ((count - *offset) < report_size)
> >		return -ENOSPC;
> >
> >	buf += *offset;
> >
> > -	oa_buf_end = stream->oa_buffer.vaddr + stream->oa_buffer.circ_size;
> > -	report_size_partial = oa_buf_end - report;
> > +	report_size_partial = stream->oa_buffer.circ_size - report_offset;
> >
> >	if (report_size_partial < report_size) {
> > -		if (copy_to_user(buf, report, report_size_partial))
> > +		if (xe_oa_copy_to_user(stream, buf, report_offset, report_size_partial))
> >			return -EFAULT;
> >		buf += report_size_partial;
> >
> > -		if (copy_to_user(buf, stream->oa_buffer.vaddr,
> > -				 report_size - report_size_partial))
> > +		if (xe_oa_copy_to_user(stream, buf, 0, report_size - report_size_partial))
> >			return -EFAULT;
> > -	} else if (copy_to_user(buf, report, report_size)) {
> > +	} else if (xe_oa_copy_to_user(stream, buf, report_offset, report_size)) {
> >		return -EFAULT;
> >	}
> >
> > @@ -347,7 +358,6 @@ static int xe_oa_append_reports(struct xe_oa_stream *stream, char __user *buf,
> >				size_t count, size_t *offset)
> > {
> >	int report_size = stream->oa_buffer.format->size;
> > -	u8 *oa_buf_base = stream->oa_buffer.vaddr;
> >	u32 gtt_offset = xe_bo_ggtt_addr(stream->oa_buffer.bo);
> >	size_t start_offset = *offset;
> >	unsigned long flags;
> > @@ -364,26 +374,24 @@ static int xe_oa_append_reports(struct xe_oa_stream *stream, char __user *buf,
> >
> >	for (; xe_oa_circ_diff(stream, tail, head);
> >	     head = xe_oa_circ_incr(stream, head, report_size)) {
> > -		u8 *report = oa_buf_base + head;
> > -
> > -		ret = xe_oa_append_report(stream, buf, count, offset, report);
> > +		ret = xe_oa_append_report(stream, buf, count, offset, head);
> >		if (ret)
> >			break;
> >
> >		if (!(stream->oa_buffer.circ_size % report_size)) {
> >			/* Clear out report id and timestamp to detect unlanded reports */
> > -			oa_report_id_clear(stream, (void *)report);
> > -			oa_timestamp_clear(stream, (void *)report);
> > +			oa_report_id_clear(stream, head);
> > +			oa_timestamp_clear(stream, head);
> >		} else {
> > -			u8 *oa_buf_end = stream->oa_buffer.vaddr + stream->oa_buffer.circ_size;
> > -			u32 part = oa_buf_end - report;
> > +			struct iosys_map *map = &stream->oa_buffer.bo->vmap;
> > +			u32 part = stream->oa_buffer.circ_size - head;
> >
> >			/* Zero out the entire report */
> >			if (report_size <= part) {
> > -				memset(report, 0, report_size);
> > +				xe_map_memset(stream->oa->xe, map, head, 0, report_size);
> >			} else {
> > -				memset(report, 0, part);
> > -				memset(oa_buf_base, 0, report_size - part);
> > +				xe_map_memset(stream->oa->xe, map, head, 0, part);
> > +				xe_map_memset(stream->oa->xe, map, 0, 0, report_size - part);
> >			}
> >		}
> >	}
> > @@ -436,7 +444,8 @@ static void xe_oa_init_oa_buffer(struct xe_oa_stream *stream)
> >	spin_unlock_irqrestore(&stream->oa_buffer.ptr_lock, flags);
> >
> >	/* Zero out the OA buffer since we rely on zero report id and timestamp fields */
> > -	memset(stream->oa_buffer.vaddr, 0, xe_bo_size(stream->oa_buffer.bo));
> > +	xe_map_memset(stream->oa->xe, &stream->oa_buffer.bo->vmap, 0, 0,
> > +		      xe_bo_size(stream->oa_buffer.bo));
> > }
> >
> > static u32 __format_to_oactrl(const struct xe_oa_format *format, int counter_sel_mask)
> > @@ -699,6 +708,7 @@ static int num_lri_dwords(int num_regs)
> > static void xe_oa_free_oa_buffer(struct xe_oa_stream *stream)
> > {
> >	xe_bo_unpin_map_no_vm(stream->oa_buffer.bo);
> > +	kfree(stream->oa_buffer.bounce);
> > }
> >
> > static void xe_oa_free_configs(struct xe_oa_stream *stream)
> > @@ -889,9 +899,16 @@ static int xe_oa_alloc_oa_buffer(struct xe_oa_stream *stream, size_t size)
> >		return PTR_ERR(bo);
> >
> >	stream->oa_buffer.bo = bo;
> > +
> >	/* mmap implementation requires OA buffer to be in system memory */
> >	xe_assert(stream->oa->xe, bo->vmap.is_iomem == 0);
> > -	stream->oa_buffer.vaddr = bo->vmap.vaddr;
> > +
> > +	stream->oa_buffer.bounce = kmalloc(stream->oa_buffer.format->size, GFP_KERNEL);
> > +	if (!stream->oa_buffer.bounce) {
> > +		xe_bo_unpin_map_no_vm(stream->oa_buffer.bo);
> > +		return -ENOMEM;
> > +	}
> > +
> >	return 0;
> > }
> >
> > diff --git a/drivers/gpu/drm/xe/xe_oa_types.h b/drivers/gpu/drm/xe/xe_oa_types.h
> > index 8906c3084b5f8..3d9ec8490899c 100644
> > --- a/drivers/gpu/drm/xe/xe_oa_types.h
> > +++ b/drivers/gpu/drm/xe/xe_oa_types.h
> > @@ -164,8 +164,8 @@ struct xe_oa_buffer {
> >	/** @bo: xe_bo backing the OA buffer */
> >	struct xe_bo *bo;
> >
> > -	/** @vaddr: mapped vaddr of the OA buffer */
> > -	u8 *vaddr;
> > +	/** @bounce: bounce buffer used with xe_map layer */
> > +	void *bounce;
> >
> >	/** @ptr_lock: Lock protecting reads/writes to head/tail pointers */
> >	spinlock_t ptr_lock;
> > --
> > 2.54.0
> >