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

Ashutosh Dixit
2026-04-27T20:27:03Z

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)
v7: Add xe_assert in xe_oa_copy_to_user (Umesh)

Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
---
drivers/gpu/drm/xe/xe_oa.c | 97 +++++++++++++++++++-------------
drivers/gpu/drm/xe/xe_oa_types.h | 4 +-
2 files changed, 60 insertions(+), 41 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_oa.c b/drivers/gpu/drm/xe/xe_oa.c
index 6337e671c97ae..6ded3c2fce34e 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 +317,37 @@ 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_assert(stream->oa->xe, len <= stream->oa_buffer.format->size);
+
+ 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 +360,6 @@ 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 +376,24 @@ 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 +446,8 @@ 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 +710,7 @@ 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 +901,16 @@ 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