[PATCH 3/7] drm/xe: Add ring start to LRC snapshot

[Cavitt, Jonathan]

-----Original Message-----
From: Intel-xe <intel-xe-bounces at lists.freedesktop.org> On Behalf Of Matthew Brost
Sent: Friday, November 8, 2024 9:43 AM
To: intel-xe at lists.freedesktop.org
Cc: Teres Alexis, Alan Previn <alan.previn.teres.alexis at intel.com>; Dong, Zhanjun <zhanjun.dong at intel.com>; Vivi, Rodrigo <rodrigo.vivi at intel.com>
Subject: [PATCH 3/7] drm/xe: Add ring start to LRC snapshot
> 
> Add LRC ring start register to LRC snapshot to verify no LRC register
> corruption upon hang. This could be possible if the indirect ring state
> was mapped to user space or via an internal KMD memory corruption.
> 
> Signed-off-by: Matthew Brost <matthew.brost at intel.com>

Seems correct to me.
Reviewed-by: Jonathan Cavitt <jonathan.cavitt at intel.com>
-Jonathan Cavitt

> ---
>  drivers/gpu/drm/xe/xe_lrc.c | 10 ++++++++++
>  drivers/gpu/drm/xe/xe_lrc.h |  1 +
>  2 files changed, 11 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c
> index afb0f4f44748..80cb0e7e2d22 100644
> --- a/drivers/gpu/drm/xe/xe_lrc.c
> +++ b/drivers/gpu/drm/xe/xe_lrc.c
> @@ -1061,6 +1061,14 @@ u32 xe_lrc_ring_tail(struct xe_lrc *lrc)
>  		return xe_lrc_read_ctx_reg(lrc, CTX_RING_TAIL) & TAIL_ADDR;
>  }
>  
> +static u32 xe_lrc_ring_start(struct xe_lrc *lrc)
> +{
> +	if (xe_lrc_has_indirect_ring_state(lrc))
> +		return xe_lrc_read_indirect_ctx_reg(lrc, INDIRECT_CTX_RING_START);
> +	else
> +		return xe_lrc_read_ctx_reg(lrc, CTX_RING_START);
> +}
> +
>  void xe_lrc_set_ring_head(struct xe_lrc *lrc, u32 head)
>  {
>  	if (xe_lrc_has_indirect_ring_state(lrc))
> @@ -1641,6 +1649,7 @@ struct xe_lrc_snapshot *xe_lrc_snapshot_capture(struct xe_lrc *lrc)
>  	snapshot->head = xe_lrc_ring_head(lrc);
>  	snapshot->tail.internal = lrc->ring.tail;
>  	snapshot->tail.memory = xe_lrc_ring_tail(lrc);
> +	snapshot->start = xe_lrc_ring_start(lrc);
>  	snapshot->start_seqno = xe_lrc_start_seqno(lrc);
>  	snapshot->seqno = xe_lrc_seqno(lrc);
>  	snapshot->lrc_bo = xe_bo_get(lrc->bo);
> @@ -1701,6 +1710,7 @@ void xe_lrc_snapshot_print(struct xe_lrc_snapshot *snapshot, struct drm_printer
>  	drm_printf(p, "\tLRC Head: (memory) %u\n", snapshot->head);
>  	drm_printf(p, "\tLRC Tail: (internal) %u, (memory) %u\n",
>  		   snapshot->tail.internal, snapshot->tail.memory);
> +	drm_printf(p, "\tRing start: (memory) 0x%08x\n", snapshot->start);
>  	drm_printf(p, "\tStart seqno: (memory) %d\n", snapshot->start_seqno);
>  	drm_printf(p, "\tSeqno: (memory) %d\n", snapshot->seqno);
>  	drm_printf(p, "\tTimestamp: 0x%08x\n", snapshot->ctx_timestamp);
> diff --git a/drivers/gpu/drm/xe/xe_lrc.h b/drivers/gpu/drm/xe/xe_lrc.h
> index a2058a501353..a1b227440d1d 100644
> --- a/drivers/gpu/drm/xe/xe_lrc.h
> +++ b/drivers/gpu/drm/xe/xe_lrc.h
> @@ -28,6 +28,7 @@ struct xe_lrc_snapshot {
>  	u32 ring_desc;
>  	u32 indirect_context_desc;
>  	u32 head;
> +	u32 start;
>  	struct {
>  		u32 internal;
>  		u32 memory;
> -- 
> 2.34.1
> 
>