[PATCH v3 1/2] drm/amdgpu: Add a max ibs per submission limit.

[Bas Nieuwenhuizen]

And ensure each ring supports that many submissions. This makes
sure that we don't get surprises after the submission has been
scheduled where the ring allocation actually gets rejected.

Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2498
Signed-off-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c   |  3 +++
 drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c | 25 ++++++++++++++++++++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h |  1 +
 3 files changed, 29 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 7af3041ccd0e..8362738974c8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -110,6 +110,9 @@ static int amdgpu_cs_p1_ib(struct amdgpu_cs_parser *p,
 	if (r < 0)
 		return r;
 
+	if (num_ibs[r] >= amdgpu_ring_max_ibs(chunk_ib->ip_type))
+		return -EINVAL;
+
 	++(num_ibs[r]);
 	p->gang_leader_idx = r;
 	return 0;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
index dc474b809604..abd70d2f26f6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
@@ -49,6 +49,25 @@
  * them until the pointers are equal again.
  */
 
+/**
+ * amdgpu_ring_max_ibs - Return max IBs that fit in a single submission.
+ *
+ * @type: ring type for which to return the limit.
+ */
+unsigned int amdgpu_ring_max_ibs(enum amdgpu_ring_type type)
+{
+	switch (type) {
+	case AMDGPU_RING_TYPE_GFX:
+	case AMDGPU_RING_TYPE_COMPUTE:
+		/* gfx/compute are often used more extensively and radv
+		 * has historically assumed the limit was 192.
+		 */
+		return 192;
+	default:
+		return 50;
+	}
+}
+
 /**
  * amdgpu_ring_alloc - allocate space on the ring buffer
  *
@@ -182,6 +201,7 @@ int amdgpu_ring_init(struct amdgpu_device *adev, struct amdgpu_ring *ring,
 	int sched_hw_submission = amdgpu_sched_hw_submission;
 	u32 *num_sched;
 	u32 hw_ip;
+	unsigned int max_ibs_dw;
 
 	/* Set the hw submission limit higher for KIQ because
 	 * it's used for a number of gfx/compute tasks by both
@@ -290,6 +310,11 @@ int amdgpu_ring_init(struct amdgpu_device *adev, struct amdgpu_ring *ring,
 		return r;
 	}
 
+	max_ibs_dw = ring->funcs->emit_frame_size +
+		     amdgpu_ring_max_ibs(ring->funcs->type) * ring->funcs->emit_ib_size;
+	max_ibs_dw = (max_ibs_dw + ring->funcs->align_mask) & ~ring->funcs->align_mask;
+	max_dw = max(max_dw, max_ibs_dw);
+
 	ring->ring_size = roundup_pow_of_two(max_dw * 4 * sched_hw_submission);
 
 	ring->buf_mask = (ring->ring_size / 4) - 1;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
index 3989e755a5b4..e6e672727529 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
@@ -317,6 +317,7 @@ struct amdgpu_ring {
 #define amdgpu_ring_patch_cond_exec(r,o) (r)->funcs->patch_cond_exec((r),(o))
 #define amdgpu_ring_preempt_ib(r) (r)->funcs->preempt_ib(r)
 
+unsigned int amdgpu_ring_max_ibs(enum amdgpu_ring_type type);
 int amdgpu_ring_alloc(struct amdgpu_ring *ring, unsigned ndw);
 void amdgpu_ring_ib_begin(struct amdgpu_ring *ring);
 void amdgpu_ring_ib_end(struct amdgpu_ring *ring);
-- 
2.40.0