On 17/05/2022 04:20, Matt Roper wrote:
Storing the EU mask internally in the same format the I915_QUERY
topology queries use makes the final copy_to_user() a bit simpler, but
makes the rest of the driver's SSEU more complicated and harder to
follow. Let's switch to an internal representation that's more natural:
Xe_HP platforms will be a simple array of u16 masks, whereas pre-Xe_HP
platforms will be a two-dimensional array, indexed by [slice][subslice].
We'll convert to the uapi format only when the query uapi is called.
v2:
- Drop has_common_ss_eumask. We waste some space repeating identical
EU masks for every single DSS, but the code is simpler without it.
(Tvrtko)
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>
Signed-off-by: Matt Roper <matthew.d.roper@xxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_sseu.c | 77 +++++++++++++++++++---------
drivers/gpu/drm/i915/gt/intel_sseu.h | 9 +++-
drivers/gpu/drm/i915/i915_query.c | 8 +--
3 files changed, 65 insertions(+), 29 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_sseu.c b/drivers/gpu/drm/i915/gt/intel_sseu.c
index ade3e1805782..d89e2e0f05e5 100644
--- a/drivers/gpu/drm/i915/gt/intel_sseu.c
+++ b/drivers/gpu/drm/i915/gt/intel_sseu.c
@@ -78,47 +78,76 @@ intel_sseu_subslices_per_slice(const struct sseu_dev_info *sseu, u8 slice)
return hweight32(intel_sseu_get_subslices(sseu, slice));
}
-static int sseu_eu_idx(const struct sseu_dev_info *sseu, int slice,
- int subslice)
-{
- int slice_stride = sseu->max_subslices * sseu->eu_stride;
-
- return slice * slice_stride + subslice * sseu->eu_stride;
-}
-
static u16 sseu_get_eus(const struct sseu_dev_info *sseu, int slice,
int subslice)
{
- int i, offset = sseu_eu_idx(sseu, slice, subslice);
- u16 eu_mask = 0;
-
- for (i = 0; i < sseu->eu_stride; i++)
- eu_mask |=
- ((u16)sseu->eu_mask[offset + i]) << (i * BITS_PER_BYTE);
-
- return eu_mask;
+ if (sseu->has_xehp_dss) {
+ WARN_ON(slice > 0);
+ return sseu->eu_mask.xehp[subslice];
+ } else {
+ return sseu->eu_mask.hsw[slice][subslice];
+ }
}
static void sseu_set_eus(struct sseu_dev_info *sseu, int slice, int subslice,
u16 eu_mask)
{
- int i, offset = sseu_eu_idx(sseu, slice, subslice);
-
- for (i = 0; i < sseu->eu_stride; i++)
- sseu->eu_mask[offset + i] =
- (eu_mask >> (BITS_PER_BYTE * i)) & 0xff;
+ if (sseu->has_xehp_dss) {
+ WARN_ON(slice > 0);
+ sseu->eu_mask.xehp[subslice] = eu_mask;
+ } else {
+ eu_mask &= GENMASK(sseu->max_eus_per_subslice - 1, 0);
Is this masking required? Oh I remember.. it's the type expansion! I thought that was wrong. I mean the callers are wrong. Some use u8 for the mask and then do ~mask passing it into u16 here. I don't think this function should account for that but callers should stop passing in garbage.
I had this in my patch:
GEM_WARN_ON(mask && (__fls(mask) >= sseu->max_eus_per_subslice));
And in the callers like:
- sseu_set_eus(sseu, 0, 0, ~disabled_mask);
+ sseu_set_eus(sseu, 0, 0, ~disabled_mask & 0xff);
- sseu_set_eus(sseu, s, ss, ~eu_disabled_mask);
+ sseu_set_eus(sseu, s, ss, ~eu_disabled_mask & eu_mask);
+ sseu->eu_mask.hsw[slice][subslice] = eu_mask;
+ }
}
static u16 compute_eu_total(const struct sseu_dev_info *sseu)
{
- u16 i, total = 0;
+ int s, ss, total = 0;
- for (i = 0; i < ARRAY_SIZE(sseu->eu_mask); i++)
- total += hweight8(sseu->eu_mask[i]);
+ for (s = 0; s < sseu->max_slices; s++)
+ for (ss = 0; ss < sseu->max_subslices; ss++)
+ if (sseu->has_xehp_dss)
+ total += hweight16(sseu->eu_mask.xehp[ss]);
+ else
+ total += hweight16(sseu->eu_mask.hsw[s][ss]);
return total;
}
+/**
+ * intel_sseu_copy_eumask_to_user - Copy EU mask into a userspace buffer
+ * @to: Pointer to userspace buffer to copy to
+ * @sseu: SSEU structure containing EU mask to copy
+ *
+ * Copies the EU mask to a userspace buffer in the format expected by
+ * the query ioctl's topology queries.
+ *
+ * Returns the result of the copy_to_user() operation.
+ */
+int intel_sseu_copy_eumask_to_user(void __user *to,
+ const struct sseu_dev_info *sseu)
+{
+ u8 eu_mask[GEN_SS_MASK_SIZE * GEN_MAX_EU_STRIDE] = {};
+ int len = sseu->max_slices * sseu->max_subslices * sseu->eu_stride;
How compilcated to kick eu_stride out of kernel struct sseu_dev_info and just calculate it here? Since I don't think it belongs in the kernel struct.
What about ss_stride - is that still in use at this point, or by the end of the series, and could it be dropped?
Regards,
Tvrtko
+ int s, ss, i;
+
+ for (s = 0; s < sseu->max_slices; s++) {
+ for (ss = 0; ss < sseu->max_subslices; ss++) {
+ int uapi_offset =
+ s * sseu->max_subslices * sseu->eu_stride +
+ ss * sseu->eu_stride;
+ u16 mask = sseu_get_eus(sseu, s, ss);
+
+ for (i = 0; i < sseu->eu_stride; i++)
+ eu_mask[uapi_offset + i] =
+ (mask >> (BITS_PER_BYTE * i)) & 0xff;
+ }
+ }
+
+ return copy_to_user(to, eu_mask, len);
+}
+
static void gen11_compute_sseu_info(struct sseu_dev_info *sseu,
u32 g_ss_en, u32 c_ss_en, u16 eu_en)
{
diff --git a/drivers/gpu/drm/i915/gt/intel_sseu.h b/drivers/gpu/drm/i915/gt/intel_sseu.h
index 4a041f9dc490..43a8f8f98687 100644
--- a/drivers/gpu/drm/i915/gt/intel_sseu.h
+++ b/drivers/gpu/drm/i915/gt/intel_sseu.h
@@ -57,7 +57,11 @@ struct sseu_dev_info {
u8 subslice_mask[GEN_SS_MASK_SIZE];
u8 geometry_subslice_mask[GEN_SS_MASK_SIZE];
u8 compute_subslice_mask[GEN_SS_MASK_SIZE];
- u8 eu_mask[GEN_SS_MASK_SIZE * GEN_MAX_EU_STRIDE];
+ union {
+ u16 hsw[GEN_MAX_HSW_SLICES][GEN_MAX_SS_PER_HSW_SLICE];
+ u16 xehp[GEN_MAX_DSS];
+ } eu_mask;
+
u16 eu_total;
u8 eu_per_subslice;
u8 min_eu_in_pool;
@@ -150,4 +154,7 @@ void intel_sseu_print_topology(struct drm_i915_private *i915,
u16 intel_slicemask_from_dssmask(u64 dss_mask, int dss_per_slice);
+int intel_sseu_copy_eumask_to_user(void __user *to,
+ const struct sseu_dev_info *sseu);
+
#endif /* __INTEL_SSEU_H__ */
diff --git a/drivers/gpu/drm/i915/i915_query.c b/drivers/gpu/drm/i915/i915_query.c
index 7584cec53d5d..16f43bf32a05 100644
--- a/drivers/gpu/drm/i915/i915_query.c
+++ b/drivers/gpu/drm/i915/i915_query.c
@@ -76,10 +76,10 @@ static int fill_topology_info(const struct sseu_dev_info *sseu,
subslice_mask, subslice_length))
return -EFAULT;
- if (copy_to_user(u64_to_user_ptr(query_item->data_ptr +
- sizeof(topo) +
- slice_length + subslice_length),
- sseu->eu_mask, eu_length))
+ if (intel_sseu_copy_eumask_to_user(u64_to_user_ptr(query_item->data_ptr +
+ sizeof(topo) +
+ slice_length + subslice_length),
+ sseu))
return -EFAULT;
return total_length;
