From 672c6af6850a4be7fcde67246574b268b9e9dd71 Mon Sep 17 00:00:00 2001
From: Matthew Auld <matthew.auld@intel.com>
Date: Wed, 29 Jun 2022 18:43:42 +0100
Subject: drm/i915/uapi: apply ALLOC_GPU_ONLY by default
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Git-commit: 1dbd07e088673dbf0e10f4bcfa17f971fd870195
Patch-mainline: v6.0-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225 jsc#PED-2849
On small BAR configurations, when dealing with I915_MEMORY_CLASS_DEVICE
allocations, we assume that by default, all userspace allocations should
be placed in the non-CPU visible portion. Note that dumb buffers are
not included here, since these are not "GPU accelerated" and likely need
CPU access. We choose to just always set GPU_ONLY, and let the backend
figure out if that should be ignored or not, for example on full BAR
systems.
In a later patch userspace will be able to provide a hint if CPU access
to the buffer is needed.
v2(Thomas)
- Apply GPU_ONLY on all discrete devices, but only if the BO can be
placed in LMEM. Down in the depths this should be turned into a noop,
where required, and as an annotation it still make some sense. If we
apply it regardless of the placements then we end up needing to check
the placements during exec capture. Also it's slightly inconsistent
since the NEEDS_CPU_ACCESS can only be applied on objects that can be
placed in LMEM. The other annoyance would be gem_create_ext vs plain
gem_create, if we were to always apply GPU_ONLY.
Testcase: igt@gem-create@create-ext-cpu-access-sanity-check
Testcase: igt@gem-create@create-ext-cpu-access-big
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Kenneth Graunke <kenneth@whitecape.org>
Cc: Akeem G Abodunrin <akeem.g.abodunrin@intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220629174350.384910-5-matthew.auld@intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/gem/i915_gem_create.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_create.c b/drivers/gpu/drm/i915/gem/i915_gem_create.c
index 5802692ea604..d094cae0ddf1 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_create.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_create.c
@@ -427,6 +427,14 @@ i915_gem_create_ext_ioctl(struct drm_device *dev, void *data,
ext_data.n_placements = 1;
}
+ /*
+ * TODO: add a userspace hint to force CPU_ACCESS for the object, which
+ * can override this.
+ */
+ if (ext_data.n_placements > 1 ||
+ ext_data.placements[0]->type != INTEL_MEMORY_SYSTEM)
+ ext_data.flags |= I915_BO_ALLOC_GPU_ONLY;
+
obj = __i915_gem_object_create_user_ext(i915, args->size,
ext_data.placements,
ext_data.n_placements,
--
2.38.1