LGTM Reviewed-by: Nirmoy Das nirmoy.das@intel.com
On 5/25/2022 8:43 PM, Matthew Auld wrote:
If set, force the allocation to be placed in the mappable portion of I915_MEMORY_CLASS_DEVICE. One big restriction here is that system memory (i.e I915_MEMORY_CLASS_SYSTEM) must be given as a potential placement for the object, that way we can always spill the object into system memory if we can't make space.
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: 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
drivers/gpu/drm/i915/gem/i915_gem_create.c | 26 ++++++--- include/uapi/drm/i915_drm.h | 61 +++++++++++++++++++--- 2 files changed, 71 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_create.c b/drivers/gpu/drm/i915/gem/i915_gem_create.c index d094cae0ddf1..33673fe7ee0a 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_create.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_create.c @@ -241,6 +241,7 @@ struct create_ext { struct drm_i915_private *i915; struct intel_memory_region *placements[INTEL_REGION_UNKNOWN]; unsigned int n_placements;
- unsigned int placement_mask; unsigned long flags; };
@@ -337,6 +338,7 @@ static int set_placements(struct drm_i915_gem_create_ext_memory_regions *args, for (i = 0; i < args->num_regions; i++) ext_data->placements[i] = placements[i];
ext_data->placement_mask = mask; return 0;
out_dump:
@@ -411,7 +413,7 @@ i915_gem_create_ext_ioctl(struct drm_device *dev, void *data, struct drm_i915_gem_object *obj; int ret;
- if (args->flags)
if (args->flags & ~I915_GEM_CREATE_EXT_FLAG_NEEDS_CPU_ACCESS) return -EINVAL;
ret = i915_user_extensions(u64_to_user_ptr(args->extensions),
@@ -427,13 +429,21 @@ 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;
if (args->flags & I915_GEM_CREATE_EXT_FLAG_NEEDS_CPU_ACCESS) {
if (ext_data.n_placements == 1)return -EINVAL;/** We always need to be able to spill to system memory, if we* can't place in the mappable part of LMEM.*/if (!(ext_data.placement_mask & BIT(INTEL_REGION_SMEM)))return -EINVAL;} else {
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,
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index e30f31a440b3..5b0a10e6a1b8 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -3366,11 +3366,11 @@ struct drm_i915_query_memory_regions {
- struct drm_i915_gem_create_ext - Existing gem_create behaviour, with added
- extension support using struct i915_user_extension.
- Note that in the future we want to have our buffer flags here, at least for
- the stuff that is immutable. Previously we would have two ioctls, one to
- create the object with gem_create, and another to apply various parameters,
- however this creates some ambiguity for the params which are considered
- immutable. Also in general we're phasing out the various SET/GET ioctls.
- Note that new buffer flags should be added here, at least for the stuff that
- is immutable. Previously we would have two ioctls, one to create the object
- with gem_create, and another to apply various parameters, however this
- creates some ambiguity for the params which are considered immutable. Also in
*/ struct drm_i915_gem_create_ext { /**
- general we're phasing out the various SET/GET ioctls.
@@ -3378,7 +3378,6 @@ struct drm_i915_gem_create_ext { * * The (page-aligned) allocated size for the object will be returned. *
*
- DG2 64K min page size implications:
- On discrete platforms, starting from DG2, we have to contend with GTT
@@ -3390,7 +3389,9 @@ struct drm_i915_gem_create_ext { * * Note that the returned size here will always reflect any required * rounding up done by the kernel, i.e 4K will now become 64K on devices
* such as DG2.
* such as DG2. The kernel will always select the largest minimum* page-size for the set of possible placements as the value to use when* rounding up the @size.
- Special DG2 GTT address alignment requirement:
@@ -3414,14 +3415,58 @@ struct drm_i915_gem_create_ext { * is deemed to be a good compromise. */ __u64 size;
- /**
*/ __u32 handle;
- @handle: Returned handle for the object.
- Object handles are nonzero.
- /** @flags: MBZ */
- /**
* @flags: Optional flags.** Supported values:** I915_GEM_CREATE_EXT_FLAG_NEEDS_CPU_ACCESS - Signal to the kernel that* the object will need to be accessed via the CPU.** Only valid when placing objects in I915_MEMORY_CLASS_DEVICE, and only* strictly required on configurations where some subset of the device* memory is directly visible/mappable through the CPU (which we also* call small BAR), like on some DG2+ systems. Note that this is quite* undesirable, but due to various factors like the client CPU, BIOS etc* it's something we can expect to see in the wild. See* &drm_i915_memory_region_info.probed_cpu_visible_size for how to* determine if this system applies.** Note that one of the placements MUST be I915_MEMORY_CLASS_SYSTEM, to* ensure the kernel can always spill the allocation to system memory,* if the object can't be allocated in the mappable part of* I915_MEMORY_CLASS_DEVICE.** Also note that since the kernel only supports flat-CCS on objects* that can *only* be placed in I915_MEMORY_CLASS_DEVICE, we therefore* don't support I915_GEM_CREATE_EXT_FLAG_NEEDS_CPU_ACCESS together with* flat-CCS.** Without this hint, the kernel will assume that non-mappable* I915_MEMORY_CLASS_DEVICE is preferred for this object. Note that the* kernel can still migrate the object to the mappable part, as a last* resort, if userspace ever CPU faults this object, but this might be* expensive, and so ideally should be avoided.** On older kernels which lack the relevant small-bar uAPI support (see* also &drm_i915_memory_region_info.probed_cpu_visible_size),* usage of the flag will result in an error, but it should NEVER be* possible to end up with a small BAR configuration, assuming we can* also successfully load the i915 kernel module. In such cases the* entire I915_MEMORY_CLASS_DEVICE region will be CPU accessible, and as* such there are zero restrictions on where the object can be placed.*/+#define I915_GEM_CREATE_EXT_FLAG_NEEDS_CPU_ACCESS (1 << 0) __u32 flags;
- /**
- @extensions: The chain of extensions to apply to this object.