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drm/i915/userptr: Enable read-only support on gen8+

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On gen8 and onwards, we can mark GPU accesses through the ppGTT as being
read-only, that is cause any GPU write onto that page to be discarded
(not triggering a fault). This is all that we need to finally support
the read-only flag for userptr!

v2: Check default address space for read only support as a proxy for the
user context/ppgtt.

Testcase: igt/gem_userptr_blits/readonly*
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.william.auld@gmail.com>
Reviewed-by: Jon Bloomfield <jon.bloomfield@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180712191430.9269-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2018-07-12 20:14:30 +01:00
parent f8c1cce36c
commit 0b100760e3
2 changed files with 12 additions and 7 deletions
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1
drivers/gpu/drm/i915/i915_gem_object.h
View File

@ -267,7 +267,6 @@ struct drm_i915_gem_object {
union {
struct i915_gem_userptr {
uintptr_t ptr;
unsigned read_only :1;
struct i915_mm_struct *mm;
struct i915_mmu_object *mmu_object;

18
drivers/gpu/drm/i915/i915_gem_userptr.c
View File

@ -507,7 +507,7 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work)
struct mm_struct *mm = obj->userptr.mm->mm;
unsigned int flags = 0;
if (!obj->userptr.read_only)
if (!i915_gem_object_is_readonly(obj))
flags |= FOLL_WRITE;
ret = -EFAULT;
@ -643,7 +643,7 @@ static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
if (pvec) /* defer to worker if malloc fails */
pinned = __get_user_pages_fast(obj->userptr.ptr,
num_pages,
!obj->userptr.read_only,
!i915_gem_object_is_readonly(obj),
pvec);
}
@ -789,10 +789,15 @@ i915_gem_userptr_ioctl(struct drm_device *dev,
return -EFAULT;
if (args->flags & I915_USERPTR_READ_ONLY) {
/* On almost all of the current hw, we cannot tell the GPU that a
* page is readonly, so this is just a placeholder in the uAPI.
struct i915_hw_ppgtt *ppgtt;
/*
* On almost all of the older hw, we cannot tell the GPU that
* a page is readonly.
*/
return -ENODEV;
ppgtt = dev_priv->kernel_context->ppgtt;
if (!ppgtt || !ppgtt->vm.has_read_only)
return -ENODEV;
}
obj = i915_gem_object_alloc(dev_priv);
@ -806,7 +811,8 @@ i915_gem_userptr_ioctl(struct drm_device *dev,
i915_gem_object_set_cache_coherency(obj, I915_CACHE_LLC);
obj->userptr.ptr = args->user_ptr;
obj->userptr.read_only = !!(args->flags & I915_USERPTR_READ_ONLY);
if (args->flags & I915_USERPTR_READ_ONLY)
i915_gem_object_set_readonly(obj);
/* And keep a pointer to the current->mm for resolving the user pages
* at binding. This means that we need to hook into the mmu_notifier