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authorChris Wilson <chris@chris-wilson.co.uk>2021-07-23 14:34:05 +0300
committerMaarten Lankhorst <maarten.lankhorst@linux.intel.com>2021-08-05 12:34:00 +0300
commitb65a9489730a2494f7a2a33a6eb0a12b8f1dd193 (patch)
treed29dab798da9c92501a26ea5645af29f0ea22a96 /include/uapi/drm
parent8e02cceb1f1f4f254625e5338dd997ff61ab40d7 (diff)
downloadlinux-b65a9489730a2494f7a2a33a6eb0a12b8f1dd193.tar.xz
drm/i915/userptr: Probe existence of backing struct pages upon creation
Jason Ekstrand requested a more efficient method than userptr+set-domain to determine if the userptr object was backed by a complete set of pages upon creation. To be more efficient than simply populating the userptr using get_user_pages() (as done by the call to set-domain or execbuf), we can walk the tree of vm_area_struct and check for gaps or vma not backed by struct page (VM_PFNMAP). The question is how to handle VM_MIXEDMAP which may be either struct page or pfn backed... With discrete we are going to drop support for set_domain(), so offering a way to probe the pages, without having to resort to dummy batches has been requested. v2: - add new query param for the PROBE flag, so userspace can easily check if the kernel supports it(Jason). - use mmap_read_{lock, unlock}. - add some kernel-doc. v3: - In the docs also mention that PROBE doesn't guarantee that the pages will remain valid by the time they are actually used(Tvrtko). - Add a small comment for the hole finding logic(Jason). - Move the param next to all the other params which just return true. Testcase: igt/gem_userptr_blits/probe Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Matthew Auld <matthew.auld@intel.com> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Kenneth Graunke <kenneth@whitecape.org> Cc: Jason Ekstrand <jason@jlekstrand.net> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Ramalingam C <ramalingam.c@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Acked-by: Kenneth Graunke <kenneth@whitecape.org> Reviewed-by: Jason Ekstrand <jason@jlekstrand.net> Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20210723113405.427004-1-matthew.auld@intel.com
Diffstat (limited to 'include/uapi/drm')
-rw-r--r--include/uapi/drm/i915_drm.h20
1 files changed, 20 insertions, 0 deletions
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 7f13d241417f..bde5860b3686 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -683,6 +683,9 @@ typedef struct drm_i915_irq_wait {
*/
#define I915_PARAM_HAS_EXEC_TIMELINE_FENCES 55
+/* Query if the kernel supports the I915_USERPTR_PROBE flag. */
+#define I915_PARAM_HAS_USERPTR_PROBE 56
+
/* Must be kept compact -- no holes and well documented */
typedef struct drm_i915_getparam {
@@ -2231,12 +2234,29 @@ struct drm_i915_gem_userptr {
* through the GTT. If the HW can't support readonly access, an error is
* returned.
*
+ * I915_USERPTR_PROBE:
+ *
+ * Probe the provided @user_ptr range and validate that the @user_ptr is
+ * indeed pointing to normal memory and that the range is also valid.
+ * For example if some garbage address is given to the kernel, then this
+ * should complain.
+ *
+ * Returns -EFAULT if the probe failed.
+ *
+ * Note that this doesn't populate the backing pages, and also doesn't
+ * guarantee that the object will remain valid when the object is
+ * eventually used.
+ *
+ * The kernel supports this feature if I915_PARAM_HAS_USERPTR_PROBE
+ * returns a non-zero value.
+ *
* I915_USERPTR_UNSYNCHRONIZED:
*
* NOT USED. Setting this flag will result in an error.
*/
__u32 flags;
#define I915_USERPTR_READ_ONLY 0x1
+#define I915_USERPTR_PROBE 0x2
#define I915_USERPTR_UNSYNCHRONIZED 0x80000000
/**
* @handle: Returned handle for the object.