[PATCH 3/5] drm/i915: Introduce DRM_I915_GEM_MMAP_OFFSET
Abdiel Janulgue
abdiel.janulgue at linux.intel.com
Tue Oct 15 07:48:45 UTC 2019
This is really just an alias of mmap_gtt. The 'mmap offset' nomenclature
comes the value returned by this ioctl which is the offset into the
device fd which userpace uses with mmap(2).
mmap_gtt was our initial mmap_offset implementation, this extends
our CPU mmap support to allow additional fault handlers that depends on
the object's backing pages.
Note that we multiplex mmap_gtt and mmap_offset through the same ioctl,
and use the zero extending behaviour of drm to differentiate between
them, when we inspect the flags.
v2:
- Drop the alias, just rename the struct (Chris)
- Don't bail out on no PAT when doing WB mmaps
- Prepare uAPI for further extensions
Signed-off-by: Abdiel Janulgue <abdiel.janulgue at linux.intel.com>
Signed-off-by: Matthew Auld <matthew.auld at intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_mman.c | 36 +++++++++++++++++--
.../gpu/drm/i915/gem/i915_gem_object_types.h | 3 ++
include/uapi/drm/i915_drm.h | 30 +++++++++++++++-
3 files changed, 66 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index 4fb46cbf1bcc..763f3bd78e65 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -144,6 +144,9 @@ static unsigned int tile_row_pages(const struct drm_i915_gem_object *obj)
* 3 - Remove implicit set-domain(GTT) and synchronisation on initial
* pagefault; swapin remains transparent.
*
+ * 4 - Support multiple fault handlers per object depending on object's
+ * backing storage (a.k.a. MMAP_OFFSET).
+ *
* Restrictions:
*
* * snoopable objects cannot be accessed via the GTT. It can cause machine
@@ -171,7 +174,7 @@ static unsigned int tile_row_pages(const struct drm_i915_gem_object *obj)
*/
int i915_gem_mmap_gtt_version(void)
{
- return 3;
+ return 4;
}
static inline struct i915_ggtt_view
@@ -539,6 +542,27 @@ __assign_gem_object_mmap_data(struct drm_file *file,
return ret;
}
+static int gem_mmap_offset(struct drm_device *dev, void *data,
+ struct drm_file *file)
+{
+ struct drm_i915_gem_mmap_offset *args = data;
+ enum i915_mmap_type type;
+
+ if ((args->flags & (I915_MMAP_OFFSET_WC | I915_MMAP_OFFSET_UC)) &&
+ !boot_cpu_has(X86_FEATURE_PAT))
+ return -ENODEV;
+
+ if (args->flags & I915_MMAP_OFFSET_WC)
+ type = I915_MMAP_TYPE_WC;
+ else if (args->flags & I915_MMAP_OFFSET_WB)
+ type = I915_MMAP_TYPE_WB;
+ else if (args->flags & I915_MMAP_OFFSET_UC)
+ type = I915_MMAP_TYPE_UC;
+
+ return __assign_gem_object_mmap_data(file, args->handle, type,
+ &args->offset);
+}
+
/**
* i915_gem_mmap_gtt_ioctl - prepare an object for GTT mmap'ing
* @dev: DRM device
@@ -558,7 +582,15 @@ int
i915_gem_mmap_gtt_ioctl(struct drm_device *dev, void *data,
struct drm_file *file)
{
- struct drm_i915_gem_mmap_gtt *args = data;
+ struct drm_i915_gem_mmap_offset *args = data;
+ struct drm_i915_private *i915 = to_i915(dev);
+
+ if (args->flags & I915_MMAP_OFFSET_FLAGS)
+ return gem_mmap_offset(dev, data, file);
+
+ if (!HAS_MAPPABLE_APERTURE(i915))
+ /* No aperture, cannot mmap via legacy GTT */
+ return -ENODEV;
return __assign_gem_object_mmap_data(file, args->handle,
I915_MMAP_TYPE_GTT,
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
index c5c305bd9927..c643d45f5c0d 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
@@ -64,6 +64,9 @@ struct drm_i915_gem_object_ops {
enum i915_mmap_type {
I915_MMAP_TYPE_GTT = 0,
+ I915_MMAP_TYPE_WC,
+ I915_MMAP_TYPE_WB,
+ I915_MMAP_TYPE_UC,
};
struct i915_mmap_offset {
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 63d40cba97e0..b4b017ca3463 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -394,7 +394,7 @@ typedef struct _drm_i915_sarea {
#define DRM_IOCTL_I915_GEM_PREAD DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_PREAD, struct drm_i915_gem_pread)
#define DRM_IOCTL_I915_GEM_PWRITE DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_PWRITE, struct drm_i915_gem_pwrite)
#define DRM_IOCTL_I915_GEM_MMAP DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_MMAP, struct drm_i915_gem_mmap)
-#define DRM_IOCTL_I915_GEM_MMAP_GTT DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_MMAP_GTT, struct drm_i915_gem_mmap_gtt)
+#define DRM_IOCTL_I915_GEM_MMAP_GTT DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_MMAP_GTT, struct drm_i915_gem_mmap_offset)
#define DRM_IOCTL_I915_GEM_SET_DOMAIN DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_SET_DOMAIN, struct drm_i915_gem_set_domain)
#define DRM_IOCTL_I915_GEM_SW_FINISH DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_SW_FINISH, struct drm_i915_gem_sw_finish)
#define DRM_IOCTL_I915_GEM_SET_TILING DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_SET_TILING, struct drm_i915_gem_set_tiling)
@@ -793,6 +793,34 @@ struct drm_i915_gem_mmap_gtt {
__u64 offset;
};
+struct drm_i915_gem_mmap_offset {
+ /** Handle for the object being mapped. */
+ __u32 handle;
+ __u32 pad;
+ /**
+ * Fake offset to use for subsequent mmap call
+ *
+ * This is a fixed-size type for 32/64 compatibility.
+ */
+ __u64 offset;
+
+ /**
+ * Flags for extended behaviour.
+ *
+ * It is mandatory that either one of the MMAP_OFFSET flags
+ * should be passed here.
+ */
+ __u64 flags;
+#define I915_MMAP_OFFSET_EXTENSION (1u << 0)
+#define I915_MMAP_OFFSET_WC (1u << 1)
+#define I915_MMAP_OFFSET_WB (1u << 2)
+#define I915_MMAP_OFFSET_UC (1u << 3)
+#define I915_MMAP_OFFSET_FLAGS \
+ (I915_MMAP_OFFSET_EXTENSION | I915_MMAP_OFFSET_WC | \
+ I915_MMAP_OFFSET_WB | I915_MMAP_OFFSET_UC )
+ __u64 extensions;
+};
+
struct drm_i915_gem_set_domain {
/** Handle for the object */
__u32 handle;
--
2.23.0
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