[PATCH v2 29/37] drm/i915: Introduce DRM_I915_GEM_MMAP_OFFSET

Matthew Auld
2019-06-27T20:57:23Z

From: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>

Add a new CPU mmap implementation that allows multiple 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.

Signed-off-by: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_ioctls.h | 2 ++
drivers/gpu/drm/i915/gem/i915_gem_mman.c | 30 ++++++++++++++++++
.../gpu/drm/i915/gem/i915_gem_object_types.h | 3 ++
drivers/gpu/drm/i915/i915_drv.c | 3 +-
include/uapi/drm/i915_drm.h | 31 +++++++++++++++++++
5 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ioctls.h b/drivers/gpu/drm/i915/gem/i915_gem_ioctls.h
index ddc7f2a52b3e..5abd5b2172f2 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ioctls.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ioctls.h
@@ -30,6 +30,8 @@ int i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
struct drm_file *file);
int i915_gem_mmap_gtt_ioctl(struct drm_device *dev, void *data,
struct drm_file *file);
+int i915_gem_mmap_offset_ioctl(struct drm_device *dev, void *data,
+ struct drm_file *file_priv);
int i915_gem_pread_ioctl(struct drm_device *dev, void *data,
struct drm_file *file);
int i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index 7b46f44d9c20..cbf89e80a97b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -536,12 +536,42 @@ i915_gem_mmap_gtt_ioctl(struct drm_device *dev, void *data,
struct drm_file *file)
{
struct drm_i915_gem_mmap_offset *args = data;
+ struct drm_i915_private *i915 = to_i915(dev);
+
+ if (args->flags & I915_MMAP_OFFSET_FLAGS)
+ return i915_gem_mmap_offset_ioctl(dev, data, file);
+
+ if (!HAS_MAPPABLE_APERTURE(i915)) {
+ DRM_ERROR("No aperture, cannot mmap via legacy GTT\n");
+ return -ENODEV;
+ }

return __assign_gem_object_mmap_data(file, args->handle,
I915_MMAP_TYPE_GTT,
&args->offset);
}

+int i915_gem_mmap_offset_ioctl(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_WB)) &&
+ !boot_cpu_has(X86_FEATURE_PAT))
+ return -ENODEV;
+
+ if (args->flags & I915_MMAP_OFFSET_WC)
+ type = I915_MMAP_TYPE_OFFSET_WC;
+ else if (args->flags & I915_MMAP_OFFSET_WB)
+ type = I915_MMAP_TYPE_OFFSET_WB;
+ else if (args->flags & I915_MMAP_OFFSET_UC)
+ type = I915_MMAP_TYPE_OFFSET_UC;
+
+ return __assign_gem_object_mmap_data(file, args->handle, type,
+ &args->offset);
+}
+
void i915_mmap_offset_object_release(struct kref *ref)
{
struct i915_mmap_offset *mmo = container_of(ref,
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 86f358da8085..f95e54a25426 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
@@ -63,6 +63,9 @@ struct drm_i915_gem_object_ops {

enum i915_mmap_type {
I915_MMAP_TYPE_GTT = 0,
+ I915_MMAP_TYPE_OFFSET_WC,
+ I915_MMAP_TYPE_OFFSET_WB,
+ I915_MMAP_TYPE_OFFSET_UC,
};

struct i915_mmap_offset {
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 0f1f3b7f3029..8dadd6b9a0a9 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -459,6 +459,7 @@ static int i915_getparam_ioctl(struct drm_device *dev, void *data,
case I915_PARAM_HAS_EXEC_BATCH_FIRST:
case I915_PARAM_HAS_EXEC_FENCE_ARRAY:
case I915_PARAM_HAS_EXEC_SUBMIT_FENCE:
+ case I915_PARAM_MMAP_OFFSET_VERSION:
/* For the time being all of these are always true;
* if some supported hardware does not have one of these
* features this value needs to be provided from
@@ -3176,7 +3177,7 @@ static const struct drm_ioctl_desc i915_ioctls[] = {
DRM_IOCTL_DEF_DRV(I915_GEM_PREAD, i915_gem_pread_ioctl, DRM_RENDER_ALLOW),
DRM_IOCTL_DEF_DRV(I915_GEM_PWRITE, i915_gem_pwrite_ioctl, DRM_RENDER_ALLOW),
DRM_IOCTL_DEF_DRV(I915_GEM_MMAP, i915_gem_mmap_ioctl, DRM_RENDER_ALLOW),
- DRM_IOCTL_DEF_DRV(I915_GEM_MMAP_GTT, i915_gem_mmap_gtt_ioctl, DRM_RENDER_ALLOW),
+ DRM_IOCTL_DEF_DRV(I915_GEM_MMAP_OFFSET, i915_gem_mmap_gtt_ioctl, DRM_RENDER_ALLOW),
DRM_IOCTL_DEF_DRV(I915_GEM_SET_DOMAIN, i915_gem_set_domain_ioctl, DRM_RENDER_ALLOW),
DRM_IOCTL_DEF_DRV(I915_GEM_SW_FINISH, i915_gem_sw_finish_ioctl, DRM_RENDER_ALLOW),
DRM_IOCTL_DEF_DRV(I915_GEM_SET_TILING, i915_gem_set_tiling_ioctl, DRM_RENDER_ALLOW),
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 328d05e77d9f..729e729e2282 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -359,6 +359,7 @@ typedef struct _drm_i915_sarea {
#define DRM_I915_QUERY 0x39
#define DRM_I915_GEM_VM_CREATE 0x3a
#define DRM_I915_GEM_VM_DESTROY 0x3b
+#define DRM_I915_GEM_MMAP_OFFSET DRM_I915_GEM_MMAP_GTT
/* Must be kept compact -- no holes */

#define DRM_IOCTL_I915_INIT DRM_IOW( DRM_COMMAND_BASE + DRM_I915_INIT, drm_i915_init_t)
@@ -421,6 +422,7 @@ typedef struct _drm_i915_sarea {
#define DRM_IOCTL_I915_QUERY DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_QUERY, struct drm_i915_query)
#define DRM_IOCTL_I915_GEM_VM_CREATE DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_VM_CREATE, struct drm_i915_gem_vm_control)
#define DRM_IOCTL_I915_GEM_VM_DESTROY DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_VM_DESTROY, struct drm_i915_gem_vm_control)
+#define DRM_IOCTL_I915_GEM_MMAP_OFFSET DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_MMAP_OFFSET, struct drm_i915_gem_mmap_offset)

/* Allow drivers to submit batchbuffers directly to hardware, relying
* on the security mechanisms provided by hardware.
@@ -610,6 +612,10 @@ typedef struct drm_i915_irq_wait {
* See I915_EXEC_FENCE_OUT and I915_EXEC_FENCE_SUBMIT.
*/
#define I915_PARAM_HAS_EXEC_SUBMIT_FENCE 53
+
+/* Mmap offset ioctl */
+#define I915_PARAM_MMAP_OFFSET_VERSION 54
+
/* Must be kept compact -- no holes and well documented */

typedef struct drm_i915_getparam {
@@ -785,6 +791,31 @@ 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 _WC/_WB flags
+ * should be passed here.
+ */
+ __u64 flags;
+#define I915_MMAP_OFFSET_WC (1 << 0)
+#define I915_MMAP_OFFSET_WB (1 << 1)
+#define I915_MMAP_OFFSET_UC (1 << 2)
+#define I915_MMAP_OFFSET_FLAGS \
+ (I915_MMAP_OFFSET_WC | I915_MMAP_OFFSET_WB | I915_MMAP_OFFSET_UC)
+};
+
struct drm_i915_gem_set_domain {
/** Handle for the object */
__u32 handle;
--
2.20.1