[PATCH 01/03] drm/i915: add a context parameter to {en, dis}able zero address mapping

David Weinehall
2015-05-20T14:01:45Z

Export a new context parameter that can be set/queried through the
context_{get,set}param ioctls. This parameter is passed as a context
flag and decides whether or not a GPU address mapping is allowed to
be made at address zero. The default is to allow such mappings.

Signed-off-by: David Weinehall <david.weinehall@intel.com>
---
drivers/gpu/drm/i915/i915_drv.h | 5 +++++
drivers/gpu/drm/i915/i915_gem_context.c | 11 +++++++++++
drivers/gpu/drm/i915/i915_gem_execbuffer.c | 13 +++++++++----
include/uapi/drm/i915_drm.h | 1 +
4 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index acfa4fc93803..421640a53dd8 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -781,11 +781,15 @@ struct i915_ctx_hang_stats {

/* This must match up with the value previously used for execbuf2.rsvd1. */
#define DEFAULT_CONTEXT_HANDLE 0
+
+#define CONTEXT_NO_ZEROMAP (1<<0)
/**
* struct intel_context - as the name implies, represents a context.
* @ref: reference count.
* @user_handle: userspace tracking identity for this context.
* @remap_slice: l3 row remapping information.
+ * @flags: context specific flags:
+ * CONTEXT_NO_ZEROMAP: do not allow mapping things to page 0.
* @file_priv: filp associated with this context (NULL for global default
* context).
* @hang_stats: information about the role of this context in possible GPU
@@ -802,6 +806,7 @@ struct intel_context {
struct kref ref;
int user_handle;
uint8_t remap_slice;
+ int flags;
struct drm_i915_file_private *file_priv;
struct i915_ctx_hang_stats hang_stats;
struct i915_hw_ppgtt *ppgtt;
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 5a47eb5e3c5d..10bd0cfe34ad 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -902,6 +902,9 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
case I915_CONTEXT_PARAM_BAN_PERIOD:
args->value = ctx->hang_stats.ban_period_seconds;
break;
+ case I915_CONTEXT_PARAM_NO_ZEROMAP:
+ args->value = ctx->flags & CONTEXT_NO_ZEROMAP;
+ break;
default:
ret = -EINVAL;
break;
@@ -939,6 +942,14 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
else
ctx->hang_stats.ban_period_seconds = args->value;
break;
+ case I915_CONTEXT_PARAM_NO_ZEROMAP:
+ if (args->size) {
+ ret = -EINVAL;
+ } else {
+ ctx->flags &= ~CONTEXT_NO_ZEROMAP;
+ ctx->flags |= args->value ? CONTEXT_NO_ZEROMAP : 0;
+ }
+ break;
default:
ret = -EINVAL;
break;
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 560c79a8a43d..6cfc716d7186 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -676,6 +676,7 @@ eb_vma_misplaced(struct i915_vma *vma)
static int
i915_gem_execbuffer_reserve(struct intel_engine_cs *ring,
struct list_head *vmas,
+ struct intel_context *ctx,
bool *need_relocs)
{
struct drm_i915_gem_object *obj;
@@ -698,6 +699,9 @@ i915_gem_execbuffer_reserve(struct intel_engine_cs *ring,
obj = vma->obj;
entry = vma->exec_entry;

+ if (ctx->flags & CONTEXT_NO_ZEROMAP)
+ entry->flags |= __EXEC_OBJECT_NEEDS_BIAS;
+
if (!has_fenced_gpu_access)
entry->flags &= ~EXEC_OBJECT_NEEDS_FENCE;
need_fence =
@@ -775,7 +779,8 @@ i915_gem_execbuffer_relocate_slow(struct drm_device *dev,
struct drm_file *file,
struct intel_engine_cs *ring,
struct eb_vmas *eb,
- struct drm_i915_gem_exec_object2 *exec)
+ struct drm_i915_gem_exec_object2 *exec,
+ struct intel_context *ctx)
{
struct drm_i915_gem_relocation_entry *reloc;
struct i915_address_space *vm;
@@ -861,7 +866,7 @@ i915_gem_execbuffer_relocate_slow(struct drm_device *dev,
goto err;

need_relocs = (args->flags & I915_EXEC_NO_RELOC) == 0;
- ret = i915_gem_execbuffer_reserve(ring, &eb->vmas, &need_relocs);
+ ret = i915_gem_execbuffer_reserve(ring, &eb->vmas, ctx, &need_relocs);
if (ret)
goto err;

@@ -1515,7 +1520,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,

/* Move the objects en-masse into the GTT, evicting if necessary. */
need_relocs = (args->flags & I915_EXEC_NO_RELOC) == 0;
- ret = i915_gem_execbuffer_reserve(ring, &eb->vmas, &need_relocs);
+ ret = i915_gem_execbuffer_reserve(ring, &eb->vmas, ctx, &need_relocs);
if (ret)
goto err;

@@ -1525,7 +1530,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
if (ret) {
if (ret == -EFAULT) {
ret = i915_gem_execbuffer_relocate_slow(dev, args, file, ring,
- eb, exec);
+ eb, exec, ctx);
BUG_ON(!mutex_is_locked(&dev->struct_mutex));
}
if (ret)
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 4851d660243c..5ae2b0f98999 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1102,6 +1102,7 @@ struct drm_i915_gem_context_param {
__u32 size;
__u64 param;
#define I915_CONTEXT_PARAM_BAN_PERIOD 0x1
+#define I915_CONTEXT_PARAM_NO_ZEROMAP 0x2
__u64 value;
};