gpu: nvgpu: User-space managed address space support

Implement NVGPU_GPU_IOCTL_ALLOC_AS_FLAGS_USERSPACE_MANAGED, which
enables creating userspace-managed GPU address spaces.

When an address space is marked as userspace-managed, the following
changes are in effect:

- Only fixed-address mappings are allowed.
- VA space allocation for fixed-address mappings is not required,
  except to mark space as sparse.
- Maps and unmaps are always immediate. In particular, the mapping
  ref increments at kickoffs and decrements at job completion are
  skipped.

Bug 1614735
Bug 1623949
Bug 1660392

Change-Id: I834fe19b3f65e9b02c268952383eddee0e465759
Signed-off-by: Sami Kiminki <skiminki@nvidia.com>
Reviewed-on: http://git-master/r/738558
Reviewed-on: http://git-master/r/833253
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/vgpu/mm_vgpu.c b/drivers/gpu/nvgpu/vgpu/mm_vgpu.c
index c36b135c..bfaacff5 100644
--- a/drivers/gpu/nvgpu/vgpu/mm_vgpu.c
+++ b/drivers/gpu/nvgpu/vgpu/mm_vgpu.c
@@ -267,7 +267,7 @@ u64 vgpu_bar1_map(struct gk20a *g, struct sg_table **sgt, u64 size)
 
 /* address space interfaces for the gk20a module */
 static int vgpu_vm_alloc_share(struct gk20a_as_share *as_share,
-                u32 big_page_size)
+                               u32 big_page_size, u32 flags)
 {
         struct gk20a_as *as = as_share->as;
         struct gk20a *g = gk20a_from_as(as);
@@ -280,6 +280,8 @@ static int vgpu_vm_alloc_share(struct gk20a_as_share *as_share,
                 kernel_vma_start, kernel_vma_limit;
         char name[32];
         int err, i;
+        const bool userspace_managed =
+                (flags & NVGPU_GPU_IOCTL_ALLOC_AS_FLAGS_USERSPACE_MANAGED) != 0;
 
         /* note: keep the page sizes sorted lowest to highest here */
         u32 gmmu_page_sizes[gmmu_nr_page_sizes] = {
@@ -290,6 +292,12 @@ static int vgpu_vm_alloc_share(struct gk20a_as_share *as_share,
 
         gk20a_dbg_fn("");
 
+        if (userspace_managed) {
+                gk20a_err(dev_from_gk20a(g),
+                          "userspace-managed address spaces not yet supported");
+                return -ENOSYS;
+        }
+
         big_page_size = gmmu_page_sizes[gmmu_page_size_big];
 
         vm = kzalloc(sizeof(*vm), GFP_KERNEL);