gpu: nvgpu: support userspace vidmem mappings

When mapping a userspace buffer, determine if it was vidmem allocated
from the aperture of the current gpu, and pass that information into
page tables.

Mapping a vidmem buffer to a gpu it wasn't allocated from is disallowed.
This includes mapping vidmem to igpus and to possibly other dgpus on the
system.

Jira DNVGPU-19

Change-Id: Ia9d2d0133e77659ab96b36ed61eeb4cd5a2b7dff
Signed-off-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-on: http://git-master/r/1169309
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Vijayakumar Subbu <vsubbu@nvidia.com>

1 files changed, 35 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/mm_gk20a.c b/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
index 2dcc4363..1d32a41f 100644
--- a/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
@@ -1935,6 +1935,20 @@ static struct dma_buf *gk20a_vidbuf_export(struct gk20a_vidmem_buf *buf)
 }
 #endif
 
+static struct gk20a *gk20a_vidmem_buf_owner(struct dma_buf *dmabuf)
+{
+#if defined(CONFIG_GK20A_VIDMEM)
+        struct gk20a_vidmem_buf *buf = dmabuf->priv;
+
+        if (dmabuf->ops != &gk20a_vidbuf_ops)
+                return NULL;
+
+        return buf->g;
+#else
+        return NULL;
+#endif
+}
+
 int gk20a_vidmem_buf_alloc(struct gk20a *g, size_t bytes)
 {
 #if defined(CONFIG_GK20A_VIDMEM)
@@ -2010,6 +2024,8 @@ u64 gk20a_vm_map(struct vm_gk20a *vm,
         u32 ctag_map_win_ctagline = 0;
         struct vm_reserved_va_node *va_node = NULL;
         u32 ctag_offset;
+        struct gk20a *buf_owner;
+        enum gk20a_aperture aperture;
 
         if (user_mapped && vm->userspace_managed &&
             !(flags & NVGPU_AS_MAP_BUFFER_FLAGS_FIXED_OFFSET)) {
@@ -2185,6 +2201,24 @@ u64 gk20a_vm_map(struct vm_gk20a *vm,
                 ctag_offset += buffer_offset >>
                                ilog2(g->ops.fb.compression_page_size(g));
 
+        buf_owner = gk20a_vidmem_buf_owner(dmabuf);
+        if (buf_owner == NULL) {
+                /* Not nvgpu-allocated, assume system memory */
+                aperture = APERTURE_SYSMEM;
+        } else if (WARN_ON(buf_owner == g && !g->mm.vidmem_is_vidmem)) {
+                /* Looks like our video memory, but this gpu doesn't support
+                 * it. Warn about a bug and bail out */
+                err = -EINVAL;
+                goto clean_up;
+        } else if (buf_owner != g) {
+                /* Someone else's vidmem */
+                err = -EINVAL;
+                goto clean_up;
+        } else {
+                /* Yay, buf_owner == g */
+                aperture = APERTURE_VIDMEM;
+        }
+
         /* update gmmu ptes */
         map_offset = g->ops.mm.gmmu_map(vm, map_offset,
                                         bfr.sgt,
@@ -2198,7 +2232,7 @@ u64 gk20a_vm_map(struct vm_gk20a *vm,
                                         false,
                                         false,
                                         batch,
-                                        APERTURE_SYSMEM); /* no vidmem yet */
+                                        aperture);
         if (!map_offset)
                 goto clean_up;