gpu: nvgpu: Unify the small and large page address spaces

The basic structure of this patch is to make the small page allocator
and the large page allocator into pointers (where they used to be just
structs). Then assign each of those pointers to the same actual
allocator since the buddy allocator has supported mixed page sizes
since its inception.

For the rest of the driver some changes had to be made in order to
actually support mixed pages in a single address space.

1. Unifying the allocation page size determination

   Since the allocation and map operations happen at distinct
   times both mapping and allocation of GVA space must agree
   on page size. This is because the allocation has to separate
   allocations into separate PDEs to avoid the necessity of
   supporting mixed PDEs.

   To this end a function __get_pte_size() was introduced which
   is used both by the balloc code and the core GPU MM code. It
   determines page size based only on the length of the mapping/
   allocation.

2. Fixed address allocation + page size

   Similar to regular mappings/GVA allocations fixed address
   mapping page size determination had to be modified. In the
   past the address of the mapping determined page size since
   the address space split was by address (low addresses were
   small pages, high addresses large pages). Since that is no
   longer the case the page size field in the reserve memory
   ioctl is now honored by the mapping code. When, for instance,
   CUDA makes a memory reservation it specifies small or large
   pages. When CUDA requests mappings to be made within that
   address range the page size is then looked up in the reserved
   memory struct.

   Fixed address reservations were also modified to now always
   allocate at a PDE granularity (64M or 128M depending on
   large page size. This prevents non-fixed allocations from
   ending up in the same PDE and causing kernel panics or GMMU
   faults.

3. The rest...

   The rest of the changes are just by products of the above.
   Lots of places required minor updates to use a pointer to
   the GVA allocator struct instead of the struct itself.

Lastly, this change is not truly complete. More work remains to be
done in order to fully remove the notion that there was such a thing
as separate address spaces for different page sizes. Basically after
this patch what remains is cleanup and proper documentation.

Bug 1396644
Bug 1729947

Change-Id: If51ab396a37ba16c69e434adb47edeef083dce57
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: http://git-master/r/1265300
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 168 insertions, 114 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/mm_gk20a.c b/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
index cdbaef79..83bbcb54 100644
--- a/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
@@ -1001,7 +1001,8 @@ int gk20a_init_mm_setup_sw(struct gk20a *g)
         mutex_init(&mm->l2_op_lock);
 
         /*TBD: make channel vm size configurable */
-        mm->channel.user_size = NV_MM_DEFAULT_USER_SIZE;
+        mm->channel.user_size = NV_MM_DEFAULT_USER_SIZE -
+                NV_MM_DEFAULT_KERNEL_SIZE;
         mm->channel.kernel_size = NV_MM_DEFAULT_KERNEL_SIZE;
 
         gk20a_dbg_info("channel vm size: user %dMB  kernel %dMB",
@@ -1626,7 +1627,7 @@ u64 gk20a_vm_alloc_va(struct vm_gk20a *vm,
                       enum gmmu_pgsz_gk20a gmmu_pgsz_idx)
 
 {
-        struct nvgpu_allocator *vma = &vm->vma[gmmu_pgsz_idx];
+        struct nvgpu_allocator *vma = vm->vma[gmmu_pgsz_idx];
         u64 offset;
         u64 gmmu_page_size = vm->gmmu_page_sizes[gmmu_pgsz_idx];
 
@@ -1663,7 +1664,7 @@ int gk20a_vm_free_va(struct vm_gk20a *vm,
                      u64 offset, u64 size,
                      enum gmmu_pgsz_gk20a pgsz_idx)
 {
-        struct nvgpu_allocator *vma = &vm->vma[pgsz_idx];
+        struct nvgpu_allocator *vma = vm->vma[pgsz_idx];
 
         gk20a_dbg_info("%s free addr=0x%llx, size=0x%llx",
                         vma->name, offset, size);
@@ -1790,13 +1791,7 @@ struct buffer_attrs {
 static void gmmu_select_page_size(struct vm_gk20a *vm,
                                   struct buffer_attrs *bfr)
 {
-        int i;
-        /*  choose the biggest first (top->bottom) */
-        for (i = gmmu_page_size_kernel - 1; i >= 0; i--)
-                if (!((vm->gmmu_page_sizes[i] - 1) & bfr->align)) {
-                        bfr->pgsz_idx = i;
-                        break;
-                }
+        bfr->pgsz_idx = __get_pte_size(vm, 0, bfr->size);
 }
 
 static int setup_buffer_kind_and_compression(struct vm_gk20a *vm,
@@ -2497,9 +2492,7 @@ u64 gk20a_vm_map(struct vm_gk20a *vm,
          * the alignment determined by gmmu_select_page_size().
          */
         if (flags & NVGPU_AS_MAP_BUFFER_FLAGS_FIXED_OFFSET) {
-                int pgsz_idx =
-                        __nv_gmmu_va_is_big_page_region(vm, offset_align) ?
-                        gmmu_page_size_big : gmmu_page_size_small;
+                int pgsz_idx = __get_pte_size(vm, offset_align, mapping_size);
                 if (pgsz_idx > bfr.pgsz_idx) {
                         gk20a_err(d, "%llx buffer pgsz %d, VA pgsz %d",
                                   offset_align, bfr.pgsz_idx, pgsz_idx);
@@ -3149,7 +3142,7 @@ static u64 __gk20a_gmmu_alloc(struct nvgpu_allocator *allocator, dma_addr_t at,
         u64 addr = 0;
 
         if (at)
-                addr = nvgpu_alloc_fixed(allocator, at, size);
+                addr = nvgpu_alloc_fixed(allocator, at, size, 0);
         else
                 addr = nvgpu_alloc(allocator, size);
 
@@ -4260,12 +4253,13 @@ static int gk20a_init_sema_pool(struct vm_gk20a *vm)
          *
          * !!! TODO: cleanup.
          */
-        sema_sea->gpu_va = nvgpu_alloc_fixed(&vm->vma[gmmu_page_size_kernel],
+        sema_sea->gpu_va = nvgpu_alloc_fixed(&vm->kernel,
                                              vm->va_limit -
                                              mm->channel.kernel_size,
-                                             512 * PAGE_SIZE);
+                                             512 * PAGE_SIZE,
+                                             SZ_4K);
         if (!sema_sea->gpu_va) {
-                nvgpu_free(&vm->vma[gmmu_page_size_small], sema_sea->gpu_va);
+                nvgpu_free(&vm->kernel, sema_sea->gpu_va);
                 gk20a_vm_put(vm);
                 return -ENOMEM;
         }
@@ -4273,14 +4267,78 @@ static int gk20a_init_sema_pool(struct vm_gk20a *vm)
         err = gk20a_semaphore_pool_map(vm->sema_pool, vm);
         if (err) {
                 gk20a_semaphore_pool_unmap(vm->sema_pool, vm);
-                nvgpu_free(&vm->vma[gmmu_page_size_small],
-                            vm->sema_pool->gpu_va);
+                nvgpu_free(vm->vma[gmmu_page_size_small],
+                           vm->sema_pool->gpu_va);
                 gk20a_vm_put(vm);
         }
 
         return 0;
 }
 
+/*
+ * Determine if the passed address space can support big pages or not.
+ */
+int gk20a_big_pages_possible(struct vm_gk20a *vm, u64 base, u64 size)
+{
+        u64 mask = ((u64)vm->big_page_size << 10) - 1;
+
+        if (base & mask || size & mask)
+                return 0;
+        return 1;
+}
+
+/*
+ * Attempt to find a reserved memory area to determine PTE size for the passed
+ * mapping. If no reserved area can be found use small pages but drop a warning.
+ */
+enum gmmu_pgsz_gk20a __get_pte_size_fixed_map(struct vm_gk20a *vm,
+                                              u64 base, u64 size)
+{
+        struct vm_reserved_va_node *node;
+
+        node = addr_to_reservation(vm, base);
+        if (!node)
+                return gmmu_page_size_small;
+
+        return node->pgsz_idx;
+}
+
+/**
+ * gk20a_init_vm() - Initialize an address space.
+ *
+ * @mm - Parent MM.
+ * @vm - The VM to init.
+ * @big_page_size - Size of big pages associated with this VM.
+ * @low_hole - The size of the low hole (unaddressable memory at the bottom of
+ *             the address space.
+ * @kernel_reserved - Space reserved for kernel only allocations.
+ * @aperture_size - Total size of the aperture.
+ * @big_pages - Ignored. Will be set based on other passed params.
+ * @name - Name of the address space.
+ *
+ * This function initializes an address space according to the following map:
+ *
+ *     +--+ 0x0
+ *     |  |
+ *     +--+ @low_hole
+ *     |  |
+ *     ~  ~   This is the "user" section.
+ *     |  |
+ *     +--+ @aperture_size - @kernel_reserved
+ *     |  |
+ *     ~  ~   This is the "kernel" section.
+ *     |  |
+ *     +--+ @aperture_size
+ *
+ * The user section is therefor what ever is left over after the @low_hole and
+ * @kernel_reserved memory have been portioned out. The @kernel_reserved is
+ * always persent at the top of the memory space and the @low_hole is always at
+ * the bottom.
+ *
+ * For certain address spaces a "user" section makes no sense (bar1, etc) so in
+ * such cases the @kernel_reserved and @low_hole should sum to exactly
+ * @aperture_size.
+ */
 int gk20a_init_vm(struct mm_gk20a *mm,
                 struct vm_gk20a *vm,
                 u32 big_page_size,
@@ -4293,20 +4351,23 @@ int gk20a_init_vm(struct mm_gk20a *mm,
 {
         int err, i;
         char alloc_name[32];
-        u64 small_vma_start, small_vma_limit, large_vma_start, large_vma_limit,
-                kernel_vma_start, kernel_vma_limit;
+        u64 user_vma_start, user_vma_limit, kernel_vma_start, kernel_vma_limit;
         u32 pde_lo, pde_hi;
         struct gk20a *g = mm->g;
 
         /* note: this must match gmmu_pgsz_gk20a enum */
         u32 gmmu_page_sizes[gmmu_nr_page_sizes] = { SZ_4K, big_page_size, SZ_4K };
 
-        WARN_ON(kernel_reserved + low_hole > aperture_size);
-        if (kernel_reserved > aperture_size)
+        if (WARN_ON(kernel_reserved + low_hole > aperture_size))
                 return -ENOMEM;
 
         vm->mm = mm;
 
+        /* Set up vma pointers. */
+        vm->vma[0] = &vm->user;
+        vm->vma[1] = &vm->user;
+        vm->vma[2] = &vm->kernel;
+
         vm->va_start = low_hole;
         vm->va_limit = aperture_size;
         vm->big_pages = big_pages;
@@ -4321,10 +4382,8 @@ int gk20a_init_vm(struct mm_gk20a *mm,
 
         gk20a_dbg_info("small page-size (%dKB)",
                         vm->gmmu_page_sizes[gmmu_page_size_small] >> 10);
-
-        gk20a_dbg_info("big page-size (%dKB)",
-                        vm->gmmu_page_sizes[gmmu_page_size_big] >> 10);
-
+        gk20a_dbg_info("big page-size (%dKB) (%s)\n",
+                        vm->gmmu_page_sizes[gmmu_page_size_big] >> 10, name);
         gk20a_dbg_info("kernel page-size (%dKB)",
                         vm->gmmu_page_sizes[gmmu_page_size_kernel] >> 10);
 
@@ -4348,38 +4407,27 @@ int gk20a_init_vm(struct mm_gk20a *mm,
                 goto clean_up_pdes;
 
         /* setup vma limits */
-        small_vma_start = low_hole;
-
-        if (big_pages) {
-                /* First 16GB of the address space goes towards small
-                 * pages. What ever remains is allocated to large
-                 * pages. */
-                small_vma_limit = __nv_gmmu_va_small_page_limit();
-                large_vma_start = small_vma_limit;
-                large_vma_limit = vm->va_limit - kernel_reserved;
-        } else {
-                small_vma_limit = vm->va_limit - kernel_reserved;
-                large_vma_start = 0;
-                large_vma_limit = 0;
-        }
+        user_vma_start = low_hole;
+        user_vma_limit = vm->va_limit - kernel_reserved;
 
         kernel_vma_start = vm->va_limit - kernel_reserved;
         kernel_vma_limit = vm->va_limit;
 
         gk20a_dbg_info(
-                "small_vma=[0x%llx,0x%llx) large_vma=[0x%llx,0x%llx) kernel_vma=[0x%llx,0x%llx)\n",
-                small_vma_start, small_vma_limit,
-                large_vma_start, large_vma_limit,
+                "user_vma=[0x%llx,0x%llx) kernel_vma=[0x%llx,0x%llx)\n",
+                user_vma_start, user_vma_limit,
                 kernel_vma_start, kernel_vma_limit);
 
-        /* check that starts do not exceed limits */
-        WARN_ON(small_vma_start > small_vma_limit);
-        WARN_ON(large_vma_start > large_vma_limit);
-        /* kernel_vma must also be non-zero */
+        WARN_ON(user_vma_start > user_vma_limit);
         WARN_ON(kernel_vma_start >= kernel_vma_limit);
 
-        if (small_vma_start > small_vma_limit ||
-            large_vma_start > large_vma_limit ||
+        /*
+         * A "user" area only makes sense for the GVA spaces. For VMs where
+         * there is no "user" area user_vma_start will be equal to
+         * user_vma_limit (i.e a 0 sized space). In such a situation the kernel
+         * area must be non-zero in length.
+         */
+        if (user_vma_start > user_vma_limit ||
             kernel_vma_start >= kernel_vma_limit) {
                 err = -EINVAL;
                 goto clean_up_pdes;
@@ -4389,8 +4437,8 @@ int gk20a_init_vm(struct mm_gk20a *mm,
          * Attempt to make a separate VM for fixed allocations.
          */
         if (g->separate_fixed_allocs &&
-            small_vma_start < small_vma_limit) {
-                if (g->separate_fixed_allocs >= small_vma_limit)
+            user_vma_start < user_vma_limit) {
+                if (g->separate_fixed_allocs >= user_vma_limit)
                         goto clean_up_pdes;
 
                 snprintf(alloc_name, sizeof(alloc_name),
@@ -4398,7 +4446,7 @@ int gk20a_init_vm(struct mm_gk20a *mm,
 
                 err = __nvgpu_buddy_allocator_init(g, &vm->fixed,
                                                    vm, alloc_name,
-                                                   small_vma_start,
+                                                   user_vma_start,
                                                    g->separate_fixed_allocs,
                                                    SZ_4K,
                                                    GPU_BALLOC_MAX_ORDER,
@@ -4407,47 +4455,41 @@ int gk20a_init_vm(struct mm_gk20a *mm,
                         goto clean_up_ptes;
 
                 /* Make sure to update the user vma size. */
-                small_vma_start = g->separate_fixed_allocs;
-        }
-
-        if (small_vma_start < small_vma_limit) {
-                snprintf(alloc_name, sizeof(alloc_name), "gk20a_%s-%dKB", name,
-                         vm->gmmu_page_sizes[gmmu_page_size_small] >> 10);
-                err = __nvgpu_buddy_allocator_init(
-                        g,
-                        &vm->vma[gmmu_page_size_small],
-                        vm, alloc_name,
-                        small_vma_start,
-                        small_vma_limit - small_vma_start,
-                        SZ_4K,
-                        GPU_BALLOC_MAX_ORDER,
-                        GPU_ALLOC_GVA_SPACE);
-                if (err)
-                        goto clean_up_ptes;
+                user_vma_start = g->separate_fixed_allocs;
         }
 
-        if (large_vma_start < large_vma_limit) {
-                snprintf(alloc_name, sizeof(alloc_name), "gk20a_%s-%dKB",
-                         name, vm->gmmu_page_sizes[gmmu_page_size_big] >> 10);
-                err = __nvgpu_buddy_allocator_init(
-                        g,
-                        &vm->vma[gmmu_page_size_big],
-                        vm, alloc_name,
-                        large_vma_start,
-                        large_vma_limit - large_vma_start,
-                        big_page_size,
-                        GPU_BALLOC_MAX_ORDER,
-                        GPU_ALLOC_GVA_SPACE);
+        if (user_vma_start < user_vma_limit) {
+                snprintf(alloc_name, sizeof(alloc_name), "gk20a_%s", name);
+                if (!gk20a_big_pages_possible(vm, user_vma_start,
+                                             user_vma_limit - user_vma_start))
+                        vm->big_pages = false;
+
+                err = __nvgpu_buddy_allocator_init(g, &vm->user,
+                                                   vm, alloc_name,
+                                                   user_vma_start,
+                                                   user_vma_limit -
+                                                   user_vma_start,
+                                                   SZ_4K,
+                                                   GPU_BALLOC_MAX_ORDER,
+                                                   GPU_ALLOC_GVA_SPACE);
                 if (err)
-                        goto clean_up_small_allocator;
+                        goto clean_up_ptes;
+        } else {
+                /*
+                 * Make these allocator pointers point to the kernel allocator
+                 * since we still use the legacy notion of page size to choose
+                 * the allocator.
+                 */
+                vm->vma[0] = &vm->kernel;
+                vm->vma[1] = &vm->kernel;
         }
 
-        snprintf(alloc_name, sizeof(alloc_name), "gk20a_%s-%dKB-sys",
-                 name, vm->gmmu_page_sizes[gmmu_page_size_kernel] >> 10);
-        /*
-         * kernel reserved VMA is at the end of the aperture
-         */
-        err = __nvgpu_buddy_allocator_init(g, &vm->vma[gmmu_page_size_kernel],
+        snprintf(alloc_name, sizeof(alloc_name), "gk20a_%s-sys", name);
+        if (!gk20a_big_pages_possible(vm, kernel_vma_start,
+                                     kernel_vma_limit - kernel_vma_start))
+                vm->big_pages = false;
+
+        err = __nvgpu_buddy_allocator_init(g, &vm->kernel,
                                            vm, alloc_name,
                                            kernel_vma_start,
                                            kernel_vma_limit - kernel_vma_start,
@@ -4455,7 +4497,7 @@ int gk20a_init_vm(struct mm_gk20a *mm,
                                            GPU_BALLOC_MAX_ORDER,
                                            GPU_ALLOC_GVA_SPACE);
         if (err)
-                goto clean_up_big_allocator;
+                goto clean_up_user_allocator;
 
         vm->mapped_buffers = RB_ROOT;
 
@@ -4471,17 +4513,14 @@ int gk20a_init_vm(struct mm_gk20a *mm,
         if (vm->va_limit > SZ_4G) {
                 err = gk20a_init_sema_pool(vm);
                 if (err)
-                        goto clean_up_big_allocator;
+                        goto clean_up_user_allocator;
         }
 
         return 0;
 
-clean_up_big_allocator:
-        if (large_vma_start < large_vma_limit)
-                nvgpu_alloc_destroy(&vm->vma[gmmu_page_size_big]);
-clean_up_small_allocator:
-        if (small_vma_start < small_vma_limit)
-                nvgpu_alloc_destroy(&vm->vma[gmmu_page_size_small]);
+clean_up_user_allocator:
+        if (user_vma_start < user_vma_limit)
+                nvgpu_alloc_destroy(&vm->user);
 clean_up_ptes:
         free_gmmu_pages(vm, &vm->pdb);
 clean_up_pdes:
@@ -4523,9 +4562,10 @@ int gk20a_vm_alloc_share(struct gk20a_as_share *as_share, u32 big_page_size,
         vm->as_share = as_share;
         vm->enable_ctag = true;
 
-        snprintf(name, sizeof(name), "gk20a_as_%d", as_share->id);
+        snprintf(name, sizeof(name), "as_%d", as_share->id);
 
-        err = gk20a_init_vm(mm, vm, big_page_size, big_page_size << 10,
+        err = gk20a_init_vm(mm, vm, big_page_size,
+                            big_page_size << 10,
                             mm->channel.kernel_size,
                             mm->channel.user_size + mm->channel.kernel_size,
                             !mm->disable_bigpage, userspace_managed, name);
@@ -4586,13 +4626,14 @@ int gk20a_vm_alloc_space(struct gk20a_as_share *as_share,
                 goto clean_up;
         }
 
-        vma = &vm->vma[pgsz_idx];
+        vma = vm->vma[pgsz_idx];
         if (args->flags & NVGPU_AS_ALLOC_SPACE_FLAGS_FIXED_OFFSET) {
                 if (nvgpu_alloc_initialized(&vm->fixed))
                         vma = &vm->fixed;
                 vaddr_start = nvgpu_alloc_fixed(vma, args->o_a.offset,
                                                 (u64)args->pages *
-                                                (u64)args->page_size);
+                                                (u64)args->page_size,
+                                                args->page_size);
         } else {
                 vaddr_start = nvgpu_alloc(vma,
                                           (u64)args->pages *
@@ -4662,13 +4703,13 @@ int gk20a_vm_free_space(struct gk20a_as_share *as_share,
                         args->pages, args->offset);
 
         /* determine pagesz idx */
-        pgsz_idx = __nv_gmmu_va_is_big_page_region(vm, args->offset) ?
-                        gmmu_page_size_big : gmmu_page_size_small;
+        pgsz_idx = __get_pte_size(vm, args->offset,
+                                  args->page_size * args->pages);
 
         if (nvgpu_alloc_initialized(&vm->fixed))
                 vma = &vm->fixed;
         else
-                vma = &vm->vma[pgsz_idx];
+                vma = vm->vma[pgsz_idx];
         nvgpu_free(vma, args->offset);
 
         mutex_lock(&vm->update_gmmu_lock);
@@ -4853,11 +4894,10 @@ int gk20a_vm_unmap_buffer(struct vm_gk20a *vm, u64 offset,
 
 void gk20a_deinit_vm(struct vm_gk20a *vm)
 {
-        nvgpu_alloc_destroy(&vm->vma[gmmu_page_size_kernel]);
-        if (nvgpu_alloc_initialized(&vm->vma[gmmu_page_size_big]))
-                nvgpu_alloc_destroy(&vm->vma[gmmu_page_size_big]);
-        if (nvgpu_alloc_initialized(&vm->vma[gmmu_page_size_small]))
-                nvgpu_alloc_destroy(&vm->vma[gmmu_page_size_small]);
+        if (nvgpu_alloc_initialized(&vm->kernel))
+                nvgpu_alloc_destroy(&vm->kernel);
+        if (nvgpu_alloc_initialized(&vm->user))
+                nvgpu_alloc_destroy(&vm->user);
         if (nvgpu_alloc_initialized(&vm->fixed))
                 nvgpu_alloc_destroy(&vm->fixed);
 
@@ -4908,9 +4948,13 @@ static int gk20a_init_bar1_vm(struct mm_gk20a *mm)
 
         mm->bar1.aperture_size = bar1_aperture_size_mb_gk20a() << 20;
         gk20a_dbg_info("bar1 vm size = 0x%x", mm->bar1.aperture_size);
-        gk20a_init_vm(mm, vm, big_page_size, SZ_4K,
-                      mm->bar1.aperture_size - SZ_4K,
-                      mm->bar1.aperture_size, false, false, "bar1");
+        gk20a_init_vm(mm, vm,
+                      big_page_size,
+                      SZ_4K,                            /* Low hole */
+                      mm->bar1.aperture_size - SZ_4K,   /* Kernel reserved. */
+                      mm->bar1.aperture_size,
+                      true, false,
+                      "bar1");
 
         err = gk20a_alloc_inst_block(g, inst_block);
         if (err)
@@ -4932,13 +4976,23 @@ static int gk20a_init_system_vm(struct mm_gk20a *mm)
         struct gk20a *g = gk20a_from_mm(mm);
         struct mem_desc *inst_block = &mm->pmu.inst_block;
         u32 big_page_size = gk20a_get_platform(g->dev)->default_big_page_size;
+        u32 low_hole, aperture_size;
+
+        /*
+         * No user region - so we will pass that as zero sized.
+         */
+        low_hole = SZ_4K * 16;
+        aperture_size = GK20A_PMU_VA_SIZE * 2;
 
         mm->pmu.aperture_size = GK20A_PMU_VA_SIZE;
         gk20a_dbg_info("pmu vm size = 0x%x", mm->pmu.aperture_size);
 
         gk20a_init_vm(mm, vm, big_page_size,
-                      SZ_4K * 16, GK20A_PMU_VA_SIZE,
-                      GK20A_PMU_VA_SIZE * 2, false, false,
+                      low_hole,
+                      aperture_size - low_hole,
+                      aperture_size,
+                      true,
+                      false,
                       "system");
 
         err = gk20a_alloc_inst_block(g, inst_block);