anv/allocator: Add a BO cache

This cache allows us to easily ensure that we have a unique anv_bo for
each gem handle.  We'll need this in order to support multiple-import of
memory objects and semaphores.

v2 (Jason Ekstrand):
 - Reject BO imports if the size doesn't match the prime fd size as
   reported by lseek().

Reviewed-by: Chad Versace <[email protected]>

2 files changed, 278 insertions, 0 deletions

diff --git a/src/intel/vulkan/anv_allocator.c b/src/intel/vulkan/anv_allocator.c
index 7e4db1aeb65..554ca4ac5fa 100644
--- a/src/intel/vulkan/anv_allocator.c
+++ b/src/intel/vulkan/anv_allocator.c
@@ -34,6 +34,8 @@
 
 #include "anv_private.h"
 
+#include "util/hash_table.h"
+
 #ifdef HAVE_VALGRIND
 #define VG_NOACCESS_READ(__ptr) ({                       \
    VALGRIND_MAKE_MEM_DEFINED((__ptr), sizeof(*(__ptr))); \
@@ -1023,3 +1025,258 @@ anv_scratch_pool_alloc(struct anv_device *device, struct anv_scratch_pool *pool,
 
    return &bo->bo;
 }
+
+struct anv_cached_bo {
+   struct anv_bo bo;
+
+   uint32_t refcount;
+};
+
+VkResult
+anv_bo_cache_init(struct anv_bo_cache *cache)
+{
+   cache->bo_map = _mesa_hash_table_create(NULL, _mesa_hash_pointer,
+                                           _mesa_key_pointer_equal);
+   if (!cache->bo_map)
+      return vk_error(VK_ERROR_OUT_OF_HOST_MEMORY);
+
+   if (pthread_mutex_init(&cache->mutex, NULL)) {
+      _mesa_hash_table_destroy(cache->bo_map, NULL);
+      return vk_errorf(VK_ERROR_OUT_OF_HOST_MEMORY,
+                       "pthread_mutex_init failed: %m");
+   }
+
+   return VK_SUCCESS;
+}
+
+void
+anv_bo_cache_finish(struct anv_bo_cache *cache)
+{
+   _mesa_hash_table_destroy(cache->bo_map, NULL);
+   pthread_mutex_destroy(&cache->mutex);
+}
+
+static struct anv_cached_bo *
+anv_bo_cache_lookup_locked(struct anv_bo_cache *cache, uint32_t gem_handle)
+{
+   struct hash_entry *entry =
+      _mesa_hash_table_search(cache->bo_map,
+                              (const void *)(uintptr_t)gem_handle);
+   if (!entry)
+      return NULL;
+
+   struct anv_cached_bo *bo = (struct anv_cached_bo *)entry->data;
+   assert(bo->bo.gem_handle == gem_handle);
+
+   return bo;
+}
+
+static struct anv_bo *
+anv_bo_cache_lookup(struct anv_bo_cache *cache, uint32_t gem_handle)
+{
+   pthread_mutex_lock(&cache->mutex);
+
+   struct anv_cached_bo *bo = anv_bo_cache_lookup_locked(cache, gem_handle);
+
+   pthread_mutex_unlock(&cache->mutex);
+
+   return bo ? &bo->bo : NULL;
+}
+
+VkResult
+anv_bo_cache_alloc(struct anv_device *device,
+                   struct anv_bo_cache *cache,
+                   uint64_t size, struct anv_bo **bo_out)
+{
+   struct anv_cached_bo *bo =
+      vk_alloc(&device->alloc, sizeof(struct anv_cached_bo), 8,
+               VK_SYSTEM_ALLOCATION_SCOPE_OBJECT);
+   if (!bo)
+      return vk_error(VK_ERROR_OUT_OF_HOST_MEMORY);
+
+   bo->refcount = 1;
+
+   /* The kernel is going to give us whole pages anyway */
+   size = align_u64(size, 4096);
+
+   VkResult result = anv_bo_init_new(&bo->bo, device, size);
+   if (result != VK_SUCCESS) {
+      vk_free(&device->alloc, bo);
+      return result;
+   }
+
+   assert(bo->bo.gem_handle);
+
+   pthread_mutex_lock(&cache->mutex);
+
+   _mesa_hash_table_insert(cache->bo_map,
+                           (void *)(uintptr_t)bo->bo.gem_handle, bo);
+
+   pthread_mutex_unlock(&cache->mutex);
+
+   *bo_out = &bo->bo;
+
+   return VK_SUCCESS;
+}
+
+VkResult
+anv_bo_cache_import(struct anv_device *device,
+                    struct anv_bo_cache *cache,
+                    int fd, uint64_t size, struct anv_bo **bo_out)
+{
+   pthread_mutex_lock(&cache->mutex);
+
+   /* The kernel is going to give us whole pages anyway */
+   size = align_u64(size, 4096);
+
+   uint32_t gem_handle = anv_gem_fd_to_handle(device, fd);
+   if (!gem_handle) {
+      pthread_mutex_unlock(&cache->mutex);
+      return vk_error(VK_ERROR_INVALID_EXTERNAL_HANDLE_KHX);
+   }
+
+   struct anv_cached_bo *bo = anv_bo_cache_lookup_locked(cache, gem_handle);
+   if (bo) {
+      if (bo->bo.size != size) {
+         pthread_mutex_unlock(&cache->mutex);
+         return vk_error(VK_ERROR_INVALID_EXTERNAL_HANDLE_KHX);
+      }
+      __sync_fetch_and_add(&bo->refcount, 1);
+   } else {
+      /* For security purposes, we reject BO imports where the size does not
+       * match exactly.  This prevents a malicious client from passing a
+       * buffer to a trusted client, lying about the size, and telling the
+       * trusted client to try and texture from an image that goes
+       * out-of-bounds.  This sort of thing could lead to GPU hangs or worse
+       * in the trusted client.  The trusted client can protect itself against
+       * this sort of attack but only if it can trust the buffer size.
+       */
+      off_t import_size = lseek(fd, 0, SEEK_END);
+      if (import_size == (off_t)-1 || import_size != size) {
+         anv_gem_close(device, gem_handle);
+         pthread_mutex_unlock(&cache->mutex);
+         return vk_error(VK_ERROR_INVALID_EXTERNAL_HANDLE_KHX);
+      }
+
+      bo = vk_alloc(&device->alloc, sizeof(struct anv_cached_bo), 8,
+                    VK_SYSTEM_ALLOCATION_SCOPE_OBJECT);
+      if (!bo) {
+         anv_gem_close(device, gem_handle);
+         pthread_mutex_unlock(&cache->mutex);
+         return vk_error(VK_ERROR_OUT_OF_HOST_MEMORY);
+      }
+
+      bo->refcount = 1;
+
+      anv_bo_init(&bo->bo, gem_handle, size);
+
+      if (device->instance->physicalDevice.supports_48bit_addresses)
+         bo->bo.flags |= EXEC_OBJECT_SUPPORTS_48B_ADDRESS;
+
+      if (device->instance->physicalDevice.has_exec_async)
+         bo->bo.flags |= EXEC_OBJECT_ASYNC;
+
+      _mesa_hash_table_insert(cache->bo_map, (void *)(uintptr_t)gem_handle, bo);
+   }
+
+   pthread_mutex_unlock(&cache->mutex);
+
+   /* From the Vulkan spec:
+    *
+    *    "Importing memory from a file descriptor transfers ownership of
+    *    the file descriptor from the application to the Vulkan
+    *    implementation. The application must not perform any operations on
+    *    the file descriptor after a successful import."
+    *
+    * If the import fails, we leave the file descriptor open.
+    */
+   close(fd);
+
+   *bo_out = &bo->bo;
+
+   return VK_SUCCESS;
+}
+
+VkResult
+anv_bo_cache_export(struct anv_device *device,
+                    struct anv_bo_cache *cache,
+                    struct anv_bo *bo_in, int *fd_out)
+{
+   assert(anv_bo_cache_lookup(cache, bo_in->gem_handle) == bo_in);
+   struct anv_cached_bo *bo = (struct anv_cached_bo *)bo_in;
+
+   int fd = anv_gem_handle_to_fd(device, bo->bo.gem_handle);
+   if (fd < 0)
+      return vk_error(VK_ERROR_TOO_MANY_OBJECTS);
+
+   *fd_out = fd;
+
+   return VK_SUCCESS;
+}
+
+static bool
+atomic_dec_not_one(uint32_t *counter)
+{
+   uint32_t old, val;
+
+   val = *counter;
+   while (1) {
+      if (val == 1)
+         return false;
+
+      old = __sync_val_compare_and_swap(counter, val, val - 1);
+      if (old == val)
+         return true;
+
+      val = old;
+   }
+}
+
+void
+anv_bo_cache_release(struct anv_device *device,
+                     struct anv_bo_cache *cache,
+                     struct anv_bo *bo_in)
+{
+   assert(anv_bo_cache_lookup(cache, bo_in->gem_handle) == bo_in);
+   struct anv_cached_bo *bo = (struct anv_cached_bo *)bo_in;
+
+   /* Try to decrement the counter but don't go below one.  If this succeeds
+    * then the refcount has been decremented and we are not the last
+    * reference.
+    */
+   if (atomic_dec_not_one(&bo->refcount))
+      return;
+
+   pthread_mutex_lock(&cache->mutex);
+
+   /* We are probably the last reference since our attempt to decrement above
+    * failed.  However, we can't actually know until we are inside the mutex.
+    * Otherwise, someone could import the BO between the decrement and our
+    * taking the mutex.
+    */
+   if (unlikely(__sync_sub_and_fetch(&bo->refcount, 1) > 0)) {
+      /* Turns out we're not the last reference.  Unlock and bail. */
+      pthread_mutex_unlock(&cache->mutex);
+      return;
+   }
+
+   struct hash_entry *entry =
+      _mesa_hash_table_search(cache->bo_map,
+                              (const void *)(uintptr_t)bo->bo.gem_handle);
+   assert(entry);
+   _mesa_hash_table_remove(cache->bo_map, entry);
+
+   if (bo->bo.map)
+      anv_gem_munmap(bo->bo.map, bo->bo.size);
+
+   anv_gem_close(device, bo->bo.gem_handle);
+
+   /* Don't unlock until we've actually closed the BO.  The whole point of
+    * the BO cache is to ensure that we correctly handle races with creating
+    * and releasing GEM handles and we don't want to let someone import the BO
+    * again between mutex unlock and closing the GEM handle.
+    */
+   pthread_mutex_unlock(&cache->mutex);
+
+   vk_free(&device->alloc, bo);
+}
diff --git a/src/intel/vulkan/anv_private.h b/src/intel/vulkan/anv_private.h
index 36a67606153..7ebcfefeb12 100644
--- a/src/intel/vulkan/anv_private.h
+++ b/src/intel/vulkan/anv_private.h
@@ -604,6 +604,27 @@ struct anv_bo *anv_scratch_pool_alloc(struct anv_device *device,
                                       gl_shader_stage stage,
                                       unsigned per_thread_scratch);
 
+/** Implements a BO cache that ensures a 1-1 mapping of GEM BOs to anv_bos */
+struct anv_bo_cache {
+   struct hash_table *bo_map;
+   pthread_mutex_t mutex;
+};
+
+VkResult anv_bo_cache_init(struct anv_bo_cache *cache);
+void anv_bo_cache_finish(struct anv_bo_cache *cache);
+VkResult anv_bo_cache_alloc(struct anv_device *device,
+                            struct anv_bo_cache *cache,
+                            uint64_t size, struct anv_bo **bo);
+VkResult anv_bo_cache_import(struct anv_device *device,
+                             struct anv_bo_cache *cache,
+                             int fd, uint64_t size, struct anv_bo **bo);
+VkResult anv_bo_cache_export(struct anv_device *device,
+                             struct anv_bo_cache *cache,
+                             struct anv_bo *bo_in, int *fd_out);
+void anv_bo_cache_release(struct anv_device *device,
+                          struct anv_bo_cache *cache,
+                          struct anv_bo *bo);
+
 struct anv_physical_device {
     VK_LOADER_DATA                              _loader_data;