ggml-virtgpu: improve the reliability of the code (#19846)

* ggml-virtgpu-backend: validate the consistency of the received objects

This patch adds consistency checks in the
ggml-virtgpu-backend (running on the host side) to ensure that the
data received from the guest is consistent (valid pointers, valid
sizes and offsets).

* ggml-virtgpu-backend: add fallback/skips for optional ggml backend methods

```
  1. bck->iface.synchronize(bck)
  2. buft->iface.get_alloc_size(buft, op)
  3. buft->iface.get_max_size(buft)
```

these three methods are optional in the GGML interface. `get_max_size`
was already properly defaulted, but `backend sychronize` and `butf
get_max_size` would have segfaulted the backend if not implemented.

* ggml-virtgpu-backend: fix log format missing argument

* ggml-virtgpu-backend: improve the abort message

* ggml-virtgpu-backend: more safety checks

* ggml-virtgpu-backend: new error code

* ggml-virtgpu-backend: initialize all the error codes

* ggml-virtgpu: add a missing comment generated by the code generator

* ggml-virtgpu: add the '[virtgpu]' prefix to the device/buffer names

* ggml-virtgpu: apir_device_buffer_from_ptr: improve the error message

* ggml-virtgpu: shared: make it match the latest api_remoting.h of Virglrenderer APIR

(still unmerged)

* ggml-virtgpu: update the code generator to have dispatch_command_name in a host/guest shared file

* ggml-virtgpu: REMOTE_CALL: fail if the backend returns an error

* docs/backend/VirtGPU.md: indicate that the RAM+VRAM size is limed to 64 GB with libkrun

* ggml-virtgpu: turn off clang-format header ordering for some of the files

Compilation breaks when ordered alphabetically.

* ggml-virtgpu: clang-format

* ggml-virtgpu/backend/shared/api_remoting: better comments for the APIR return codes

ggml/src/ggml-virtgpu/ggml-backend-device.cpp

@@ -3,6 +3,7 @@
 static const char * ggml_backend_remoting_device_get_name(ggml_backend_dev_t dev) {
     virtgpu * gpu = DEV_TO_GPU(dev);
 
+    // Return the prefixed name that was built once during initialization
     return gpu->cached_device_info.name;
 }
 
@@ -22,7 +23,7 @@ static enum ggml_backend_dev_type ggml_backend_remoting_device_get_type(ggml_bac
 static void ggml_backend_remoting_device_get_memory(ggml_backend_dev_t dev, size_t * free, size_t * total) {
     virtgpu * gpu = DEV_TO_GPU(dev);
 
-    *free = gpu->cached_device_info.memory_free;
+    *free  = gpu->cached_device_info.memory_free;
     *total = gpu->cached_device_info.memory_total;
 }
 
@@ -72,7 +73,7 @@ static void ggml_backend_remoting_device_get_props(ggml_backend_dev_t dev, ggml_
 ggml_backend_buffer_type_t ggml_backend_remoting_device_get_buffer_type(ggml_backend_dev_t dev) {
     virtgpu * gpu = DEV_TO_GPU(dev);
 
-    static std::atomic<bool> initialized = false;
+    static std::atomic<bool>        initialized = false;
     static ggml_backend_buffer_type buft;
 
     if (!initialized) {
@@ -95,7 +96,7 @@ ggml_backend_buffer_type_t ggml_backend_remoting_device_get_buffer_type(ggml_bac
 static ggml_backend_buffer_type_t ggml_backend_remoting_device_get_buffer_from_ptr_type(ggml_backend_dev_t dev) {
     virtgpu * gpu = DEV_TO_GPU(dev);
 
-    static std::atomic<bool> initialized = false;
+    static std::atomic<bool>        initialized = false;
     static ggml_backend_buffer_type buft;
 
     if (!initialized) {