intel/tools: load json device info in drm_shim

Enable drm_shim to parse a serialized intel_device_info structure from
json.  When overriding the gpu hardware, drm_shim provides the stubbed
intel_device_info structure to mesa through an unused ioctl.

Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27557>

src/intel/common/intel_gem.h

@@ -38,6 +38,7 @@ extern "C" {
 #include <sys/ioctl.h>
 
 #include "intel_engine.h"
+#include "drm-uapi/drm.h"
 #include "util/macros.h"
 
 #define RCS_TIMESTAMP 0x2358
@@ -130,6 +131,15 @@ bool intel_gem_create_context_ext(int fd, enum intel_gem_create_context_flags fl
 bool intel_gem_supports_protected_context(int fd,
                                           enum intel_kmd_type kmd_type);
 
+#define DRM_IOCTL_I915_LAST             DRM_IO(DRM_COMMAND_END - 1)
+
+struct drm_intel_stub_devinfo {
+   uint64_t addr;
+   uint32_t size;
+};
+
+#define DRM_IOCTL_INTEL_STUB_DEVINFO    DRM_IOR(DRM_IOCTL_I915_LAST, struct drm_intel_stub_devinfo)
+
 #ifdef __cplusplus
 }
 #endif

src/intel/dev/intel_device_info.c

@@ -35,6 +35,7 @@
 #include "i915/intel_device_info.h"
 #include "xe/intel_device_info.h"
 
+#include "common/intel_gem.h"
 #include "util/u_debug.h"
 #include "util/log.h"
 #include "util/macros.h"
@@ -1631,6 +1632,21 @@ intel_device_info_calc_engine_prefetch(const struct intel_device_info *devinfo,
 bool
 intel_get_device_info_from_fd(int fd, struct intel_device_info *devinfo, int min_ver, int max_ver)
 {
+   if (NULL != getenv("INTEL_STUB_GPU_JSON")) {
+      /* This call will succeed when shim-drm has been initialized with a
+       * serialized intel_device_info structure.
+       */
+      struct drm_intel_stub_devinfo arg = {
+         .addr = (uintptr_t)devinfo,
+         .size = sizeof(*devinfo),
+      };
+      if (0 == intel_ioctl(fd, DRM_IOCTL_INTEL_STUB_DEVINFO, &arg)) {
+         intel_device_info_init_was(devinfo);
+         intel_device_info_apply_workarounds(devinfo);
+         return true;
+      }
+   }
+
    /* Get PCI info.
     *
     * Some callers may already have a valid drm device which holds values of
@@ -1780,3 +1796,4 @@ intel_device_info_wa_stepping(struct intel_device_info *devinfo)
    /* all other platforms support only released steppings */
    return INTEL_STEPPING_RELEASE;
 }
+

src/intel/tools/intel_noop_drm_shim.c

@@ -34,6 +34,7 @@
 
 #include "common/intel_gem.h"
 #include "dev/intel_device_info.h"
+#include "dev/intel_device_info_serialize.h"
 #include "drm-uapi/i915_drm.h"
 #include "drm-shim/drm_shim.h"
 #include "util/macros.h"
@@ -51,6 +52,7 @@ struct i915_bo {
 };
 
 static struct i915_device i915 = {};
+static bool i915_device_from_json = false;
 
 bool drm_shim_driver_prefers_first_render_node = true;
 
@@ -489,6 +491,31 @@ i915_gem_get_aperture(int fd, unsigned long request, void *arg)
    return 0;
 }
 
+/* Provide a binary blob of struct intel_device_info to the caller
+ *
+ * This is used in conjunction with INTEL_STUB_GPU_JSON to initialize a
+ * stubbed driver with device info from a file.
+ */
+static int
+i915_ioctl_load_device_info(int fd, unsigned long request, void *arg)
+{
+   if(!i915_device_from_json)
+      return -1;
+
+   struct drm_intel_stub_devinfo *stub_arg = (struct drm_intel_stub_devinfo*) arg;
+   struct intel_device_info *stub_info = (struct intel_device_info*) stub_arg->addr;
+
+   if (stub_arg->size != sizeof(i915.devinfo)) {
+      assert(false);
+      return -1;
+   }
+   memcpy(stub_info, &i915.devinfo, sizeof(i915.devinfo));
+   return 0;
+}
+
+#define DRM_I915_LAST (DRM_COMMAND_END - DRM_COMMAND_BASE - 1)
+#define DRM_I915_LOAD_STUB_DEVINFO DRM_I915_LAST
+
 static ioctl_fn_t driver_ioctls[] = {
    [DRM_I915_GETPARAM] = i915_ioctl_get_param,
    [DRM_I915_QUERY] = i915_ioctl_query,
@@ -521,25 +548,33 @@ static ioctl_fn_t driver_ioctls[] = {
    [DRM_I915_GEM_MADVISE] = i915_ioctl_noop,
    [DRM_I915_GEM_WAIT] = i915_ioctl_noop,
    [DRM_I915_GEM_BUSY] = i915_ioctl_noop,
+   [DRM_I915_LOAD_STUB_DEVINFO] = i915_ioctl_load_device_info,
 };
 
 void
 drm_shim_driver_init(void)
 {
    i915.device_id = 0;
-   const char *device_id_str = getenv("INTEL_STUB_GPU_DEVICE_ID");
-   if (device_id_str != NULL) {
-      /* Set as 0 if strtoul fails */
-      i915.device_id = strtoul(device_id_str, NULL, 16);
+   const char *json_dev_str = getenv("INTEL_STUB_GPU_JSON");
+   if (json_dev_str != NULL) {
+      if (!intel_device_info_from_json(json_dev_str, &i915.devinfo))
+         return;
+      i915.device_id = i915.devinfo.pci_device_id;
+      i915_device_from_json = true;
+   } else {
+      const char *device_id_str = getenv("INTEL_STUB_GPU_DEVICE_ID");
+      if (device_id_str != NULL) {
+         /* Set as 0 if strtoul fails */
+         i915.device_id = strtoul(device_id_str, NULL, 16);
+      }
+      if (i915.device_id == 0) {
+         const char *user_platform = getenv("INTEL_STUB_GPU_PLATFORM");
+         /* Use SKL if nothing is specified. */
+         i915.device_id = intel_device_name_to_pci_device_id(user_platform ?: "skl");
+      }
+      if (!intel_get_device_info_from_pci_id(i915.device_id, &i915.devinfo))
+         return;
    }
-   if (i915.device_id == 0) {
-      const char *user_platform = getenv("INTEL_STUB_GPU_PLATFORM");
-      /* Use SKL if nothing is specified. */
-      i915.device_id = intel_device_name_to_pci_device_id(user_platform ?: "skl");
-   }
-
-   if (!intel_get_device_info_from_pci_id(i915.device_id, &i915.devinfo))
-      return;
 
    shim_device.bus_type = DRM_BUS_PCI;
    shim_device.driver_name = "i915";

src/intel/tools/meson.build

@@ -156,9 +156,9 @@ if with_tools.contains('drm-shim')
 
   libintel_stub_gpu = shared_library(
     'intel_noop_drm_shim',
-    'intel_noop_drm_shim.c',
+    ['intel_noop_drm_shim.c', intel_dev_serialize_src],
     include_directories: [inc_include, inc_src, inc_intel],
-    dependencies: [dep_libdrm, dep_drm_shim, idep_mesautil, idep_libintel_common, idep_intel_dev],
+    dependencies: [dep_libdrm, dep_drm_shim, idep_mesautil, idep_libintel_common, idep_intel_dev, idep_parson],
     gnu_symbol_visibility : 'hidden',
     install : true,
   )