[nvdrv] Implement SetErrorNotifier

Implements SetErrorNotifier() based on Switch kernel behavior.
Only mem is used; other fields are ignored. Guest misuse of offset or size is logged as an error and rejected.
Games like Super Mario Odyssey or Xenoblade may use this mechanism to detect timeouts.

src/core/hle/service/nvdrv/devices/nvhost_gpu.cpp

@@ -161,8 +161,21 @@ NvResult nvhost_gpu::ZCullBind(IoctlZCullBind& params) {
 }
 
 NvResult nvhost_gpu::SetErrorNotifier(IoctlSetErrorNotifier& params) {
-    LOG_WARNING(Service_NVDRV, "(STUBBED) called, offset={:X}, size={:X}, mem={:X}", params.offset,
-                params.size, params.mem);
+    if (params.mem == 0) {
+        LOG_DEBUG(Service_NVDRV, "called, SetErrorNotifier deinitialized");
+        error_notifier_mem = 0;
+        return NvResult::Success;
+    }
+
+    if (params.offset != 0 || params.size != 0) {
+        LOG_ERROR(Service_NVDRV,
+                  "called, SetErrorNotifier received non-zero offset/size (ignored): offset=0x{:X}, size=0x{:X}",
+                  params.offset, params.size);
+        return NvResult::BadParameter;
+    }
+
+    LOG_DEBUG(Service_NVDRV, "called, SetErrorNotifier initialized, mem=0x{:X}", params.mem);
+    error_notifier_mem = params.mem;
     return NvResult::Success;
 }
 
@@ -228,7 +241,7 @@ NvResult nvhost_gpu::AllocateObjectContext(IoctlAllocObjCtx& params) {
         return NvResult::NotInitialized;
     }
 
-    switch (static_cast<CtxClasses>(params.class_num)) { 
+    switch (static_cast<CtxClasses>(params.class_num)) {
     case CtxClasses::Ctx2D:
     case CtxClasses::Ctx3D:
     case CtxClasses::CtxCompute:

src/core/hle/service/nvdrv/devices/nvhost_gpu.h

@@ -172,6 +172,7 @@ private:
     s32_le nvmap_fd{};
     u64_le user_data{};
     IoctlZCullBind zcull_params{};
+    u32_le error_notifier_mem{};
     std::vector<IoctlAllocObjCtx> ctxObj_params{};
     u32_le channel_priority{};
     u32_le channel_timeslice{};