Add iommu definitions.

README.md

@@ -173,19 +173,24 @@ Then, there are certain settings and commands we recommend doing:
 
 2. Possibly, you have to disable and reenable your Wired/WLAN connection to get internet connection.
 
-3. Install Firefox:
+3. Hold packages to prevent updating the kernel when doing `apt upgrade`:
+   ```bash
+   sudo apt-mark hold linux-generic linux-generic-hwe-24.04 linux-generic-hwe-26.04 linux-image-generic linux-image-generic-hwe-24.04 linux-image-generic-hwe-26.04 linux-headers-generic linux-headers-generic-hwe-24.04 linux-headers-generic-hwe-26.04
+   ```
+
+4. Install Firefox:
 
    ```bash
    sudo snap install firefox
    ```
 
-4. Update mesa:
+5. Update mesa:
 
    ```bash
    sudo snap refresh mesa-2404 --channel=latest/edge
    ```
 
-5. Clone our [ps5-linux-tools](https://github.com/ps5-linux/ps5-linux-tools):
+6. Clone our [ps5-linux-tools](https://github.com/ps5-linux/ps5-linux-tools):
 
    ```bash
    sudo apt install zlib1g-dev
@@ -198,17 +203,18 @@ Then, there are certain settings and commands we recommend doing:
 
 You can use a M.2 SSD exclusively for Linux (which means you cannot use it for PS5 game storage).
 
-1. Attach the M.SSD and format it on your PS5.
-2. Boot Linux on your PS5 and run these commands to initialize your M.2:
+1. Attach the M.2 SSD by following the [official guide](https://www.playstation.com/en-us/support/hardware/ps5-install-m2-ssd).
+2. **VERY IMPORTANT**: If you used the M2. SSD for games before, reformat it on the PS5 under `Settings` → `Storage` → `M.2 SSD Storage`.
+3. Boot Linux on your PS5 and run these commands to initialize your M.2:
 
 ```bash
 cd ps5-linux-tools
 sudo ./m2_init
 ```
 
-3. Reboot via `sudo reboot`. If your PS5 asks you to format your M.2 again, please report this issue to us in our [Discord server](https://discord.gg/PeMGVB7BAm) and provide your M.2 model and storage size.
-4. Relaunch Linux on your PS5.
-5. Copy the `ps5-ubuntu2604.img` image that you built during installation or rebuild it on your PS5. Then, install it onto your M.2:
+4. Reboot via `sudo reboot`. If your PS5 asks you to format your M.2 again, please report this issue to us in our [Discord server](https://discord.gg/PeMGVB7BAm) and provide your M.2 model and storage size.
+5. Relaunch Linux on your PS5.
+6. Copy the `ps5-ubuntu2604.img` image that you built during installation or rebuild it on your PS5. Then, install it onto your M.2:
 
 ```bash
 cd ps5-linux-tools
@@ -260,6 +266,7 @@ Always turn on fan when your turn on boost, as this is what the official PS5 OS
 
 ## Tips and tricks
 
+- If you see graphical issues in your games, add the environment variable `RADV_DEBUG=nohiz` as [recommended for BC250](https://elektricm.github.io/amd-bc250-docs/drivers/environment/#critical-environment-variables) as well.
 - You can adjust the kernel cmdline in `cmdline.txt` in the FAT32 partition.
 - You can adjust the VRAM size in `vram.txt` in the FAT32 partition. By default, it uses 512MB (0x20000000) which enables [Dynamic VRAM allocation](https://elektricm.github.io/amd-bc250-docs/bios/flashing/#why-flash-the-bios).
 - Monitor hotswap may work, but it will not change resolution automatically.

shellcode_hypervisor/boot_linux.c

@@ -159,7 +159,7 @@ void entry(void) {
   }
 
   // Disable IOMMU.
-  *(volatile uint64_t *)0xfdd80018 &= ~1;
+  *(volatile uint64_t *)(AMDIOMMU_MMIO_BASE + AMDIOMMU_CTRL) &= ~1;
 
   memcpy(&info, (void *)(cave_linux_info), sizeof(struct linux_info));
 

shellcode_hypervisor/boot_linux.h

@@ -37,7 +37,10 @@
 #define DCHUBBUB_WHITELIST_BASE_ADDR_0 0x24878
 #define DCHUBBUB_WHITELIST_TOP_ADDR_0 0x2487c
 
+#define AMDIOMMU_MMIO_BASE 0xfdd80000
+#define AMDIOMMU_CTRL 0x18
+
 #define MAXCPU 16
 
 void entry(void);
-void boot_linux(void);
+void boot_linux(void);