From f5c858cceacb01d4340c6a1e696775d955297d01 Mon Sep 17 00:00:00 2001
From: Tony Kuker <34318535+akuker@users.noreply.github.com>
Date: Mon, 24 Apr 2023 21:18:31 -0500
Subject: [PATCH] Created Run PiSCSI Under Qemu (markdown)

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 Run-PiSCSI-Under-Qemu.md | 70 ++++++++++++++++++++++++++++++++++++++++
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+# Background
+
+You can run the pre-built PiSCSI disk images under Qemu on other hosts. This process is only loosely documented and intended to be used by developers or "power users".
+
+These commands have been used on a M1 Macbook Pro, but should also work the same on an Intel Linux host. The performance on x86_64 is going to be substantially slower than using another ARM platform.
+
+Note: The instructions have only been tested for 64-bit images. The 32-bit instructions may not work and may need updates.
+
+# Download the PiSCSI disk image. 
+
+Take note whether it is the 32 or 64 bit variant. These can be pulled from the [Releases Page](https://github.com/PiSCSI/piscsi/releases)
+
+- Unzip the image and resize it to a multiple of 2GB. 4GB should be plenty.
+```
+unzip image_20xx-xx-xx-PiSCSI-vxx.xx.xx-arm64-lite.zip
+qemu-img resize 20xx-xx-xx-PiSCSI-vxx.xx.xx-arm64-lite.img 4G
+```
+
+- Download custom Kernel and Device Tree for Qemu
+  - [Raspberry Pi 3 Device Tree](https://github.com/farabimahmud/emulate-raspberry-pi3-in-qemu/blob/main/bcm2710-rpi-3-b-plus.dtb)
+  - [64 bit Linux Kernel 8](https://github.com/farabimahmud/emulate-raspberry-pi3-in-qemu/blob/main/kernel8.img) (If you're using a 64 bit image)
+  - [32 bit Linux Kernel 7](https://github.com/dhruvvyas90/qemu-rpi-kernel/blob/master/kernel-qemu-5.10.63-bullseye) (If you're using a 32 bit "Hard Float" image)
+
+# Create launch script
+
+Create a script named `launch.sh` (or whatever you want) in the same directory as the above files. Use the appropriate 32-bit or 64-bit command.
+
+## 32-bit Qemu Launcher
+
+```
+TBD...
+```
+
+## 64-bit Qemu Launcher
+
+```
+#!/bin/bash
+
+qemu-system-aarch64 \
+    -M raspi3b \
+    -cpu cortex-a72 \
+    -append "rw earlyprintk loglevel=8 console=ttyAMA0,115200 dwc_otg.lpm_enable=0 root=/dev/mmcblk0p2 rootdelay=1" \
+    -dtb bcm2710-rpi-3-b-plus.dtb \
+    -sd 2023-04-25-PiSCSI-v23.04.01-arm64-lite.img \
+    -kernel kernel8.img \
+    -m 1G -smp 4 \
+    -serial stdio \
+    -usb -device usb-mouse -device usb-kbd \
+	-device usb-net,netdev=net0 \
+	-netdev user,id=net0,hostfwd=tcp::5555-:22 \
+```
+
+# Make the script executable and launch it
+```
+chmod +x launch.sh
+./launch.sh
+```
+
+# What do the kernel names mean?
+
+* kernel.img is 32-bit for BCM2835 (RPi1 & Zero)
+* kernel7.img is 32-bit for BCM2836 (RPi2) and BCM2837 (RPi3)
+* kernel7l.img is 32-bit for BCM2711 (RPi4)
+* kernel8.img is 64-bit for BCM2837 (RPi3) or BCM2711 (RPi4)
+
+
+# References
+
+* https://github.com/dhruvvyas90/qemu-rpi-kernel/wiki
+* https://github.com/farabimahmud/emulate-raspberry-pi3-in-qemu