From 3997ec4d2d7d6f69b08d0c04ce8de0df03c52a45 Mon Sep 17 00:00:00 2001
From: salmonik <salmonik@tuta.io>
Date: Fri, 31 Jul 2026 21:29:49 +0200
Subject: ahci: scan all ports; fat: mount first valid FAT32 disk

The kernel previously started only AHCI port 0, so any launch where the
firmware/QEMU put something else on port 0 (e.g. the ESP from an implicit
-drive file=fat:rw:esp) left the real disk unnoticed: 'unsupported sector
size 0' and no mount.

- ahci.rs: enumerate CAP.NP/PI ports, start every port that links up
  (empty ports settle at DET=0 and are skipped quickly), keep up to 8
  disks, and expose disk_count()/select() for the filesystem
- fat.rs: try each disk in port order and mount the first valid FAT32
  volume; non-FAT disks are logged and skipped
- scripts/boot.sh: attach the data disk on ide.0 and the ESP on ide.1
  (DISK_IMG env var, default /tmp/disk.img), matching the Makefile
- Verified with the disk on port 0 (Makefile style), port 5 (old-style
  command line), and with the ESP on port 0; fsck.fat stays clean
---
 scripts/boot.sh | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

(limited to 'scripts/boot.sh')

diff --git a/scripts/boot.sh b/scripts/boot.sh
index 1e3f739..26064f9 100755
--- a/scripts/boot.sh
+++ b/scripts/boot.sh
@@ -19,6 +19,11 @@
 #   OVMF    path to OVMF firmware (default: /usr/share/edk2/x64/OVMF.4m.fd)
 #   MEM     memory size (default: 256M)
 #   SMP     CPU count (default: 1)
+#   DISK_IMG raw disk image attached as the SATA data disk (default: /tmp/disk.img)
+#
+# The data disk is pinned to AHCI port 0 (ide.0) and the ESP to port 1
+# (ide.1); the implicit `-drive file=fat:rw:esp` would otherwise grab
+# port 0 and the kernel would find the ESP where it expects a FAT32 disk.
 #
 set -euo pipefail
 
@@ -33,6 +38,7 @@ ESP_DIR="$PROJECT_DIR/esp"
 OVMF="${OVMF:-/usr/share/edk2/x64/OVMF.4m.fd}"
 MEM="${MEM:-256M}"
 SMP="${SMP:-1}"
+DISK_IMG="${DISK_IMG:-/tmp/disk.img}"
 PROFILE="debug"
 CARGO_FLAGS=""
 GUI=""
@@ -84,13 +90,25 @@ echo ""
 echo "=== Booting (direct: firmware → rsnix) ==="
 echo "  ovmf:  $OVMF"
 echo "  mem:   $MEM   smp: $SMP"
+echo "  disk:  $([ -f "$DISK_IMG" ] && echo "$DISK_IMG" || echo "none ($DISK_IMG missing)")"
 echo "  gui:   $([ -n "$GUI" ] && echo yes || echo no)"
 echo "  gdb:   $([ -n "$DEBUG" ] && echo ':1234' || echo off)"
 echo ""
 
+if [ -f "$DISK_IMG" ]; then
+	DISK_ARGS=(
+		-drive "file=$DISK_IMG,format=raw,if=none,id=disk"
+		-device ide-hd,drive=disk,bus=ide.0
+	)
+else
+	DISK_ARGS=()
+fi
+
 exec qemu-system-x86_64 \
 	-bios "$OVMF" \
-	-drive file=fat:rw:"$ESP_DIR",format=raw \
+	"${DISK_ARGS[@]}" \
+	-drive file=fat:rw:"$ESP_DIR",format=raw,if=none,id=esp \
+	-device ide-hd,drive=esp,bus=ide.1 \
 	-serial stdio \
 	-m "$MEM" \
 	-machine q35 \
-- 
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