Add qemu support for Lagarto Ox

The network is still not working automatically, but the eth0 device is
present in the host.

Reviewed-by: Rodrigo Arias Mallo <rodrigo.arias@bsc.es>

README.md

@@ -45,6 +45,20 @@ $ picocom -q -b 115200 $FPGACTL_UART
 
 It should boot without any user interaction.
 
+## Lagarto Ox on QEMU
+
+To build the system and boot it on QEMU, you can run the following:
+
+```
+$ nix develop -L '.#qemu-lagarto-ox'
+```
+
+Then, simply run boot.sh to start the QEMU system.
+
+```
+$ ./boot.sh
+```
+
 ## Lagarto Hun
 
 WIP

boot.sh

@@ -27,7 +27,7 @@ fi
 # Create a directory for exchanging data with the VM.
 mkdir -p "$TMPDIR/xchg"
 
-system="$NIXOS_SYSTEM_TOPLEVEL"
+system="$TOPLEVEL"
 echo "Booting $system"
 
 cd "$TMPDIR"
@@ -37,7 +37,7 @@ cd "$TMPDIR"
 #QEMU_KERNEL_PARAMS="boot.trace boot.debug1"
 
 # Trap the CPU on compressed instructions?
-TRAP_COMPRESSED="-cpu rv64,c=false"
+#TRAP_COMPRESSED="-cpu rv64,c=false"
 
 CUSTOM_BIOS="-bios $OPENSBI/share/opensbi/lp64/generic/firmware/fw_payload.bin"
 #CUSTOM_BIOS="-bios $OPENSBI/share/opensbi/lp64/generic/firmware/fw_jump.elf"
@@ -45,11 +45,10 @@ CUSTOM_BIOS="-bios $OPENSBI/share/opensbi/lp64/generic/firmware/fw_payload.bin"
 #CUSTOM_BIOS="-bios $CDIR/bios.bin"
 #CUSTOM_BIOS="-bios opensbi-1.4-rv-bin/share/opensbi/lp64/generic/firmware/fw_payload.bin"
 #DEBUG_GDB="-s -S"
-DEBUG_CPU="-d cpu_reset"
+#DEBUG_CPU="-d cpu_reset"
 #DEBUG_CPU="-d in_asm,cpu,cpu_reset"
 
 
-# Start QEMU.
 exec qemu-system-riscv64 \
     $DEBUG_GDB \
     $DEBUG_CPU \
@@ -60,18 +59,16 @@ exec qemu-system-riscv64 \
     -machine virt \
     -device virtio-rng-pci \
     $TRAP_COMPRESSED \
-    $CUSTOM_BIOS \
-    -netdev user,id=net0,hostfwd=tcp::60022-:22 -device virtio-net-device,netdev=net0 \
+    -netdev user,id=net0,hostfwd=tcp::60022-:22 \
+    -device virtio-net-device,netdev=net0 \
     -virtfs local,path=/nix/store,security_model=none,mount_tag=nix-store \
     -virtfs local,path="${SHARED_DIR:-$TMPDIR/xchg}",security_model=none,mount_tag=shared \
     -virtfs local,path="$TMPDIR"/xchg,security_model=none,mount_tag=xchg \
-    -device virtio-keyboard \
     -drive "file=$NIX_DISK_IMAGE,if=none,id=hd0" \
     -device virtio-blk-device,drive=hd0 \
-    -device loader,addr=0x84000000,file=$system/kernel \
     -kernel $system/kernel \
     -initrd $system/initrd \
-    -append "$(cat $system/kernel-params) init=$system/init console=ttyS0,115200n8 loglevel=7 $QEMU_KERNEL_PARAMS" 
+    -append "$(cat $system/kernel-params) init=$system/init console=ttyS0,115200n8 loglevel=7 $QEMU_KERNEL_PARAMS" \
     $QEMU_OPTS \
     "$@"
 

flake.nix

@@ -18,6 +18,7 @@
         system = "${system}";
         modules = [
           ./configuration.nix
+          ./lagarto-ox.nix
           ./vm.nix
         ];
       };
@@ -54,6 +55,18 @@
           ./no-compressed.nix
         ];
       };
+
+      # QEMU configuration (x86 host) for a FPGA Lagarto Ox CPU virtual machine
+      qemu-lagarto-ox = nixosSystem {
+        specialArgs = { inherit self; };
+        system = "${system}";
+        modules = [
+          ./configuration.nix
+          ./lagarto-ox.nix
+          ./no-compressed.nix
+          ./vm.nix
+        ];
+      };
     };
 
     # A development shell with QEMU ready to boot the RISC-V system in an x86
@@ -131,6 +144,39 @@
       '';
     };
 
+    devShells.x86_64-linux.qemu-lagarto-ox =
+    let
+      nixosconf = self.nixosConfigurations.qemu-lagarto-ox;
+      syspkgs = nixosconf.pkgs;
+      build = nixosconf.config.system.build;
+    in syspkgs.mkShell rec {
+      pname = "lagarto-ox-shell";
+      nativeBuildInputs = with syspkgs; [ qemu_full ];
+      COMMIT = if self ? rev then self.rev else "dirty";
+      TOPLEVEL = build.toplevel;
+      OPENSBI = syspkgs.opensbi;
+      KERNEL = build.kernel;
+      INITRD = build.initialRamdisk;
+      UBOOT_ENV = syspkgs.uboot-env;
+      BITSTREAM = syspkgs.bitstream;
+      BOOTROM = syspkgs.bootrom;
+      GCROOT = mkRoots syspkgs [
+        syspkgs.stdenv KERNEL OPENSBI syspkgs.riscv-tools
+      ];
+      shellHook = ''
+        echo "Here are the current system pieces:"
+        echo " COMMIT    = $COMMIT"
+        echo " TOPLEVEL  = $TOPLEVEL"
+        echo " KERNEL    = $KERNEL"
+        echo " OPENSBI   = $OPENSBI"
+        echo " INITRD    = $INITRD"
+        echo " UBOOT_ENV = $UBOOT_ENV"
+        echo " BITSTREAM = $BITSTREAM"
+        echo " BOOTROM   = $BOOTROM"
+        echo " GCROOT    = $GCROOT"
+      '';
+    };
+
     devShells.x86_64-linux.lagarto-ox-rd =
     let
       nixosconf = self.nixosConfigurations.lagarto-ox;

vm.nix

@@ -8,7 +8,9 @@
   ];
 
   # Enable ssh on boot
-  services.openssh.enable = true;
+  services.openssh.enable = lib.mkForce true;
+  networking.dhcpcd.enable = lib.mkForce true;
+  services.timesyncd.enable = lib.mkForce true;
 
   boot = {
     kernelParams = [
@@ -47,8 +49,8 @@
         INET y
         NETWORK_FILESYSTEMS y
         OVERLAY_FS y
-        #"9P_FS" y
-        #"9P_FS_POSIX_ACL" y
+        9P_FS y
+        9P_FS_POSIX_ACL y
         PCI y
         VIRTIO_PCI y
         PCI_HOST_GENERIC y
@@ -63,16 +65,6 @@
 
   nixpkgs.overlays = [
     (final: prev: {
-      qemu = prev.qemu.override {
-        pulseSupport = false;
-        pipewireSupport = false;
-        sdlSupport = false;
-        jackSupport = false;
-        gtkSupport = false;
-        vncSupport = false;
-        smartcardSupport = false;
-      };
-
       uboot-custom = prev.ubootQemuRiscv64Smode.override {
         # Override preboot to set 'bootcmd' directly to the kernel address in RAM
         extraConfig = ''