Merge branch '2023-08-24-enable-more-features-in-qemu-arm' into next

To quote the author:
Now that the driver for the Bochs VGA card emulated by QEMU is no longer
limited to x86 architectures, this series enables it on arm and arm64 virtual
machines to provide a graphical interface. In line with that series this also
enables console buffering and USB keyboard.

Tested with the Debian 12 installer using GRUB EFI:

  $ tools/buildman/buildman -o build/qemu_arm64 --boards=qemu_arm64 -w
  $ cd build/qemu_arm64
  $ curl -L -o debian.img \
      https://cdimage.debian.org/debian-cd/current/arm64/iso-cd/debian-12.0.0-arm64-netinst.iso
  $ qemu-system-aarch64 \
      -machine virt -cpu cortex-a53 -m 4G -smp 4 \
      -bios u-boot.bin \
      -serial stdio -device VGA \
      -nic user,model=virtio-net-pci \
      -device virtio-rng-pci \
      -device qemu-xhci,id=xhci -device usb-kbd -device usb-tablet \
      -drive if=virtio,file=debian.img,format=raw,readonly=on,media=cdrom

And with one using extlinux.conf:

    $ [...]
    $ curl -L -o head.img.gz \
        https://deb.debian.org/debian/dists/bookworm/main/installer-arm64/current/images/netboot/SD-card-images/gtk/firmware.none.img.gz
    $ curl -L -o partition.img.gz \
        https://deb.debian.org/debian/dists/bookworm/main/installer-arm64/current/images/netboot/SD-card-images/gtk/partition.img.gz
    $ zcat head.img.gz partition.img.gz >debian.img
    $ [...]

Both can get to a graphical installer just fine, in addition to U-Boot
video console showing up in a GTK window.

1 files changed, 76 insertions, 0 deletions

diff --git a/doc/board/emulation/qemu-arm.rst b/doc/board/emulation/qemu-arm.rst
index b42d924cc66..78bcc3ee44c 100644
--- a/doc/board/emulation/qemu-arm.rst
+++ b/doc/board/emulation/qemu-arm.rst
@@ -67,6 +67,10 @@ Additional persistent U-Boot environment support can be added as follows:
 Additional peripherals that have been tested to work in both U-Boot and Linux
 can be enabled with the following command line parameters:
 
+- To add a video console, remove "-nographic" and add e.g.::
+
+    -serial stdio -device VGA
+
 - To add a Serial ATA disk via an Intel ICH9 AHCI controller, pass e.g.::
 
     -drive if=none,file=disk.img,format=raw,id=mydisk \
@@ -80,6 +84,10 @@ can be enabled with the following command line parameters:
 
     -device usb-ehci,id=ehci
 
+- To add a USB keyboard attached to an emulated xHCI controller, pass e.g.::
+
+    -device qemu-xhci,id=xhci -device usb-kbd,bus=xhci.0
+
 - To add an NVMe disk, pass e.g.::
 
     -drive if=none,file=disk.img,id=mydisk -device nvme,drive=mydisk,serial=foo
@@ -90,6 +98,74 @@ can be enabled with the following command line parameters:
 
 These have been tested in QEMU 2.9.0 but should work in at least 2.5.0 as well.
 
+Booting distros
+---------------
+
+It is possible to install and boot a standard Linux distribution using
+qemu_arm64 by setting up a root disk::
+
+    qemu-img create root.img 20G
+
+then using the installer to install. For example, with Debian 12::
+
+    qemu-system-aarch64 \
+      -machine virt -cpu cortex-a53 -m 4G -smp 4 \
+      -bios u-boot.bin \
+      -serial stdio -device VGA \
+      -nic user,model=virtio-net-pci \
+      -device virtio-rng-pci \
+      -device qemu-xhci,id=xhci \
+      -device usb-kbd -device usb-tablet \
+      -drive if=virtio,file=debian-12.0.0-arm64-netinst.iso,format=raw,readonly=on,media=cdrom \
+      -drive if=virtio,file=root.img,format=raw,media=disk
+
+The output will be something like this::
+
+    U-Boot 2023.10-rc2-00075-gbe8fbe718e35 (Aug 11 2023 - 08:38:49 +0000)
+
+    DRAM:  4 GiB
+    Core:  51 devices, 14 uclasses, devicetree: board
+    Flash: 64 MiB
+    Loading Environment from Flash... *** Warning - bad CRC, using default environment
+
+    In:    serial,usbkbd
+    Out:   serial,vidconsole
+    Err:   serial,vidconsole
+    Bus xhci_pci: Register 8001040 NbrPorts 8
+    Starting the controller
+    USB XHCI 1.00
+    scanning bus xhci_pci for devices... 3 USB Device(s) found
+    Net:   eth0: virtio-net#32
+    Hit any key to stop autoboot:  0
+    Scanning for bootflows in all bootdevs
+    Seq  Method       State   Uclass    Part  Name                      Filename
+    ---  -----------  ------  --------  ----  ------------------------  ----------------
+    Scanning global bootmeth 'efi_mgr':
+    Scanning bootdev 'fw-cfg@9020000.bootdev':
+    fatal: no kernel available
+    scanning bus for devices...
+    Scanning bootdev 'virtio-blk#34.bootdev':
+      0  efi          ready   virtio       2  virtio-blk#34.bootdev.par efi/boot/bootaa64.efi
+    ** Booting bootflow 'virtio-blk#34.bootdev.part_2' with efi
+    Using prior-stage device tree
+    Failed to load EFI variables
+    Error: writing contents
+    ** Unable to write file ubootefi.var **
+    Failed to persist EFI variables
+    Missing TPMv2 device for EFI_TCG_PROTOCOL
+    Booting /efi\boot\bootaa64.efi
+    Error: writing contents
+    ** Unable to write file ubootefi.var **
+    Failed to persist EFI variables
+    Welcome to GRUB!
+
+Standard boot looks through various available devices and finds the virtio
+disks, then boots from the first one. After a second or so the grub menu appears
+and you can work through the installer flow normally.
+
+After the installation, you can boot into the installed system by running QEMU
+again without the drive argument corresponding to the installer CD image.
+
 Enabling TPMv2 support
 ----------------------