Fixes needed for running fedora linux distribution on aarch64

[afbjorklund]

The distribution uses BIOS for x86_64 and UEFI for aarch64, so needs to fallback gracefully.

There was also some problem with the old param, fixed in https://wiki.debian.org/Arm64Qemu

Tested on the Raspberry Pi.

Hopefully also works on M1 ?

Closes #327

Closes #328

[jandubois]

The logic seems more correct after this PR (the original code said it would ignore legacyBIOS on aarch64, but didn't).

I've also tested this PR on M1, and it works there as well.

I'm unsure what the change from -drive to -bios entails, so I'll leave the final decision to @AkihiroSuda.

[afbjorklund]

See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=922979 for details.

2048	/usr/share/qemu-efi-aarch64/QEMU_EFI.fd
65540	/usr/share/AAVMF/AAVMF_CODE.fd

It was supposed to pad for readonly, but it didn't seem to be happening ?

[jandubois]

Unfortunately it breaks on macOS Intel (using default image):

DEBU[0004] [hostagent] qemu[stderr]: qemu: could not load PC BIOS '/usr/local/share/qemu/edk2-x86_64-code.fd'

[jandubois]

File exists, but can't be loaded via -bios /usr/local/share/qemu/edk2-x86_64-code.fd:

$ ls -ld /usr/local/share/qemu/edk2-x86_64-code.fd
-rw-r--r--  1 jan  admin  3653632 24 Aug 10:36 /usr/local/share/qemu/edk2-x86_64-code.fd

[afbjorklund]

The firmware are actually described in some JSON files...

/usr/share/qemu/firmware/60-edk2-x86_64.json

{
    "description": "UEFI firmware for x86_64, without Secure Boot without SMM, with empty varstore",
    "interface-types": [
        "uefi"
    ],
    "mapping": {
        "device": "flash",
        "executable": {
            "filename": "/usr/share/OVMF/OVMF_CODE.fd",
            "format": "raw"
        },
        "nvram-template": {
            "filename": "/usr/share/OVMF/OVMF_VARS.fd",
            "format": "raw"
        }
    },
    "targets": [
        {
            "architecture": "x86_64",
            "machines": [
                "pc-i440fx-*",
                "pc-q35-*"
            ]
        }
    ],
    "features": [
        "acpi-s3",
        "amd-sev",
        "verbose-dynamic"
    ],
    "tags": [

    ]
}

/usr/share/qemu/firmware/60-edk2-aarch64.json

{
    "description": "UEFI firmware for aarch64",
    "interface-types": [
        "uefi"
    ],
    "mapping": {
        "device": "flash",
        "executable": {
            "filename": "/usr/share/AAVMF/AAVMF_CODE.fd",
            "format": "raw"
        },
        "nvram-template": {
            "filename": "/usr/share/AAVMF/AAVMF_VARS.fd",
            "format": "raw"
        }
    },
    "targets": [
        {
            "architecture": "aarch64",
            "machines": [
                "virt-*"
            ]
        }
    ],
    "features": [
        "verbose-static"
    ],
    "tags": [

    ]
}

So changing the search path for the padded version should work (untested)

[jandubois]

Works on both Intel and Apple macOS again.

Please squash commits (the revert commit is also missing DCO).

[AkihiroSuda]

Thanks