[vfio-users] Windows 7 successfully migrated from BIOS to OVMF/UEFI

[Laszlo Ersek]

On 05/16/16 11:46, Blank Field wrote:
> 
> On May 16, 2016 12:27 PM, "Leonhard Preis" <leonhard at pre.is
> <mailto:leonhard at pre.is>> wrote:
>>
>> My dear fellow vfio users,
>>
>> today I want to share my success[1] with you. In case you have Windows
> 7 and currently use BIOS but would like to switch to UEFI or are about
> to set up your first Windows VM with passthrough and would prefer
> Windows 7 over Windows 8 and above, rejoice: It’s working just fine.
> ~A lot of text cut.
> 
> Windows 7 has an EFI compatible bootloader, but the OS doesn't support
> GOP, using VBE when there are no drivers installed.
> Thanks to edk2 dev team, we have a shim which captures all VBE actions
> and pushes them to QXL even without CSM enabled.
> Since you are migrating, your installation already has drivers
> installed, so all this stuff is hidden from you.

It's refreshing to read this.

... I think Alex's sentence (and I'm quoting it from the OP's email, not
straight from Alex's blog)

    AFAIK, Windows 7 does not support UEFI natively, requiring the CSM
    (Compatibility Support Module) which I believe defeats the purpose
    of using UEFI.

is accurate. The only thing I might suggest, perhaps, would be a
footnote saying

    But, for '-vga std' and '-vga qxl', OVMF makes Windows 7 work even
    without a CSM (only in 1024x768x32, until native drivers are
    installed for the assigned GPU or for QXL), thanks to the hack that
    is "OvmfPkg/QemuVideoDxe/VbeShim.*".

Thanks
Laszlo

> Second - you do NOT need to flash your GPU for two reasons:
> 1. you have installed the drivers already, they don't care about GOP,
> EFI, VBE, CSM...
> 2. you can just append it via options in the command line or in libvirt xml.
> 
> There are numerous ways to install or "migrate" W7 to UEFI, your GPU
> actually doesn't actually need to have an EFI driver in its' ROM.
> 
> Moreover, if there is no ROM available, you can craft it manually by
> taking an old-but-working efi driver from some other card's ROM and
> appending it to your card's ROM using EfiRom from edk2-tools.
> I've seen a presentation from amd dating back to 2011 saying that all
> EFI drivers providing GOP will be universal, and they are now.
> 
> Please note that some versions of it are broken, for example ASUS
> HD7750-DCSL-1 which i have.
> 
> This all was talked over on archlinux forum.
> 
> 
> 
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