Re: Too slow edk2 bios boot?

[Laszlo Ersek <lersek@redhat.com>]

On 06/18/21 15:06, Bin Meng wrote:
> On Fri, Jun 18, 2021 at 7:46 PM Gerd Hoffmann <kraxel@redhat.com> wrote:
> 
>> On Fri, Jun 18, 2021 at 06:46:57PM +0800, Bin Meng wrote:
>>> Hi Laszlo,
>>>
>>> Using the QEMU shipped edk2 bios, for i386, it boots very quickly to
>>> the EFI shell.
>>>
>>> $ qemu-system-i386 -nographic -pflash edk2-i386-code.fd

Ouch. Don't do this. If you use just one pflash chip, then a unified FD file is expected in that chip, containing both varstore and firmware executable.

Upstream QEMU does not bundle / install unified FD files however. What it provides are separate executables and varstore *templates*.

If you don't want to create a permanent variable store file for your VM, from the template called "edk2-i386-vars.fd", then the minimum command line is something like this:

qemu-system-i386 \
  -drive if=pflash,unit=0,format=raw,readonly=on,file=edk2-i386-code.fd \
  -drive if=pflash,unit=1,format=raw,snapshot=on,file=edk2-i386-vars.fd \

(Nowadays I should use the "blockdev" syntax instead of "-drive", but I've not updated my scripts thus far ;))


>>>
>>> However with x86_64, it takes a very long time to boot to the EFI
>>> shell. It seems it got stuck in the PXE boot. Any ideas?
>>
>> One year ago ia32 efi netboot support was dropped (and you are the first
>> who noticed 😎 ).

I certainly noticed:

http://mid.mail-archive.com/e6078611-789f-027b-bea5-759e02b10eee@redhat.com


>>
> 
> I guess not many people play with ia32 these days :)
> 
> 
>>
>> commit 9ed02fbb847277bef88dbe6a677cf3e5f39e5a38
>> Author: Gerd Hoffmann <kraxel@redhat.com>
>> Date:   Wed Jul 22 12:24:35 2020 +0200
>>
>>     ipxe: drop ia32 efi roms
>>
>>     UEFI on ia32 never really took off.  Basically the BIOS -> UEFI shift
>>     came too late, x64 was widespread already, so vendors went from BIOS
>>     straight to UEFI on x64.
>>
>>     Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
>>
>>
>>> I checked the boot manager, and it seems only 64-bit edk2 bios has
>>> built-in PXE boot while 32-bit does not.
>>
>> It isn't edk2 but the nic boot roms, but yes, lack of pxe support on
>> ia32 is the root cause.
>>
> 
> Got it.
> 
> 
>>> Any idea to speed up this whole PXE boot thing?
>>
>> qemu -nic none ?
>>
> 
> Yep this works. Thanks a lot!

If you need neither NICs nor disks in your guest at all, then "-nic none" is indeed the simplest solution.

Thanks,
Laszlo