Re: Failed to start qemu-system-aarch64 virt: qemu-system-aarch64: device requires ... bytes, block backend provides

[Peter Maydell]

On Thu, 9 Mar 2023 at 15:28, Alyosha Shevandin <shevandin_al@hotmail.com> wrote:
>
> Hi,
> I'm trying ti start virt emulation and fails with the follow error:
> qemu-system-aarch64: device requires 67108864 bytes, block backend provides 
> 1112576 bytes
>
> What exactly does it mean and what could be done to prevent it?
> I start it with the follow command line parameters:
> qemu-system-aarch64 -nographic -machine virt,secure=on -cpu cortex-a55 -smp 
> clusters=1,cores=1 -m 1024 -bios bl.bin semihosting-config 
> enable=on,target=native -drive if=pflash,file=fip.bin,format=raw,unit=1

The message means that the device you were trying to set up requires
an image of exactly 64K in size, but the file you provided it
(fip.bin in this case) is too small. You can fix this by
padding out your image file with zeroes to be 64K in size.

(The reason for this restriction is to deal with the
question of "what happens if the guest writes to the last
byte of the 64K flash device?". If the backing image is
too small there's nowhere for QEMU to put that data.)

thanks
-- PMM