Re: [Qemu-devel] [PATCH 1/1] tests: Add migration test for aarch64

[Wei Huang <wei@redhat.com>]

On 10/04/2018 10:07 AM, Philippe Mathieu-Daudé wrote:
> On 28/09/2018 21:47, Wei Huang wrote:
> [...]> +++ b/tests/migration/aarch64/Makefile
>> @@ -0,0 +1,20 @@
>> +# To specify cross compiler prefix, use CROSS_PREFIX=
>> +#   $ make CROSS_PREFIX=aarch64-linux-gnu-
>> +
>> +.PHONY: all clean
>> +all: a-b-kernel.h
>> +
>> +a-b-kernel.h: aarch64.kernel
>> +	echo "$$__note" > header.tmp
> 
> This won't work on a read-only fs.

Under which setting? If tmp file can't be generated on a read-only fs,
wouldn't $@ have the same problem?

> 
> Why don't you use $@ directly?
> 
>> +	xxd -i $< | sed -e 's/.*int.*//' >> header.tmp
> 
> Please use:
> 
> xxd -g4 ...

This option doesn't work with -i (the include file style output) which
is what we want. From xxd manual:

"-g bytes | -groupsize bytes
    separate the output of every <bytes> bytes (two hex characters or
    eight bit-digits each) by a whitespace. Specify -g 0 to suppress
    grouping.  <Bytes> defaults to 2 in normal mode and 1 in bits
    mode. Grouping does not apply to postscript or include style."


> 
> xxd might not be installed on the host.

xxd is provided by vim packages. So it should be available in most distros.

> 
> That said we should however install it on the docker cross images.

Agreed.

> 
>> +	mv header.tmp $@
>> +
>> +aarch64.kernel: aarch64.elf
>> +	$(CROSS_PREFIX)objcopy -O binary $< $@
>> +
>> +aarch64.elf: a-b-kernel.S
>> +	$(CROSS_PREFIX)gcc -o $@ -nostdlib -Wl,--build-id=none $<
>> +
>> +clean:
>> +	@rm -rf *.kernel *.elf
>