Re: [Xen-devel] [PATCH v2] xen: arm: Update arm64 image header

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Wed, Jun 22, 2016 at 03:44:44PM +0200, Dirk Behme wrote:
> On 22.06.2016 15:30, Konrad Rzeszutek Wilk wrote:
> >On Wed, Jun 22, 2016 at 10:59:19AM +0200, Dirk Behme wrote:
> >>With the Linux kernel commits
> >>
> >>https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/Documentation/arm64/booting.txt?id=4370eec05a887b0cd4392cd5dc5b2713174745c0
> >>
> >>https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/Documentation/arm64/booting.txt?id=a2c1d73b94ed49f5fac12e95052d7b140783f800
> >>
> >>the arm64 image header changed. While the size of the header isn't changed,
> >>some members have changed their usage.
> >>
> >>Update Xen to this updated image header.
> >>
> >>The main changes are that the first magic is gone and that there is an
> >>image size, now.
> >>
> >>In case we read a size != 0, let's use this image size, now. This does
> >>allow us to check if the kernel Image is larger than the size given in
> >>the device tree, too.
> >>
> >>Additionally, add an error message if the magic is not found. This might
> >>be the case with kernel's < 3.12 prior to
> >
> >Don't you want to still check for those kernels and use them?
> 
> 
> Please check the _existing_ code: It's
> 
> 
> if ( zimage.magic0 != ZIMAGE64_MAGIC_V0 &&
>      zimage.magic1 != ZIMAGE64_MAGIC_V1 )
>   return -EINVAL;

Oh, indeed!
> 
> 
> My patch doesn't change anything regarding the fact that if the magics are
> not valid (due to quite old kernel version) the code does exit with an
> error.

/me nods
> 
> While the review of v1 of this patch, Julien asked for an error message to
> be added here. Fine.
> 
> But if there is the request to change the behavior regarding which kernels
> are supported I'd think that this is independent on this patch and should be
> done in an additional patch.

Right, and I think it is fine to skip that  - because as you say - it
already ignores older kernels.

Your comment in the description threw me off. Could you kindly update it to say
"This does not change the behavior - we had been failing kernels older
than 3.12 before - but without any error messages." or such?

Thanks!

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