[PATCH RESEND kvmtool 0/4] arm: Payload memory layout change

[Will Deacon]

On Thu, Nov 28, 2024 at 03:12:42PM +0000, Alexandru Elisei wrote:
> (resending because I accidently only sent the cover letter, sorry for that)
> 
> The first 3 patches are fixes to kvm__arch_load_kernel_image(). I've CC'ed
> the riscv maintainer because it looks to me like riscv is similarly
> affected.
> 
> Patch #4 ("arm64: Increase the payload memory region size to 512MB") might
> be controversial. Follows a bug report I received from Abdollahi Sina in
> private. Details in the commit message, but the gist of the patch is that
> the memory region where kernel + initrd + DTB are copied to are changed
> from 256MB to 512MB.  As a result, the DTB and initrd are moved from below
> ram_start + 256MB to ram_start + 512MB to accomodate a larger initrd.  If
> users rely on finding the DTB and initrd at the current addresses, then I'm
> not sure the patch is justified - after all, if someone really wants to use
> such a large initrd instead of a disk image with virtio, then replacing
> SZ_256M with SZ_512M locally doesn't look like a big ask.
> 
> On the other hand, if there are no users that rely on the current payload
> layout, increasing the memory region size to 512MB to allow for more
> unusual use cases, while still maintaining compatibility with older
> kernels, doesn't seem unreasonable to me.
> 
> Please comment, I don't feel strongly either way - I'll happy drop the last
> patch if there are objections.

Well, I won't reject an imperial.ac.uk patch on a hunch, so let's go for
the whole lot and see if anybody complains!

I'll fix the indentation issue spotted by Drew when applying (thanks!).

Will