Re: [Qemu-devel] [PATCH v8 47/54] Round up RAMBlock sizes to host page sizes

[Juan Quintela]

"Dr. David Alan Gilbert (git)" <address@hidden> wrote:
> From: "Dr. David Alan Gilbert" <address@hidden>
>
> RAMBlocks that are not a multiple of host pages in length
> cause problems for postcopy (I've seen an ACPI table on aarch64
> be 5k in length - i.e. 5x target-page), so round RAMBlock sizes
> up to a host-page.
>
> This potentially breaks migration compatibility due to changes
> in RAMBlock sizes; however:
>    1) x86 and s390 I think always have host=target page size
>    2) When I've tried on Power the block sizes already seem aligned.
>    3) I don't think there's anything else that maintains per-version
>       machine-types for compatibility.
>
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>

Reviewed-by: Juan Quintela <address@hidden>

We had this problem on the past when we moved the machines to be
Megabyte rounded size, some machines where not.  But in this particular
case, I will clame that having a size that is _not_ of the size of the
host pages is just asking for trouble.