On 16.01.2024 20:25, Elias El Yandouzi wrote:
> From: Wei Liu <wei.l...@citrix.com>
>
> Xen shouldn't use domheap page as if they were xenheap pages. Map and
> unmap pages accordingly.
The title could to with mentioning Dom0. Since it's already a little long,
the mentioning of domheap pages could be left to the description. E.g.
"map pages while relocating Dom0 initrd"?
> --- a/xen/arch/x86/pv/dom0_build.c
> +++ b/xen/arch/x86/pv/dom0_build.c
> @@ -615,18 +615,25 @@ int __init dom0_construct_pv(struct domain *d,
> if ( d->arch.physaddr_bitsize &&
> ((mfn + count - 1) >> (d->arch.physaddr_bitsize - PAGE_SHIFT)) )
> {
> + unsigned long nr_pages;
> +
> order = get_order_from_pages(count);
> page = alloc_domheap_pages(d, order, MEMF_no_scrub);
> if ( !page )
> panic("Not enough RAM for domain 0 initrd\n");
> +
> + nr_pages = 1UL << order;
Nit: Is there anything wrong with making this the initializer of the
variable?
> for ( count = -count; order--; )
> if ( count & (1UL << order) )
> {
> free_domheap_pages(page, order);
> page += 1UL << order;
> + nr_pages -= 1UL << order;
> }
> - memcpy(page_to_virt(page), mfn_to_virt(initrd->mod_start),
> - initrd_len);
> +
> + for ( i = 0; i < nr_pages; i++ )
> + copy_domain_page(page_to_mfn(page + i), _mfn(initrd_mfn +
> i));
There's a type discrepancy between "i" and "nr_pages". If we truly expect
initrd-s of more than 16Tb size, "nr_pages" indeed needs to be unsigned
long, but then "i" can't remain as int. I for one think that having
"nr_pages" be unsigned int is more than enough. It might then still be
good to switch "i" from plain int to unsigned int, albeit maybe in a
(tiny) separate patch.
I further wonder whether it wouldn't be more consistent with the "else"
branch of the containing "if()" if instead of "initrd_mfn" "mfn" would
be used here (and incremented as we go). At which point I think the use
of "i" could be avoided here altogether:
for ( ; nr_pages--; page++, mfn++ )
copy_domain_page(page_to_mfn(page), _mfn(mfn));
or something substantially similar (e.g. re-written as while() loop).
Jan
