Re: [PATCH v5 09/16] kexec: enable KHO support for memory preservation

[Jason Gunthorpe]

On Wed, Apr 02, 2025 at 07:16:27PM +0000, Pratyush Yadav wrote:
> > +int kho_preserve_phys(phys_addr_t phys, size_t size)
> > +{
> > +	unsigned long pfn = PHYS_PFN(phys), end_pfn = PHYS_PFN(phys + size);
> > +	unsigned int order = ilog2(end_pfn - pfn);
> 
> This caught my eye when playing around with the code. It does not put
> any limit on the order, so it can exceed NR_PAGE_ORDERS. Also, when
> initializing the page after KHO, we pass the order directly to
> prep_compound_page() without sanity checking it. The next kernel might
> not support all the orders the current one supports. Perhaps something
> to fix?

IMHO we should delete the phys functions until we get a user of them

Jason