On 18/08/2025 8:57 am, Jan Beulich wrote: > --- a/xen/arch/x86/include/asm/mm.h > +++ b/xen/arch/x86/include/asm/mm.h > @@ -464,6 +464,16 @@ extern bool opt_pv_linear_pt; > ASSERT(((_p)->count_info & PGC_count_mask) != 0); \ > ASSERT(page_get_owner(_p) == (_d)) > > +#define RAM_TYPE_CONVENTIONAL 0x00000001 > +#define RAM_TYPE_RESERVED 0x00000002 > +#define RAM_TYPE_UNUSABLE 0x00000004 > +#define RAM_TYPE_ACPI 0x00000008 > +#define RAM_TYPE_UNKNOWN 0x00000010 > +/* TRUE if the whole page at @mfn is of the requested RAM type(s) above. */ > +bool page_is_ram_type(unsigned long mfn, unsigned long mem_type);
Making it x86-only is fine, but if you're changing the return type, mem_type can become shorter too. Also, I'm struggling to convince myself that page_is_ram_type() is correct. Even if it is correct, it is horribly inefficient, and we run this algorithm lots on boot. Checking the type before the range is the backwards way of doing this, and it can be a binary search because we go out of our way to fix unsorted e820 maps. Finally, acpi_memory_banned() shows that this really isn't the greatest API in the first place. It's explicitly designed to take multiple inputs, but does the wrong thing for its' single caller wanting that behaviour. I can't help but feel we'd be in a better position by removing this entirely and using plain E820 queries. ~Andrew
