On 6/21/23 02:15, Borislav Petkov wrote: > On Mon, Jun 12, 2023 at 08:34:02AM -0700, Dave Hansen wrote: >> On 6/11/23 21:25, Michael Roth wrote: >>> + /* >>> + * Calculate the amount the memory that must be reserved by the BIOS to >>> + * address the whole RAM, including the bookkeeping area. The RMP itself >>> + * must also be covered. >>> + */ >>> + max_rmp_pfn = max_pfn; >>> + if (PHYS_PFN(rmp_end) > max_pfn) >>> + max_rmp_pfn = PHYS_PFN(rmp_end); >> Could you say a little here about how this deals with memory hotplug? > Does SNP hw even support memory hotplug? > > I think in order to support that, you'd need some special dance because > of the RMP table etc... Yep, there's the hardware side and then there are fun nuggets like using mem= and then doing a software-only hot-add later after boot. Also, if the hardware doesn't support any kind of hotplug, it would be great to point to the place in the spec where it says that.