On 20.10.2025 15:26, Teddy Astie wrote: > Le 01/09/2025 à 17:50, Jan Beulich a écrit : >> On 29.08.2025 15:32, Teddy Astie wrote: >>> Le 28/08/2025 à 14:30, Jan Beulich a écrit : >>>> On 21.08.2025 17:25, Teddy Astie wrote: >>>>> --- a/xen/include/public/arch-x86/hvm/start_info.h >>>>> +++ b/xen/include/public/arch-x86/hvm/start_info.h >>>>> @@ -99,6 +99,13 @@ >>>>> #define XEN_HVM_MEMMAP_TYPE_DISABLED 6 >>>>> #define XEN_HVM_MEMMAP_TYPE_PMEM 7 >>>>> >>>>> +/* Xen-specific types (OEM-specific range of the ACPI spec) */ >>>>> +#define XEN_HVM_MEMMAP_TYPE_SHARED_INFO 0xF0000001 /* Shared info page >>>>> */ >>>>> +#define XEN_HVM_MEMMAP_TYPE_GRANT_TABLE 0xF0000002 /* Grant table >>>>> pages */ >>>>> +#define XEN_HVM_MEMMAP_TYPE_GNTTAB_STATUS 0xF0000003 /* Grant table >>>>> status page (v2) */ >>>>> +#define XEN_HVM_MEMMAP_TYPE_FOREIGN_REG 0xF0000004 /* Suitable region >>>>> for grant mappings */ >>>>> + /* and foreign >>>>> mappings */ >>>> >>>> I question it being legitimate for us to introduce new E820 types. >>> >>> These E820 types are (at least in ACPI specification) in the OEM-defined >>> range which seems appropriate for me to use for Xen-specific mappings. >> >> Just that we're not an OEM. > > How should such information be provided alternatively ? > > Currently, premapped pages (xenstore, PV console, ...) locations are > provided through hvm parameters, but I don't think introducing new hvm > parameters is very wise. > > One way of another, we would need to provide to the guest a xen-specific > memory map for implementing this.
Yes, I don't think there's a way around something custom. (I am, btw, also not overly happy about seeing "fixed memory layout" appear in the first place.) Jan
