Hi Julien, On 06/10/2023 11:43, Julien Grall wrote: > > > On 05/10/2023 21:15, Michal Orzel wrote: >> Hi Julien, > > Hi Michal, > >> On 05/10/2023 18:54, Julien Grall wrote: >>> >>> >>> From: Julien Grall <[email protected]> >>> >>> Per ACPI 6.5 section 5.2.25 ("Generic Timer Description Table (GTDT)"), >>> the fields "Secure EL1 Timer GSIV/Flags" are optional and an OS running >>> in non-secure world is meant to ignore the values. >>> >>> However, Xen is trying to reserve the value. When booting on Graviton >>> 2 metal instances, this would result to crash a boot because the >>> value is 0 which is already reserved (I haven't checked for which device). >> Per my understanding it is not reserved by any device. >> 0 means SGI and for SGIs we pre-reserve the bits in allocated_irqs at the >> very start. > > Ah yes good point. Somehow, I had in mind that PPI was starting at 0 > '^^. How about replacing the paragraph with: > > "However, Xen is trying to reserve the value. The ACPI tables for > Graviton 2 metal instances will provide the value 0 which is not a > correct PPI (PPIs start at 16) and would have in fact been already > reserved by Xen as this is an SGI. Xen will hit the BUG() and panic()". Yes, this sounds better. With that: Reviewed-by: Michal Orzel <[email protected]>
~Michal
