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()".
Cheers,
--
Julien Grall
