On 06.08.25 11:48, Julien Grall wrote:
Hi Grygorii,
On 06/08/2025 09:19, Grygorii Strashko wrote:
Hi Julien,
On 06.08.25 00:07, Julien Grall wrote:
Hi Grygorii,
On 05/08/2025 20:00, Grygorii Strashko wrote:
From: Grygorii Strashko <grygorii_stras...@epam.com>
Call stack for dom0less hwdom case (1:1) memory:
create_domUs
|-construct_domU
|-construct_hwdom()
|-allocate_memory_11()
And allocate_memory_11() uses "dom0_mem" as:
min_low_order =
get_order_from_bytes(min_t(paddr_t, dom0_mem, MB(128)));
In case of dom0less boot the "dom0_mem" is not used and defaulted to 0,
From docs/mics/xen-command-linux.pandoc:
---
### dom0_mem (ARM)
> `= <size>`
Set the amount of memory for the initial domain (dom0). It must be
greater than zero. This parameter is required.
---
If dom0_mem is effectively optional, then shouldn't the doc be updated?
No. I think doc is correct because when regular Dom0(hwdom)(initial domain)
is created code goes through regular Dom0 path and "dom0_mem" is accounted for.
I understand this is used when dom0 is not described in the device tree.
The crucial part in your sentence is "when", to me this indicates a condition. Whereas
the current wording in xen-command-linux is using "required" with no condition. So a
reader can rightfully think the parameter is also used in dom0less and have to be specified.
So I think the wording needs to be tweaked to something like "This parameter is
required (and only used) when the initial domain is not described in the
Device-Tree."
Got it.
Although, "required" might still be too strict because it looks like we would
provide a configuration for dom0_mem if it is not set.
Correct - it will be defaulted to MB(512) if not configured + log notification
"PLEASE SPECIFY dom0_mem PARAMETER - USING 512M FOR NOW\n"
Thank you.
--
Best regards,
-grygorii
