On 2025-03-07 03:31, Julien Grall wrote:
Hi,
On 06/03/2025 22:03, Jason Andryuk wrote:
Assign domid 0 to the hwdom. Normally, dom0less does not use domid 0.
A few years ago, we went to great length to avoid making the assumption
that the hardware domain is domid 0. See all the calls to
"is_hardware_domain()". So I am reluctant to force the domain ID to 0.
I was disappointed when it didn't "just work".
This fixes using the Xen console which assumes domid 0 to use the
hypercall interface.
I had a brief look at drivers/char/console.c and I can't find any place
assuming "domid 0". Do you have any pointer?
As Jan pointed out, Denis Mukhin's patch removed the domid 0 assumption.
This was developed without this patch when it mattered.
I tested before posting without this patch (and with Denis's), and again
now, and I didn't get a hwdom login. Turns out xenstored was assuming
domid 0. Changing that with --master-domid gets to the login prompt.
Still, there are now other userspace errors. xen-init-dom0 hardcodes
domid 0 which doesn't exist. init-dom0less only initializes
non-introduced domains, so hwdom doesn't get its "domid" xenstore node
populated. That leads to other errors.
So I think with Denis's patch, this isn't strictly needed. It does help
existing toolstack code work today.
Regards,
Jason
