Hi Marc,
On 10/20/22 5:44 PM, Marc Zyngier wrote:
On Thu, 20 Oct 2022 00:57:32 +0100,
Gavin Shan <gs...@redhat.com> wrote:
For Marc's suggestion to add properties so that these high memory
regions can be disabled by users. I can add one patch after this one
to introduce the following 3 properties. Could you please confirm
the property names are good enough? It's nice if Marc can help to
confirm before I'm going to work on next revision.
"highmem-ecam": "on"/"off" on vms->highmem_ecam
"highmem-mmio": "on"/"off" on vms->highmem_mmio
"highmem-redists": "on"/"off" on vms->highmem_redists
I think that'd be reasonable, and would give the user some actual
control over what gets exposed in the highmem region.
I guess that the annoying thing with these options is that they allow
the user to request conflicting settings (256 CPUs and
highmem-redists=off, for example). You'll need to make this fail more
or less gracefully.
Thanks for the quick confirm. The check is already existing in machvirt_init().
I think what we need is simply to calculate 'virt_max_cpus' with consideration
to 'highmem-redists' property there.
if (max_cpus > virt_max_cpus) {
error_report("Number of SMP CPUs requested (%d) exceeds max CPUs "
"supported by machine 'mach-virt' (%d)",
max_cpus, virt_max_cpus);
exit(1);
}
Thanks,
Gavin
