Re: [PATCH 1/2] xen/cpupool: Reject attempts to add a domain to CPUPOOLID_NONE

[Juergen Gross <jgross@xxxxxxxx>]

On 17.05.22 21:41, Andrew Cooper wrote:
> c/s cfc52148444f ("xen/domain: Reduce the quantity of initialisation for
> system domains") removed the path in domain_create() which called
> sched_init_domain() with CPUPOOLID_NONE for system domains.
>
> Arguably, that changeset should have cleaned up this path too.
>
> However, c/s 92ea9c54fc81 ("arm/dom0less: assign dom0less guests to cpupools")
> changed domain_create() from using a hardcoded poolid of 0, to using a value
> passed by the toolstack.
>
> While CPUPOOLID_NONE is an internal constant, userspace can pass -1 for the
> cpupool_id parameter and attempt to construct a real domain using default ops,
> which at a minimum will fail the assertion in dom_scheduler().
>
> Fixes: 92ea9c54fc81 ("arm/dom0less: assign dom0less guests to cpupools")
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Juergen Gross <jgross@xxxxxxxx>


Juergen

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