On 31/05/2019 02:35, Jan Beulich wrote:
> @@ -516,6 +521,36 @@ struct domain *domain_create(domid_t dom
> return ERR_PTR(err);
> }
>
> +void __init setup_special_domains(void)
> +{
> + /*
> + * Initialise our DOMID_XEN domain.
> + * Any Xen-heap pages that we will allow to be mapped will have
> + * their domain field set to dom_xen.
> + * Hidden PCI devices will also be associated with this domain
> + * (but be [partly] controlled by Dom0 nevertheless).
> + */
> + dom_xen = domain_create(DOMID_XEN, NULL, false);
> + BUG_ON(IS_ERR(dom_xen));
I know this is copying code like-for-like, but this error handling is
terrible in practice.
Even just:
if ( IS_ERR(dom_xen) )
panic("Failed to create dom_xen: %d\n", PTR_ERR(dom_xen));
would be an improvement.
> +#ifdef CONFIG_HAS_PCI
> + INIT_LIST_HEAD(&dom_xen->arch.pdev_list);
> +#endif
The position of this identifies that we've got obviously got bugs
(perhaps latent) elsewhere, seeing as other special domains don't get
working constructs such as list_empty().
In the code which currently exists, I can't spot it ever being touched
for ARM, but it is constructed for all non-special x86 guests at the top
of arch_domain_create().
I think the best option, given the #ifdef here, is to reposition the
pdev fields into struct domain, rather than arch_domain, and have this
code fragment near the top of domain_create() where special domains will
all be covered.
~Andrew
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