Re: [patch RFC 24/38] x86/xen: Consolidate XEN-MSI init

[Jürgen Groß]

On 21.08.20 02:24, Thomas Gleixner wrote:
> X86 cannot store the irq domain pointer in struct device without breaking
> XEN because the irq domain pointer takes precedence over arch_*_msi_irqs()
> fallbacks.
>
> To achieve this XEN MSI interrupt management needs to be wrapped into an
> irq domain.
>
> Move the x86_msi ops setup into a single function to prepare for this.
>
> Signed-off-by: Thomas Gleixner<tglx@xxxxxxxxxxxxx>
> ---
>   arch/x86/pci/xen.c |   51 ++++++++++++++++++++++++++++++++-------------------
>   1 file changed, 32 insertions(+), 19 deletions(-)
>
> --- a/arch/x86/pci/xen.c
> +++ b/arch/x86/pci/xen.c
> @@ -371,7 +371,10 @@ static void xen_initdom_restore_msi_irqs
>   		WARN(ret && ret != -ENOSYS, "restore_msi -> %d\n", ret);
>   	}
>   }
> -#endif
> +#else /* CONFIG_XEN_DOM0 */
> +#define xen_initdom_setup_msi_irqs	NULL
> +#define xen_initdom_restore_msi_irqs	NULL
> +#endif /* !CONFIG_XEN_DOM0 */
>   
>   static void xen_teardown_msi_irqs(struct pci_dev *dev)
>   {
> @@ -403,7 +406,31 @@ static void xen_teardown_msi_irq(unsigne
>   	WARN_ON_ONCE(1);
>   }
>   
> -#endif
> +static __init void xen_setup_pci_msi(void)
> +{
> +	if (xen_initial_domain()) {
> +		x86_msi.setup_msi_irqs = xen_initdom_setup_msi_irqs;
> +		x86_msi.teardown_msi_irqs = xen_teardown_msi_irqs;
> +		x86_msi.restore_msi_irqs = xen_initdom_restore_msi_irqs;
> +		pci_msi_ignore_mask = 1;

This is wrong, as a PVH initial domain shouldn't do the pv settings.

The "if (xen_initial_domain())" should be inside the pv case, like:

if (xen_pv_domain()) {
	if (xen_initial_domain()) {
		...
	} else {
		...
	}
} else if (xen_hvm_domain()) {
	...

Juergen