Re: [PATCH] hw/i386/pc_piix: Make piix_intx_routing_notifier_xen() more device independent

[Bernhard Beschow]

Am 9. Januar 2024 08:51:37 UTC schrieb David Woodhouse <dwmw2@infradead.org>:
>On Mon, 2024-01-08 at 00:16 +0100, Bernhard Beschow wrote:
>> This is a follow-up on commit 89965db43cce "hw/isa/piix3: Avoid Xen-specific
>> variant of piix3_write_config()" which introduced
>> piix_intx_routing_notifier_xen(). This function is implemented in board code 
>> but
>> accesses the PCI configuration space of the PIIX ISA function to determine 
>> the
>> PCI interrupt routes. Avoid this by reusing pci_device_route_intx_to_irq() 
>> which
>> makes piix_intx_routing_notifier_xen() more device-agnostic.
>> 
>> One remaining improvement would be making piix_intx_routing_notifier_xen()
>> agnostic towards the number of PCI interrupt routes and move it to xen-hvm.
>> This might be useful for possible Q35 Xen efforts but remains a future 
>> exercise
>> for now.
>> 
>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>
>I'm still moderately unhappy that all this code is written with the
>apparent assumption that there is only *one* IRQ# which is the target
>for a given INTx, when in fact it gets routed to that pin# on the
>legacy PIC and a potentially *different* pin# on the I/O APIC.

Would TYPE_SPLIT_IRQ help in any way?

>
>But you aren't making that worse, so
>
>Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>

Thanks!