On 02.08.2024 10:08, Roger Pau Monné wrote: > On Mon, Jul 08, 2024 at 07:41:21PM +0800, Jiqian Chen wrote: >> Some type of domains don't have PIRQs, like PVH, it doesn't do >> PHYSDEVOP_map_pirq for each gsi. When passthrough a device >> to guest base on PVH dom0, callstack >> pci_add_dm_done->XEN_DOMCTL_irq_permission will fail at function >> domain_pirq_to_irq, because PVH has no mapping of gsi, pirq and >> irq on Xen side. >> What's more, current hypercall XEN_DOMCTL_irq_permission requires >> passing in pirq to set the access of irq, it is not suitable for >> dom0 that doesn't have PIRQs. >> >> So, add a new hypercall XEN_DOMCTL_gsi_permission to grant/deny >> the permission of irq(translate from x86 gsi) to dumU when dom0 >> has no PIRQs. > > I've been wondering about this, and if the hypercall is strictly to > resolve GSIs into IRQs, isn't that the case that Xen identity maps GSI > into the IRQ space, and hence no translation is required?
It was a long-winded discussion to clarify that in obscure cases translation is required: Whenever there's a source override in ACPI. Jan
