x86/IO-APIC: fix setup of Xen internally used IRQs

..., i.e. namely that of a PCI serial card with an IRQ above the
legacy range. This had got broken by the switch to cpumask_any() in
cpu_mask_to_apicid_phys(). Fix this by allowing all CPUs for that IRQ
(such that __setup_vector_irq() will properly update a booting CPU's
vector_irq[], avoiding "No irq handler for vector" messages and the
interrupt not working).

While doing this I also noticed that io_apic_set_pci_routing() can't
be quite right: It sets up the destination _before_ getting a vector
allocated (which on other than systems using the flat APIC mode
affects the possible destinations), and also didn't restrict affinity
to ->arch.cpu_mask (as established by assign_irq_vector()).

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/io_apic.c
+++ b/xen/arch/x86/io_apic.c
@@ -2204,6 +2204,7 @@ int io_apic_set_pci_routing (int ioapic,
 {
     struct irq_desc *desc = irq_to_desc(irq);
     struct IO_APIC_route_entry entry;
+    cpumask_t mask;
     unsigned long flags;
     int vector;
 
@@ -2223,8 +2224,6 @@ int io_apic_set_pci_routing (int ioapic,
 
     entry.delivery_mode = INT_DELIVERY_MODE;
     entry.dest_mode = INT_DEST_MODE;
-    SET_DEST(entry.dest.dest32, entry.dest.logical.logical_dest,
-        cpu_mask_to_apicid(TARGET_CPUS));
     entry.trigger = edge_level;
     entry.polarity = active_high_low;
     entry.mask  = 1;
@@ -2240,6 +2239,10 @@ int io_apic_set_pci_routing (int ioapic,
         return vector;
     entry.vector = vector;
 
+    cpumask_and(&mask, desc->arch.cpu_mask, TARGET_CPUS);
+    SET_DEST(entry.dest.dest32, entry.dest.logical.logical_dest,
+             cpu_mask_to_apicid(&mask));
+
     apic_printk(APIC_DEBUG, KERN_DEBUG "IOAPIC[%d]: Set PCI routing entry "
 		"(%d-%d -> %#x -> IRQ %d Mode:%i Active:%i)\n", ioapic,
 		mp_ioapics[ioapic].mpc_apicid, pin, entry.vector, irq,
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -1084,7 +1084,7 @@ void __init smp_intr_init(void)
         vector = alloc_hipriority_vector();
         per_cpu(vector_irq, cpu)[vector] = irq;
         irq_to_desc(irq)->arch.vector = vector;
-        cpumask_copy(irq_to_desc(irq)->arch.cpu_mask, &cpu_online_map);
+        cpumask_setall(irq_to_desc(irq)->arch.cpu_mask);
     }
 
     /* Direct IPI vectors. */