fix problem with multiple irqs on the same rdt.  need to route to the same
mach and vector number, so just stash that information in the rdt tracking
structure

Reference: /n/atom/patch/applied/multipleirqrdt
Date: Tue Jan  7 04:11:03 CET 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/nix/k10/ioapic.c	Tue Jan  7 04:10:27 2014
+++ /sys/src/nix/k10/ioapic.c	Tue Jan  7 04:10:27 2014
@@ -23,6 +23,9 @@
 	int	intin;
 	u32int	lo;
 
+	u64int	vec;				/* remember vector and mach */
+	int	affinity;
+
 	int	ref;				/* could map to multiple busses */
 	int	enabled;				/* times enabled */
 };
@@ -549,19 +552,25 @@
 	lock(rdt->apic);
 	ainc(&rdt->enabled);
 	lo = (rdt->lo & ~Im);
-	ioapicphysdd(v, &hi, &lo);
 
 	if((rdt->lo & 0xff) == 0){
+		ioapicphysdd(v, &hi, &lo);
 		rdt->lo |= lo & 0xff;
+		rdt->vec = (u64int)hi<<32 | lo;
+		rdt->affinity = v->affinity;
 		rdtvecno[lo&0xff] = rdt;
-	}else
-		DBG("%T: mutiple irq bus %d dev %d\n", v->tbdf, busno, devno);
-
-	rtblput(rdt->apic, rdt->intin, hi, lo);
+		rtblput(rdt->apic, rdt->intin, hi, lo);
+	}else{
+		DBG("%T: mutiple irq bus %d dev %d %s\n", v->tbdf, busno, devno, v->name);
+		hi = rdt->vec>>32;
+		lo = rdt->vec;
+		v->affinity = rdt->affinity;
+		v->vno = lo & 0xff;
+	}
 	unlock(rdt->apic);
 
-	DBG("busno %d devno %d hi %#.8ux lo %#.8ux vecno %d\n",
-		busno, devno, hi, lo, v->vno);
+	DBG("busno %d devno %d hi %#.8ux lo %#.8ux vno %d af %d\n",
+		busno, devno, hi, lo, v->vno, v->affinity);
 	v->eoi = lapiceoi;
 	v->type = "ioapic";