virtio-ccw: virtio-ccw adapter interrupt support.

Implement the new CCW_CMD_SET_IND_ADAPTER command and try to enable
adapter interrupts for every device on the first startup. If the host
does not support adapter interrupts, fall back to normal I/O interrupts.

virtio-ccw adapter interrupts use the same isc as normal I/O subchannels
and share a summary indicator for all devices sharing the same indicator
area.

Indicator bits for the individual virtqueues may be contained in the same
indicator area for different devices.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

arch/s390/include/asm/irq.h

@@ -53,6 +53,7 @@ enum interruption_class {
 	IRQIO_PCI,
 	IRQIO_MSI,
 	IRQIO_VIR,
+	IRQIO_VAI,
 	NMI_NMI,
 	CPU_RST,
 	NR_ARCH_IRQS

arch/s390/kernel/irq.c

@@ -84,6 +84,7 @@ static const struct irq_class irqclass_sub_desc[NR_ARCH_IRQS] = {
 	[IRQIO_PCI]  = {.name = "PCI", .desc = "[I/O] PCI Interrupt" },
 	[IRQIO_MSI]  = {.name = "MSI", .desc = "[I/O] MSI Interrupt" },
 	[IRQIO_VIR]  = {.name = "VIR", .desc = "[I/O] Virtual I/O Devices"},
+	[IRQIO_VAI]  = {.name = "VAI", .desc = "[I/O] Virtual I/O Devices AI"},
 	[NMI_NMI]    = {.name = "NMI", .desc = "[NMI] Machine Check"},
 	[CPU_RST]    = {.name = "RST", .desc = "[CPU] CPU Restart"},
 };