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KVM: S390: Add virtio hotplug add support 

The one big missing feature in s390-virtio was hotplugging. This is no more.
This patch implements hotplug add support, so you can on the fly add new devices
in the guest.

Keep in mind that this needs a patch for qemu to actually leverage the
functionality.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Alexander Graf 2010-08-24 15:48:51 +02:00 committed by Avi Kivity
parent fc678d67fe
commit cefa33e2f8
2 changed files with 48 additions and 0 deletions
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1
arch/s390/include/asm/kvm_virtio.h
View File

@ -59,5 +59,6 @@ struct kvm_vqconfig {
#define VIRTIO_PARAM_MASK 0xff
#define VIRTIO_PARAM_VRING_INTERRUPT 0x0
#define VIRTIO_PARAM_CONFIG_CHANGED 0x1
#define VIRTIO_PARAM_DEV_ADD 0x2
#endif

47
drivers/s390/kvm/kvm_virtio.c
View File

@ -32,6 +32,7 @@
* The pointer to our (page) of device descriptions.
*/
static void *kvm_devices;
struct work_struct hotplug_work;
struct kvm_device {
struct virtio_device vdev;
@ -327,6 +328,47 @@ static void scan_devices(void)
}
}
/*
* match for a kvm device with a specific desc pointer
*/
static int match_desc(struct device *dev, void *data)
{
if ((ulong)to_kvmdev(dev_to_virtio(dev))->desc == (ulong)data)
return 1;
return 0;
}
/*
* hotplug_device tries to find changes in the device page.
*/
static void hotplug_devices(struct work_struct *dummy)
{
unsigned int i;
struct kvm_device_desc *d;
struct device *dev;
for (i = 0; i < PAGE_SIZE; i += desc_size(d)) {
d = kvm_devices + i;
/* end of list */
if (d->type == 0)
break;
/* device already exists */
dev = device_find_child(kvm_root, d, match_desc);
if (dev) {
/* XXX check for hotplug remove */
put_device(dev);
continue;
}
/* new device */
printk(KERN_INFO "Adding new virtio device %p\n", d);
add_kvm_device(d, i);
}
}
/*
* we emulate the request_irq behaviour on top of s390 extints
*/
@ -357,6 +399,9 @@ static void kvm_extint_handler(u16 code)
break;
}
case VIRTIO_PARAM_DEV_ADD:
schedule_work(&hotplug_work);
break;
case VIRTIO_PARAM_VRING_INTERRUPT:
default:
vring_interrupt(0, vq);
@ -390,6 +435,8 @@ static int __init kvm_devices_init(void)
kvm_devices = (void *) real_memory_size;
INIT_WORK(&hotplug_work, hotplug_devices);
ctl_set_bit(0, 9);
register_external_interrupt(0x2603, kvm_extint_handler);