KVM: s390: add clear I/O irq operation for FLIC

Introduce a FLIC operation for clearing I/O interrupts for a subchannel.

Rationale: According to the platform specification, pending I/O
interruption requests have to be revoked in certain situations. For
instance, according to the Principles of Operation (page 17-27), a
subchannel put into the installed parameters initialized state is in the
same state as after an I/O system reset (just parameters possibly changed).
This implies that any I/O interrupts for that subchannel are no longer
pending (as I/O system resets clear I/O interrupts). Therefore, we need an
interface to clear pending I/O interrupts.

Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
This commit is contained in:
Halil Pasic 2016-01-25 19:10:40 +01:00 committed by Cornelia Huck
parent dad7eefbd0
commit 6d28f789bf
3 changed files with 32 additions and 0 deletions

View File

@ -11,6 +11,7 @@ FLIC provides support to
- add interrupts (KVM_DEV_FLIC_ENQUEUE)
- inspect currently pending interrupts (KVM_FLIC_GET_ALL_IRQS)
- purge all pending floating interrupts (KVM_DEV_FLIC_CLEAR_IRQS)
- purge one pending floating I/O interrupt (KVM_DEV_FLIC_CLEAR_IO_IRQ)
- enable/disable for the guest transparent async page faults
- register and modify adapter interrupt sources (KVM_DEV_FLIC_ADAPTER_*)
@ -40,6 +41,11 @@ Groups:
Simply deletes all elements from the list of currently pending floating
interrupts. No interrupts are injected into the guest.
KVM_DEV_FLIC_CLEAR_IO_IRQ
Deletes one (if any) I/O interrupt for a subchannel identified by the
subsystem identification word passed via the buffer specified by
attr->addr (address) and attr->attr (length).
KVM_DEV_FLIC_APF_ENABLE
Enables async page faults for the guest. So in case of a major page fault
the host is allowed to handle this async and continues the guest.

View File

@ -25,6 +25,7 @@
#define KVM_DEV_FLIC_APF_DISABLE_WAIT 5
#define KVM_DEV_FLIC_ADAPTER_REGISTER 6
#define KVM_DEV_FLIC_ADAPTER_MODIFY 7
#define KVM_DEV_FLIC_CLEAR_IO_IRQ 8
/*
* We can have up to 4*64k pending subchannels + 8 adapter interrupts,
* as well as up to ASYNC_PF_PER_VCPU*KVM_MAX_VCPUS pfault done interrupts.

View File

@ -2034,6 +2034,27 @@ static int modify_io_adapter(struct kvm_device *dev,
return ret;
}
static int clear_io_irq(struct kvm *kvm, struct kvm_device_attr *attr)
{
const u64 isc_mask = 0xffUL << 24; /* all iscs set */
u32 schid;
if (attr->flags)
return -EINVAL;
if (attr->attr != sizeof(schid))
return -EINVAL;
if (copy_from_user(&schid, (void __user *) attr->addr, sizeof(schid)))
return -EFAULT;
kfree(kvm_s390_get_io_int(kvm, isc_mask, schid));
/*
* If userspace is conforming to the architecture, we can have at most
* one pending I/O interrupt per subchannel, so this is effectively a
* clear all.
*/
return 0;
}
static int flic_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
{
int r = 0;
@ -2067,6 +2088,9 @@ static int flic_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
case KVM_DEV_FLIC_ADAPTER_MODIFY:
r = modify_io_adapter(dev, attr);
break;
case KVM_DEV_FLIC_CLEAR_IO_IRQ:
r = clear_io_irq(dev->kvm, attr);
break;
default:
r = -EINVAL;
}
@ -2085,6 +2109,7 @@ static int flic_has_attr(struct kvm_device *dev,
case KVM_DEV_FLIC_APF_DISABLE_WAIT:
case KVM_DEV_FLIC_ADAPTER_REGISTER:
case KVM_DEV_FLIC_ADAPTER_MODIFY:
case KVM_DEV_FLIC_CLEAR_IO_IRQ:
return 0;
}
return -ENXIO;