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KVM: s390: use cookies for ioeventfd

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Make use of cookies for the virtio ccw notification hypercall to speed up
lookup of devices on the io bus.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
[Small fix to a comment. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Cornelia Huck 2013-07-03 16:30:54 +02:00 committed by Paolo Bonzini
parent 126a5af520
commit 85dfe87e24
1 changed files with 13 additions and 4 deletions
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17
arch/s390/kvm/diag.c
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@ -119,12 +119,21 @@ static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
* The layout is as follows:
* - gpr 2 contains the subchannel id (passed as addr)
* - gpr 3 contains the virtqueue index (passed as datamatch)
* - gpr 4 contains the index on the bus (optionally)
*/
ret = kvm_io_bus_write(vcpu->kvm, KVM_VIRTIO_CCW_NOTIFY_BUS,
vcpu->run->s.regs.gprs[2],
8, &vcpu->run->s.regs.gprs[3]);
ret = kvm_io_bus_write_cookie(vcpu->kvm, KVM_VIRTIO_CCW_NOTIFY_BUS,
vcpu->run->s.regs.gprs[2],
8, &vcpu->run->s.regs.gprs[3],
vcpu->run->s.regs.gprs[4]);
srcu_read_unlock(&vcpu->kvm->srcu, idx);
/* kvm_io_bus_write returns -EOPNOTSUPP if it found no match. */
/*
* Return cookie in gpr 2, but don't overwrite the register if the
* diagnose will be handled by userspace.
*/
if (ret != -EOPNOTSUPP)
vcpu->run->s.regs.gprs[2] = ret;
/* kvm_io_bus_write_cookie returns -EOPNOTSUPP if it found no match. */
return ret < 0 ? ret : 0;
}