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Commit 85dfe87e authored by Cornelia Huck's avatar Cornelia Huck Committed by Paolo Bonzini
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KVM: s390: use cookies for ioeventfd 



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

Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
[Small fix to a comment. - Paolo]
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 126a5af5

arch/s390/kvm/diag.c

+13 −4
Original line number Diff line number Diff line
@@ -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,

	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]);

				      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;

}