From 85dfe87e24326c472454cc92313ba8c3b4efe53b Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Wed, 3 Jul 2013 16:30:54 +0200 Subject: [PATCH] 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: Cornelia Huck [Small fix to a comment. - Paolo] Signed-off-by: Paolo Bonzini --- arch/s390/kvm/diag.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c index 3074475..3a74d8a 100644 --- a/arch/s390/kvm/diag.c +++ b/arch/s390/kvm/diag.c @@ -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; } -- 2.7.4