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authorMichael S. Tsirkin <mst@redhat.com>2013-02-28 12:33:16 +0100
committerMarcelo Tosatti <mtosatti@redhat.com>2013-03-05 19:12:09 -0300
commit07e169335ff0570c6e67b5ccf74d793f00ab0834 (patch)
treef96290e4e141305498fe5cb97a9efffc958c0d7a /drivers/s390/kvm
parent503cd0c50ac7161eb5c3891b48b620cb0a5521cd (diff)
downloadop-kernel-dev-07e169335ff0570c6e67b5ccf74d793f00ab0834.zip
op-kernel-dev-07e169335ff0570c6e67b5ccf74d793f00ab0834.tar.gz
virtio_ccw: pass a cookie value to kvm hypercall
Lookups by channel/vq pair on host during virtio notifications might be expensive. Interpret hypercall return value as a cookie which host can use to do device lookups for the next notification more efficiently. [CH: Fix line > 80 chars] Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'drivers/s390/kvm')
-rw-r--r--drivers/s390/kvm/virtio_ccw.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index 2029b6c..3d65752 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -77,6 +77,7 @@ struct virtio_ccw_vq_info {
void *queue;
struct vq_info_block *info_block;
struct list_head node;
+ long cookie;
};
#define KVM_VIRTIO_CCW_RING_ALIGN 4096
@@ -145,15 +146,18 @@ static int ccw_io_helper(struct virtio_ccw_device *vcdev,
}
static inline long do_kvm_notify(struct subchannel_id schid,
- unsigned long queue_index)
+ unsigned long queue_index,
+ long cookie)
{
register unsigned long __nr asm("1") = KVM_S390_VIRTIO_CCW_NOTIFY;
register struct subchannel_id __schid asm("2") = schid;
register unsigned long __index asm("3") = queue_index;
register long __rc asm("2");
+ register long __cookie asm("4") = cookie;
asm volatile ("diag 2,4,0x500\n"
- : "=d" (__rc) : "d" (__nr), "d" (__schid), "d" (__index)
+ : "=d" (__rc) : "d" (__nr), "d" (__schid), "d" (__index),
+ "d"(__cookie)
: "memory", "cc");
return __rc;
}
@@ -166,7 +170,8 @@ static void virtio_ccw_kvm_notify(struct virtqueue *vq)
vcdev = to_vc_device(info->vq->vdev);
ccw_device_get_schid(vcdev->cdev, &schid);
- do_kvm_notify(schid, virtqueue_get_queue_index(vq));
+ info->cookie = do_kvm_notify(schid, virtqueue_get_queue_index(vq),
+ info->cookie);
}
static int virtio_ccw_read_vq_conf(struct virtio_ccw_device *vcdev,
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