Commit ffcbbe72 authored by Peter Xu's avatar Peter Xu Committed by Michael S. Tsirkin
Browse files

vhost: add trace for IOTLB miss 



Add some trace points for IOTLB translation for vhost. After vhost-user
is setup, the only IO path that QEMU will participate should be the
IOMMU translation, so it'll be good we can track this with explicit
timestamps when needed to see how long time we take to do the
translation, and whether there's anything stuck inside.  It might be
useful for triaging vhost-user problems.

Signed-off-by: default avatarPeter Xu <peterx@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent b7b12644

hw/virtio/trace-events

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ vhost_region_add_section(const char *name, uint64_t gpa, uint64_t size, uint64_t 
vhost_region_add_section_merge(const char *name, uint64_t new_size, uint64_t gpa, uint64_t owr) "%s: size: 0x%"PRIx64 " gpa: 0x%"PRIx64 " owr: 0x%"PRIx64

vhost_region_add_section_aligned(const char *name, uint64_t gpa, uint64_t size, uint64_t host) "%s: 0x%"PRIx64"+0x%"PRIx64" @ 0x%"PRIx64

vhost_section(const char *name, int r) "%s:%d"

vhost_iotlb_miss(void *dev, int step) "%p step %d"



# hw/virtio/vhost-user.c

vhost_user_postcopy_end_entry(void) ""

hw/virtio/vhost.c

+7 −0
Original line number Diff line number Diff line
@@ -894,12 +894,15 @@ int vhost_device_iotlb_miss(struct vhost_dev *dev, uint64_t iova, int write) 


    rcu_read_lock();



    trace_vhost_iotlb_miss(dev, 1);



    iotlb = address_space_get_iotlb_entry(dev->vdev->dma_as,

                                          iova, write);

    if (iotlb.target_as != NULL) {

        ret = vhost_memory_region_lookup(dev, iotlb.translated_addr,

                                         &uaddr, &len);

        if (ret) {

            trace_vhost_iotlb_miss(dev, 3);

            error_report("Fail to lookup the translated address "

                         "%"PRIx64, iotlb.translated_addr);

            goto out;
@@ -911,10 +914,14 @@ int vhost_device_iotlb_miss(struct vhost_dev *dev, uint64_t iova, int write) 
        ret = vhost_backend_update_device_iotlb(dev, iova, uaddr,

                                                len, iotlb.perm);

        if (ret) {

            trace_vhost_iotlb_miss(dev, 4);

            error_report("Fail to update device iotlb");

            goto out;

        }

    }



    trace_vhost_iotlb_miss(dev, 2);



out:

    rcu_read_unlock();