lkml.org 
[lkml]   [2019]   [Aug]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH V4 4/9] vhost: reset invalidate_count in vhost_set_vring_num_addr()
    Date
    The vhost_set_vring_num_addr() could be called in the middle of
    invalidate_range_start() and invalidate_range_end(). If we don't reset
    invalidate_count after the un-registering of MMU notifier, the
    invalidate_cont will run out of sync (e.g never reach zero). This will
    in fact disable the fast accessor path. Fixing by reset the count to
    zero.

    Reported-by: Michael S. Tsirkin <mst@redhat.com>
    Reported-by: Jason Gunthorpe <jgg@mellanox.com>
    Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address")
    Signed-off-by: Jason Wang <jasowang@redhat.com>
    ---
    drivers/vhost/vhost.c | 4 ++++
    1 file changed, 4 insertions(+)

    diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
    index 2a3154976277..2a7217c33668 100644
    --- a/drivers/vhost/vhost.c
    +++ b/drivers/vhost/vhost.c
    @@ -2073,6 +2073,10 @@ static long vhost_vring_set_num_addr(struct vhost_dev *d,
    d->has_notifier = false;
    }

    + /* reset invalidate_count in case we are in the middle of
    + * invalidate_start() and invalidate_end().
    + */
    + vq->invalidate_count = 0;
    vhost_uninit_vq_maps(vq);
    #endif

    --
    2.18.1
    \
     
     \ /
      Last update: 2019-08-07 09:08    [W:3.610 / U:0.080 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site