> -----Original Message-----
> From: Adrian Moreno [mailto:amore...@redhat.com]
> Sent: Friday, October 25, 2019 8:21 PM
> To: Liu, Yong <yong....@intel.com>; maxime.coque...@redhat.com; Bie, Tiwei
> <tiwei....@intel.com>; Wang, Zhihong <zhihong.w...@intel.com>
> Cc: dev@dpdk.org
> Subject: Re: [PATCH] vhost: fix vhost user virtqueue not accessable
>
> Hi Marvin,
>
> On 10/25/19 6:20 PM, Marvin Liu wrote:
> > Log feature is disabled in vhost user, so that log address was invalid
> > when checking. Add feature bit check can skip useless address check.
> >
> Just so I understand, what conditions is the log address invalid?
>
> > Fixes: 04cfc7fdbfca ("vhost: translate incoming log address to gpa")
> >
> > Signed-off-by: Marvin Liu <yong....@intel.com>
> > ---
> > lib/librte_vhost/vhost_user.c | 16 +++++++++-------
> > 1 file changed, 9 insertions(+), 7 deletions(-)
> >
> > diff --git a/lib/librte_vhost/vhost_user.c
> b/lib/librte_vhost/vhost_user.c
> > index 61ef699ac..0407fdc29 100644
> > --- a/lib/librte_vhost/vhost_user.c
> > +++ b/lib/librte_vhost/vhost_user.c
> > @@ -741,13 +741,15 @@ translate_ring_addresses(struct virtio_net *dev,
> int vq_index)
> > vq->last_avail_idx = vq->used->idx;
> > }
> >
> > - vq->log_guest_addr =
> > - translate_log_addr(dev, vq, addr->log_guest_addr);
> > - if (vq->log_guest_addr == 0) {
> > - RTE_LOG(DEBUG, VHOST_CONFIG,
> > - "(%d) failed to map log_guest_addr .\n",
> > - dev->vid);
> > - return dev;
> > + if (dev->features & (1ULL << VHOST_F_LOG_ALL)) {
> > + vq->log_guest_addr =
> > + translate_log_addr(dev, vq, addr->log_guest_addr);
>
> VHOST_F_LOG_ALL is only negotiated once the migration has started (at least
> from
> qemu's perspective).
> That means that we will postponing the translation of the log address to
> the
> vhost_user_set_vring_addr() call that follows the VHOST_F_LOG_ALL enabling.
> In
> that call there are (at least) two things that could go wrong and lead to a
> migration failure:
> - If VHOST_USER_F_PROTOCOL_FEATURES is not enabled, the address won't be
> translated:
>
> vhost_user:795
> if ((vq->enabled && (dev->features &
> (1ULL << VHOST_USER_F_PROTOCOL_FEATURES))) ||
> access_ok) {
> dev = translate_ring_addresses(dev, msg->payload.addr.index);
> if (!dev)
> return RTE_VHOST_MSG_RESULT_ERR;
>
> *pdev = dev;
> }
>
> - If the IOMMU is enabled and there's a miss, we would have to wait for the
> IOTLB_UPDATE and during that time, there would be failed accesses to the
> (still
> untranslated) log address.
>
>
Thanks, Adrian.
Log address can be zero when logging is not enabled.
How about add other criteria after translation? Log address will be translated
anyway and not affect vq status.
vq->log_guest_addr =
translate_log_addr(dev, vq, addr->log_guest_addr);
- if (vq->log_guest_addr == 0) {
+ if (vq->log_guest_addr == 0 && addr->flags) {
RTE_LOG(DEBUG, VHOST_CONFIG,
"(%d) failed to map log_guest_addr .\n",
dev->vid);
return dev;
}
Meanwhile, log address of packed ring is fixed to zero. Is any special reason
to do that?
Regards,
Marvin
>
> > + if (vq->log_guest_addr == 0) {
> > + RTE_LOG(DEBUG, VHOST_CONFIG,
> > + "(%d) failed to map log_guest_addr .\n",
> > + dev->vid);
> > + return dev;
> > + }
> > }
> > vq->access_ok = 1;
> >
> >
> Thanks,
> Adrian
