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libvhost-user: Fix some memtable remap cases

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If a new setmemtable command comes in once the vhost threads are
running, it will remap the guests address space and the threads
will now be looking in the wrong place.

Fortunately we're running this command under lock, so we can
update the queue mappings so that threads will look in the new-right
place.

Note: This doesn't fix things that the threads might be doing
without a lock (e.g. a readv/writev!)  That's for another time.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This commit is contained in:
Dr. David Alan Gilbert
2019-08-12 17:35:19 +01:00
parent 1222f01555
commit 49e9ec749d
2 changed files with 28 additions and 8 deletions
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33
contrib/libvhost-user/libvhost-user.c
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@ -564,6 +564,21 @@ vu_reset_device_exec(VuDev *dev, VhostUserMsg *vmsg)
return false;
}
static bool
map_ring(VuDev *dev, VuVirtq *vq)
{
vq->vring.desc = qva_to_va(dev, vq->vra.desc_user_addr);
vq->vring.used = qva_to_va(dev, vq->vra.used_user_addr);
vq->vring.avail = qva_to_va(dev, vq->vra.avail_user_addr);
DPRINT("Setting virtq addresses:\n");
DPRINT(" vring_desc at %p\n", vq->vring.desc);
DPRINT(" vring_used at %p\n", vq->vring.used);
DPRINT(" vring_avail at %p\n", vq->vring.avail);
return !(vq->vring.desc && vq->vring.used && vq->vring.avail);
}
static bool
vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
{
@ -767,6 +782,14 @@ vu_set_mem_table_exec(VuDev *dev, VhostUserMsg *vmsg)
close(vmsg->fds[i]);
}
for (i = 0; i < dev->max_queues; i++) {
if (dev->vq[i].vring.desc) {
if (map_ring(dev, &dev->vq[i])) {
vu_panic(dev, "remaping queue %d during setmemtable", i);
}
}
}
return false;
}
@ -853,18 +876,12 @@ vu_set_vring_addr_exec(VuDev *dev, VhostUserMsg *vmsg)
DPRINT(" avail_user_addr: 0x%016" PRIx64 "\n", vra->avail_user_addr);
DPRINT(" log_guest_addr: 0x%016" PRIx64 "\n", vra->log_guest_addr);
vq->vra = *vra;
vq->vring.flags = vra->flags;
vq->vring.desc = qva_to_va(dev, vra->desc_user_addr);
vq->vring.used = qva_to_va(dev, vra->used_user_addr);
vq->vring.avail = qva_to_va(dev, vra->avail_user_addr);
vq->vring.log_guest_addr = vra->log_guest_addr;
DPRINT("Setting virtq addresses:\n");
DPRINT(" vring_desc at %p\n", vq->vring.desc);
DPRINT(" vring_used at %p\n", vq->vring.used);
DPRINT(" vring_avail at %p\n", vq->vring.avail);
if (!(vq->vring.desc && vq->vring.used && vq->vring.avail)) {
if (map_ring(dev, vq)) {
vu_panic(dev, "Invalid vring_addr message");
return false;
}