[Qemu-devel] [PATCH v4 0/3] vhost: check if vhost has capacity for hotplugged memory

[Igor Mammedov]

v3->v4:
  * rescan all vhost backends when checking for limit (Michael S. Tsirkin)
  * check that used slots are less than limit of new backend (Michael S. 
Tsirkin)
v2->v3:
  * add refcounting of limit by # vhost devices,
    and make vhost_has_free_slot() return true if no vhost devices
    are present at current moment
  * move limit initialization to vhost_dev_init()
  * fail vhost backend intialization if memslots number is more than its 
supported limit

v1->v2:
  * replace probbing with checking for
    /sys/module/vhost/parameters/max_mem_regions and
    if it's missing has non wrong value return
    hardcoded legacy limit (64 slots).

it's defensive patchset which helps to avoid QEMU crashing
at memory hotplug time by checking that vhost has free capacity
for an additional memory slot.

Igor Mammedov (3):
  vhost: add vhost_has_free_slot() interface
  pc-dimm: add vhost slots limit check before commiting to hotplug
  vhost: fail backend intialization if memslots number is more than its
    supported limit

 hw/mem/pc-dimm.c                  |  7 +++++++
 hw/virtio/vhost-backend.c         | 19 +++++++++++++++++++
 hw/virtio/vhost-user.c            |  6 ++++++
 hw/virtio/vhost.c                 | 27 +++++++++++++++++++++++++++
 include/hw/virtio/vhost-backend.h |  2 ++
 include/hw/virtio/vhost.h         |  2 ++
 stubs/Makefile.objs               |  1 +
 stubs/vhost.c                     |  6 ++++++
 8 files changed, 70 insertions(+)
 create mode 100644 stubs/vhost.c

-- 
1.8.3.1