diff options
author | David Hildenbrand <david@redhat.com> | 2023-07-11 17:34:44 +0200 |
---|---|---|
committer | David Hildenbrand <david@redhat.com> | 2023-07-12 09:27:31 +0200 |
commit | 92a8ee1b594244a82d4c955eab907034f8953f8b (patch) | |
tree | 5ddebb91d74600e3793832ada290e15d3d9a0ac8 /hw | |
parent | aac44204bc6d2a062c2e1658fe6a02a67f55b9e6 (diff) |
virtio-mem: Prepare for device unplug support
In many cases, blindly unplugging a virtio-mem device is problematic. We
can only safely remove a device once:
* The guest is not expecting to be able to read unplugged memory
(unplugged-inaccessible == on)
* The virtio-mem device does not have memory plugged (size == 0)
* The virtio-mem device does not have outstanding requests to the VM to
plug memory (requested-size == 0)
So let's add a callback to the virtio-mem device class to check for that.
We'll wire-up virtio-mem-pci next.
Message-ID: <20230711153445.514112-7-david@redhat.com>
Tested-by: Mario Casquero <mcasquer@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Diffstat (limited to 'hw')
-rw-r--r-- | hw/virtio/virtio-mem.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c index 3f41e00e74..b6e781741e 100644 --- a/hw/virtio/virtio-mem.c +++ b/hw/virtio/virtio-mem.c @@ -1512,6 +1512,30 @@ static void virtio_mem_rdm_unregister_listener(RamDiscardManager *rdm, QLIST_REMOVE(rdl, next); } +static void virtio_mem_unplug_request_check(VirtIOMEM *vmem, Error **errp) +{ + if (vmem->unplugged_inaccessible == ON_OFF_AUTO_OFF) { + /* + * We could allow it with a usable region size of 0, but let's just + * not care about that legacy setting. + */ + error_setg(errp, "virtio-mem device cannot get unplugged while" + " '" VIRTIO_MEM_UNPLUGGED_INACCESSIBLE_PROP "' != 'on'"); + return; + } + + if (vmem->size) { + error_setg(errp, "virtio-mem device cannot get unplugged while" + " '" VIRTIO_MEM_SIZE_PROP "' != '0'"); + return; + } + if (vmem->requested_size) { + error_setg(errp, "virtio-mem device cannot get unplugged while" + " '" VIRTIO_MEM_REQUESTED_SIZE_PROP "' != '0'"); + return; + } +} + static void virtio_mem_class_init(ObjectClass *klass, void *data) { DeviceClass *dc = DEVICE_CLASS(klass); @@ -1534,6 +1558,7 @@ static void virtio_mem_class_init(ObjectClass *klass, void *data) vmc->get_memory_region = virtio_mem_get_memory_region; vmc->add_size_change_notifier = virtio_mem_add_size_change_notifier; vmc->remove_size_change_notifier = virtio_mem_remove_size_change_notifier; + vmc->unplug_request_check = virtio_mem_unplug_request_check; rdmc->get_min_granularity = virtio_mem_rdm_get_min_granularity; rdmc->is_populated = virtio_mem_rdm_is_populated; |