"prealloc=on" for the memory backend does not work as expected, as
virtio-mem will simply discard all preallocated memory immediately again.
In the best case, it's an expensive NOP. In the worst case, it's an
unexpected allocation error.
Instead, "prealloc=on" should be specified for the virtio-mem device only,
such that virtio-mem will try preallocating memory before plugging
memory dynamically to the guest.
Signed-off-by: David Hildenbrand <da...@redhat.com>
---
hw/virtio/virtio-mem.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c
index 04c223b0c9..6c337db0a7 100644
--- a/hw/virtio/virtio-mem.c
+++ b/hw/virtio/virtio-mem.c
@@ -765,6 +765,13 @@ static void virtio_mem_device_realize(DeviceState *dev,
Error **errp)
return;
}
+ if (vmem->memdev->prealloc) {
+ warn_report("'%s' property specifies a memdev with preallocation"
+ " enabled: %s. Instead, specify 'prealloc=on' for the"
+ " virtio-mem device. ", VIRTIO_MEM_MEMDEV_PROP,
+ object_get_canonical_path_component(OBJECT(vmem->memdev)));
+ }
+
if ((nb_numa_nodes && vmem->node >= nb_numa_nodes) ||
(!nb_numa_nodes && vmem->node)) {
error_setg(errp, "'%s' property has value '%" PRIu32 "', which exceeds"
--
2.34.1
