On 2021/3/3 12:21 上午, David Hildenbrand wrote:
Similar to VFIO, vDPA will go ahead an map+pin all guest memory.
Memory
that used to be discarded will get re-populated and if we
discard+re-access memory after mapping+pinning, the pages mapped
into the
vDPA IOMMU will go out of sync with the actual pages mapped into the
user
space page tables.
Set discarding of RAM broken such that:
- virtio-mem and vhost-vdpa run mutually exclusive
- virtio-balloon is inhibited and no memory discards will get issued
In the future, we might be able to support coordinated discarding of
RAM
as used by virtio-mem and as planned for VFIO.
Cc: Jason Wang <jasowang@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Cindy Lu <lulu@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
Note: I was not actually able to reproduce/test as I fail to get the
vdpa_sim/vdpa_sim_net running on upstream Linux (whetever vdpa,
vhost_vdpa,
vdpa_sim, vdpa_sim_net modules I probe, and in which order, no vdpa
devices
appear under /sys/bus/vdpa/devices/ or /dev/).
The device creation was switched to use vdpa tool that is integrated
with iproue2[1].
[1]
https://git.kernel.org/pub/scm/network/iproute2/iproute2-next.git/commit/?id=143610383da51e1f868c6d5a2a5e2fb552293d18