On 06/13/2017 11:59 AM, Jason Wang wrote:
On 2017年06月13日 11:55, Jason Wang wrote:
The issue is what if there's a mismatch of max #sgs between qemu and
vhost?
When the vhost backend is used, QEMU is not involved in the data
path. The vhost backend
directly gets what is offered by the guest from the vq.
FYI, qemu will try to fallback to userspace if there's something wrong
with vhost-kernel (e.g the IOMMU support). This doesn't work for
vhost-user actually, but it works for vhost-kernel.
Thanks
That wouldn't be a problem. When it falls back to the QEMU backend,
the "max_chain_size" will be set according to the QEMU backend
(e.g. 1023). Guest will read the max_chain_size register.