[dpdk-dev] [PATCH v2 5/7] net/virtio_user: add vhost kernel support
jianfeng.tan at intel.com
Wed Jan 4 08:22:08 CET 2017
Sorry, I forget to reply this comment.
On 12/26/2016 3:44 PM, Yuanhan Liu wrote:
>> + /* Does not work when VIRTIO_F_IOMMU_PLATFORM now, why? */
> Because this feature need the vhost IOTLB support from the device
> emulation. Patches for QEMU hasn't been merged yet, but it has been
> there for a while.
Yes. And it's in need of help from QEMU.
> Since we don't have the support yet, for sure it won't work. But
> I'm wondering why you have to disable it explicitly?
Here we do not have QEMU. Frontend driver talks with vhost-net through
virtio_user_dev. And both ends claim to support VIRTIO_F_IOMMU_PLATFORM.
So this feature bit will be negotiated if we don't explicitly disable
it. In my previous test, it fails in vhost_init_device_iotlb() of vhost
kernel module. My guess is that, for this feature, without the help of
QEMU, vhost kernel module cannot work independently.
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