[vfio-users] vfio fails Guest FreeBSD9.3 host Fedora 23

[Alex Williamson]

On Wed, 1 Jun 2016 15:46:10 -0400
chintu hetam <rometoroam at gmail.com> wrote:

> hugepages doesn't work with VFIO it works with vhost.

TBH I don't have a lot of faith in your setup since you haven't really
shown how you're allocating 1G hugepages, or even 2M, which many people
here are using successfully.  Here's a simple test:

# cd /sys/kernel/mm/hugepages/hugepages-1048576kB/
# cat nr_hugepages

How many do you have available?  If less than 32, then:

# echo 32 > nr_hugepages

Recheck how many are available, you may not be able to get 32 except
via boot options.  If less, adjust the VM memory size accordingly in
the command below.

Mount your 1G hugepages:

# mkdir /hugepages1G
# mount -t hugetlbfs -o pagesize=1G hugetlbfs /hugepages1G

Bind your device to vfio-pci:

# virsh nodedev-detach pci_0000_aa_06_0

Start a simple VM:

# /usr/bin/qemu-kvm -m 32G -mem-path /hugepages1G -nodefaults -monitor
stdio -nographic -device vfio-pci,host=aa:06.0

This will give you a (qemu) prompt where you can type 'quit' or ^C to
kill it.  If this works, then your problem is with configuring your
system to use 1G hugepages or with libvirt.  Please test.  Thanks,

Alex