update from 4.2 to 4.3,gpu passthrough vm cannot boot

[zuni11]

guest: ubuntu15.10，seabios, nvidia K80 passthrough,working fine @4.2
update to 4.3,the vm cannot find boot disk,boot failed.
pls help me.
the issue like this.

here is my config files:
-----------------------------------------------------------------------------------------------------
root@pve2:~# pveversion -v
proxmox-ve: 4.3-71 (running kernel: 4.4.21-1-pve)
pve-manager: 4.3-10 (running version: 4.3-10/7230e60f)
pve-kernel-4.4.21-1-pve: 4.4.21-71
pve-kernel-4.4.19-1-pve: 4.4.19-66
lvm2: 2.02.116-pve3
corosync-pve: 2.4.0-1
libqb0: 1.0-1
pve-cluster: 4.0-47
qemu-server: 4.0-94
pve-firmware: 1.1-10
libpve-common-perl: 4.0-80
libpve-access-control: 4.0-19
libpve-storage-perl: 4.0-68
pve-libspice-server1: 0.12.8-1
vncterm: 1.2-1
pve-docs: 4.3-14
pve-qemu-kvm: 2.7.0-8
pve-container: 1.0-81
pve-firewall: 2.0-31
pve-ha-manager: 1.0-35
ksm-control-daemon: 1.2-1
glusterfs-client: 3.5.2-2+deb8u2
lxc-pve: 2.0.5-1
lxcfs: 2.0.4-pve2
criu: 1.6.0-1
novnc-pve: 0.5-8
smartmontools: 6.5+svn4324-1~pve80
zfsutils: 0.6.5.8-pve13~bpo80
--------------------------------------------------------------------------------
root@pve2:~# vi /etc/pve/storage.cfg
dir: local
path /var/lib/vz
content vztmpl,iso,backup

lvmthin: local-lvm
vgname pve
thinpool data
content rootdir,images
---------------------------------------------------
root@pve2:~# qm config 109
args: -machine pc,max-ram-below-4g=1G
bootdisk: scsi0
cores: 4
hostpci0: 83:00,pcie=1
ide2: none,media=cdrom
machine: q35
memory: 4096
name: ubuntu1510-k80
net0: virtio=3A:C9:53:50:6E1,bridge=vmbr0
numa: 0
ostype: l26
scsi0: local-lvm:vm-109-disk-1,size=32G
scsihw: virtio-scsi-pci
smbios1: uuid=ef4e3eb4-4234-4b35-816f-d478eee464f8
sockets: 1

 

[zuni11]

update,reinstall ubuntu with ovfm,gpu passthrough is ok.
so i think the issue is 4.3 seabios cannot boot when gpu passthrough.