I have recreated and am attaching console log. This is from ubuntu-precise-12.04-amd64-server-20131003 (ami-b93264d0). This ami boots without the sr-iov attribute which allows me to make changes prior to adding the 'simple' sriov attribute and recreating the problem you are seeing. Removal of the xen_emul_unplug kernel cmdline option and addition of the xen-platform-pci kernel module to the initramfs does not provide relief, therefore I do not believe tha this is related to bug #1268012.
Eugene, thank you for the bug report.
I have recreated and am attaching console log. This is from ubuntu- precise- 12.04-amd64- server- 20131003 (ami-b93264d0). This ami boots without the sr-iov attribute which allows me to make changes prior to adding the 'simple' sriov attribute and recreating the problem you are seeing. Removal of the xen_emul_unplug kernel cmdline option and addition of the xen-platform-pci kernel module to the initramfs does not provide relief, therefore I do not believe tha this is related to bug #1268012.