On 11/24/2015 05:38 AM, Lan Tianyu wrote:

This patchset is to propose a solution of adding live migration
support for SRIOV NIC.

During migration, Qemu needs to let VF driver in the VM to know
migration start and end. Qemu adds faked PCI migration capability
to help to sync status between two sides during migration.

Qemu triggers VF's mailbox irq via sending MSIX msg when migration
status is changed. VF driver tells Qemu its mailbox vector index
via the new PCI capability. In some cases(NIC is suspended or closed),
VF mailbox irq is freed and VF driver can disable irq injecting via
new capability.

VF driver will put down nic before migration and put up again on
the target machine.

Lan Tianyu (3):
   VFIO: Add new ioctl cmd VFIO_GET_PCI_CAP_INFO
   PCI: Add macros for faked PCI migration capability
   Ixgbevf: Add migration support for ixgbevf driver

  drivers/net/ethernet/intel/ixgbevf/ixgbevf.h      |   5 ++
  drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c | 102 ++++++++++++++++++++++
  drivers/vfio/pci/vfio_pci.c                       |  21 +++++
  drivers/vfio/pci/vfio_pci_config.c                |  38 ++++++--
  drivers/vfio/pci/vfio_pci_private.h               |   5 ++
  include/uapi/linux/pci_regs.h                     |  18 +++-
  include/uapi/linux/vfio.h                         |  12 +++
  7 files changed, 194 insertions(+), 7 deletions(-)

I'm still not a fan of this approach.  I really feel like this is 
something that should be resolved by extending the existing PCI hot-plug 
rather than trying to instrument this per driver.  Then you will get the 
goodness for multiple drivers and multiple OSes instead of just one.  An 
added advantage to dealing with this in the PCI hot-plug environment 
would be that you could then still do a hot-plug even if the guest 
didn't load a driver for the VF since you would be working with the PCI 
slot instead of the device itself.

- Alex