Re: [Qemu-devel] [RFC PATCH V2 09/10] Qemu/VFIO: Add SRIOV VF migration support

[Alex Williamson]

On Tue, 2015-11-24 at 21:35 +0800, Lan Tianyu wrote:
> This patch is to add SRIOV VF migration support.
> Create new device type "vfio-sriov" and add faked PCI migration capability
> to the type device.
> 
> The purpose of the new capability
> 1) sync migration status with VF driver in the VM
> 2) Get mailbox irq vector to notify VF driver during migration.
> 3) Provide a way to control injecting irq or not.
> 
> Qemu will migrate PCI configure space regs and MSIX config for VF.
> Inject mailbox irq at last stage of migration to notify VF about
> migration event and wait VF driver ready for migration. VF driver
> writeS PCI config reg PCI_VF_MIGRATION_VF_STATUS in the new cap table
> to tell Qemu.

What makes this sr-iov specific?  Why wouldn't we simply extend vfio-pci
with a migration=on feature?  Thanks,

Alex