Changelog in v5:
-Fix to automatically enable CONFIG_VIRTIO and CONFIG_VIRTIO_BALLOON with CONFIG_KVM_FREE_PAGE_HINTING
-Moved virtio_ballon hinting_vq code under KVM_FREE_PAGE_HINTING ifdef
-Changes to add VIRTIO_GUEST_PAGE_HINTING_VQ as guest feature which after feature negotiation with QEMU enables guest page hinting support if supported
-Moved sysctl to vm_table struct from fs_table struct
-Fix to disable posioning when guest page hinting is enabled
-QEMU changes
- Removed unencessary comment from page_hinting_request()
- Removed extra variable 'i' from pop_hinting_addr()
- Changes to support VIRTIO_GUEST_PAGE_HINTING_VQ feature negotiation
Virtio interface changes are picked up from Wei's patch-set for Virtio-balloon enhancement[3]. "Wei, How would you like me to credit you in the final patch?")
