From 8cb3d83b959be0631cd719b995c40c3cda21cd47 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Thu, 24 Feb 2022 16:20:19 +0200 Subject: vfio: Extend the device migration protocol with RUNNING_P2P The RUNNING_P2P state is designed to support multiple devices in the same VM that are doing P2P transactions between themselves. When in RUNNING_P2P the device must be able to accept incoming P2P transactions but should not generate outgoing P2P transactions. As an optional extension to the mandatory states it is defined as in between STOP and RUNNING: STOP -> RUNNING_P2P -> RUNNING -> RUNNING_P2P -> STOP For drivers that are unable to support RUNNING_P2P the core code silently merges RUNNING_P2P and RUNNING together. Unless driver support is present, the new state cannot be used in SET_STATE. Drivers that support this will be required to implement 4 FSM arcs beyond the basic FSM. 2 of the basic FSM arcs become combination transitions. Compared to the v1 clarification, NDMA is redefined into FSM states and is described in terms of the desired P2P quiescent behavior, noting that halting all DMA is an acceptable implementation. Link: https://lore.kernel.org/all/20220224142024.147653-11-yishaih@nvidia.com Signed-off-by: Jason Gunthorpe Tested-by: Shameer Kolothum Reviewed-by: Kevin Tian Reviewed-by: Alex Williamson Signed-off-by: Yishai Hadas Signed-off-by: Leon Romanovsky --- include/linux/vfio.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/vfio.h b/include/linux/vfio.h index c44e80bbbd3b..66dda06ec42d 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -33,6 +33,7 @@ struct vfio_device { struct vfio_group *group; struct vfio_device_set *dev_set; struct list_head dev_set_list; + unsigned int migration_flags; /* Members below here are private, not for driver use */ refcount_t refcount; -- cgit v1.2.3