On 15/07/17 07:17, Alex Williamson wrote: > On Tue, 11 Jul 2017 15:32:18 +1000 > Alexey Kardashevskiy <a...@ozlabs.ru> wrote: > >> At the moment VFIO PCI device initialization works as follows: >> vfio_realize >> vfio_get_group >> vfio_connect_container >> register memory listeners (1) >> update QEMU groups lists >> vfio_kvm_device_add_group >> >> Then (example for pseries) the machine reset hook triggers region_add() >> for all regions where listeners from (1) are listening: >> >> ppc_spapr_reset >> spapr_phb_reset >> spapr_tce_table_enable >> memory_region_add_subregion >> vfio_listener_region_add >> vfio_spapr_create_window >> >> This scheme works fine until we need to handle VFIO PCI device hotplug >> and we want to enable PPC64/sPAPR in-kernel TCE acceleration on, >> i.e. after PCI hotplug we need a place to call >> ioctl(vfio_kvm_device_fd, KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE). >> Since the ioctl needs a LIOBN fd (from sPAPRTCETable) and a IOMMU group fd >> (from VFIOGroup), vfio_listener_region_add() seems to be the only place >> for this ioctl(). >> >> However this only works during boot time because the machine reset >> happens strictly after all devices are finalized. When hotplug happens, >> vfio_listener_region_add() is called when a memory listener is registered >> but when this happens: >> 1. new group is not added to the container->group_list yet; >> 2. VFIO KVM device is unaware of the new IOMMU group. >> >> This moves bits around to have all necessary VFIO infrastructure >> in place for both initial startup and hotplug cases. > > > Wow, for a fairly straight forward patch this changelog is brutal. Can > this be summarized as "Register vfio groups with kvm prior to memory > listener registration such that kvm-vfio pseudo device ioctls are > available during the region_add callback"? If so I'll queue this up > for a pull request prior to soft freeze. Thanks,
It just could have looked like an unnecessary change, hence this changelog. Since it is straight forward, I am ok with your shorter version as well. Thanks. > > Alex > > >> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> >> Reviewed-by: David Gibson <da...@gibson.dropbear.id.au> >> --- >> >> >> This is an independend part of a bigger patchset to enable in-kernel >> acceleration of TCE operations. While I stuck with IOMMU MR QOM-fication, >> let's try to parallel patchset pieces' review/acceptance. >> >> --- >> Changes: >> v3: >> * rebased on current upstream >> >> v2: >> * moved container->initialized back to its correct location >> * added missing QLIST_REMOVE() >> --- >> hw/vfio/common.c | 19 +++++++++++-------- >> 1 file changed, 11 insertions(+), 8 deletions(-) >> >> diff --git a/hw/vfio/common.c b/hw/vfio/common.c >> index 2965b68e5d..4e75dc8c56 100644 >> --- a/hw/vfio/common.c >> +++ b/hw/vfio/common.c >> @@ -1107,6 +1107,14 @@ static int vfio_connect_container(VFIOGroup *group, >> AddressSpace *as, >> goto free_container_exit; >> } >> >> + vfio_kvm_device_add_group(group); >> + >> + QLIST_INIT(&container->group_list); >> + QLIST_INSERT_HEAD(&space->containers, container, next); >> + >> + group->container = container; >> + QLIST_INSERT_HEAD(&container->group_list, group, container_next); >> + >> container->listener = vfio_memory_listener; >> >> memory_listener_register(&container->listener, container->space->as); >> @@ -1120,14 +1128,11 @@ static int vfio_connect_container(VFIOGroup *group, >> AddressSpace *as, >> >> container->initialized = true; >> >> - QLIST_INIT(&container->group_list); >> - QLIST_INSERT_HEAD(&space->containers, container, next); >> - >> - group->container = container; >> - QLIST_INSERT_HEAD(&container->group_list, group, container_next); >> - >> return 0; >> listener_release_exit: >> + QLIST_REMOVE(group, container_next); >> + QLIST_REMOVE(container, next); >> + vfio_kvm_device_del_group(group); >> vfio_listener_release(container); >> >> free_container_exit: >> @@ -1232,8 +1237,6 @@ VFIOGroup *vfio_get_group(int groupid, AddressSpace >> *as, Error **errp) >> >> QLIST_INSERT_HEAD(&vfio_group_list, group, next); >> >> - vfio_kvm_device_add_group(group); >> - >> return group; >> >> close_fd_exit: > -- Alexey
