On Fri, 3 Mar 2023 20:16:19 +0000 Joao Martins <joao.m.mart...@oracle.com> wrote:
> On 03/03/2023 19:40, Alex Williamson wrote: > > On Fri, 3 Mar 2023 19:14:50 +0000 > > Joao Martins <joao.m.mart...@oracle.com> wrote: > > > >> On 03/03/2023 17:05, Alex Williamson wrote: > >>> On Fri, 3 Mar 2023 16:58:55 +0000 > >>> Joao Martins <joao.m.mart...@oracle.com> wrote: > >>> > >>>> On 03/03/2023 00:19, Joao Martins wrote: > >>>>> On 02/03/2023 18:42, Alex Williamson wrote: > >>>>>> On Thu, 2 Mar 2023 00:07:35 +0000 > >>>>>> Joao Martins <joao.m.mart...@oracle.com> wrote: > >>>>>>> @@ -426,6 +427,11 @@ void > >>>>>>> vfio_unblock_multiple_devices_migration(void) > >>>>>>> multiple_devices_migration_blocker = NULL; > >>>>>>> } > >>>>>>> > >>>>>>> +static bool vfio_have_giommu(VFIOContainer *container) > >>>>>>> +{ > >>>>>>> + return !QLIST_EMPTY(&container->giommu_list); > >>>>>>> +} > >>>>>> > >>>>>> I think it's the case, but can you confirm we build the giommu_list > >>>>>> regardless of whether the vIOMMU is actually enabled? > >>>>>> > >>>>> I think that is only non-empty when we have the first IOVA mappings > >>>>> e.g. on > >>>>> IOMMU passthrough mode *I think* it's empty. Let me confirm. > >>>>> > >>>> Yeap, it's empty. > >>>> > >>>>> Otherwise I'll have to find a TYPE_IOMMU_MEMORY_REGION object to > >>>>> determine if > >>>>> the VM was configured with a vIOMMU or not. That is to create the LM > >>>>> blocker. > >>>>> > >>>> I am trying this way, with something like this, but neither > >>>> x86_iommu_get_default() nor below is really working out yet. A little > >>>> afraid of > >>>> having to add the live migration blocker on each machine_init_done hook, > >>>> unless > >>>> t here's a more obvious way. vfio_realize should be at a much later > >>>> stage, so I > >>>> am surprised how an IOMMU object doesn't exist at that time. > >>> > >>> Can we just test whether the container address space is system_memory? > >> > >> IIUC, it doesn't work (see below snippet). > >> > >> The problem is that you start as a regular VFIO guest, and when the guest > >> boot > >> is when new mappings get established/invalidated and propagated into > >> listeners > >> (vfio_listener_region_add) and they morph into having a giommu. And that's > >> when > >> you can figure out in higher layers that 'you have a vIOMMU' as that's > >> when the > >> address space gets changed? That is without being specific to a particular > >> IOMMU > >> model. Maybe region_add is where to add, but then it then depends on the > >> guest. > > > > This doesn't seem right to me, look for instance at > > pci_device_iommu_address_space() which returns address_space_memory > > when there is no vIOMMU. If devices share an address space, they can > > share a container. When a vIOMMU is present (not even enabled), each > > device gets it's own container due to the fact that it's in its own > > address space (modulo devices within the same address space due to > > aliasing). > > You're obviously right, I was reading this whole thing wrong. This works as > far > as I tested with an iommu=pt guest (and without an vIOMMU). > > I am gonna shape this up, and hopefully submit v3 during over night. > > @@ -416,9 +416,26 @@ void vfio_unblock_multiple_devices_migration(void) > multiple_devices_migration_blocker = NULL; > } > > -static bool vfio_have_giommu(VFIOContainer *container) > +static VFIOAddressSpace *vfio_get_address_space(AddressSpace *as); > + > +int vfio_block_giommu_migration(VFIODevice *vbasedev, Error **errp) > { > - return !QLIST_EMPTY(&container->giommu_list); > + int ret; > + > + if (vbasedev->type == VFIO_DEVICE_TYPE_PCI && > + !vfio_has_iommu(vbasedev)) { > + return 0; > + } > + > + error_setg(&giommu_migration_blocker, > + "Migration is currently not supported with vIOMMU enabled"); > + ret = migrate_add_blocker(giommu_migration_blocker, errp); > + if (ret < 0) { > + error_free(giommu_migration_blocker); > + giommu_migration_blocker = NULL; > + } > + > + return ret; > } > diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c > index 939dcc3d4a9e..f4cf0b41a157 100644 > --- a/hw/vfio/pci.c > +++ b/hw/vfio/pci.c > @@ -2843,6 +2843,15 @@ static void vfio_unregister_req_notifier(VFIOPCIDevice > *vdev) > vdev->req_enabled = false; > } > > +bool vfio_has_iommu(VFIODevice *vbasedev) > +{ > + VFIOPCIDevice *vdev = container_of(vbasedev, VFIOPCIDevice, vbasedev); > + PCIDevice *pdev = &vdev->pdev; > + AddressSpace *as = &address_space_memory; > + > + return !(pci_device_iommu_address_space(pdev) == as); > +} Shouldn't this be something non-PCI specific like: return vbasedev->group->container->space != &address_space_memory; Thanks, Alex