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Re: [PATCH v5 13/15] vfio/migration: Block migration with vIOMMU
From: |
Alex Williamson |
Subject: |
Re: [PATCH v5 13/15] vfio/migration: Block migration with vIOMMU |
Date: |
Tue, 7 Mar 2023 09:42:45 -0700 |
On Tue, 7 Mar 2023 09:38:51 -0700
Alex Williamson <alex.williamson@redhat.com> wrote:
> On Tue, 7 Mar 2023 12:54:48 +0000
> Joao Martins <joao.m.martins@oracle.com> wrote:
>
> > Migrating with vIOMMU will require either tracking maximum
> > IOMMU supported address space (e.g. 39/48 address width on Intel)
> > or range-track current mappings and dirty track the new ones
> > post starting dirty tracking. This will be done as a separate
> > series, so add a live migration blocker until that is fixed.
> >
> > Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> > Reviewed-by: Cédric Le Goater <clg@redhat.com>
> > ---
> > hw/vfio/common.c | 46 +++++++++++++++++++++++++++++++++++
> > hw/vfio/migration.c | 5 ++++
> > hw/vfio/pci.c | 1 +
> > include/hw/vfio/vfio-common.h | 2 ++
> > 4 files changed, 54 insertions(+)
> >
> > diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> > index 2639b393a781..2b9bcf70aa36 100644
> > --- a/hw/vfio/common.c
> > +++ b/hw/vfio/common.c
> > @@ -362,6 +362,7 @@ bool vfio_mig_active(void)
> > }
> >
> > static Error *multiple_devices_migration_blocker;
> > +static Error *giommu_migration_blocker;
> >
> > static unsigned int vfio_migratable_device_num(void)
> > {
> > @@ -413,6 +414,51 @@ void vfio_unblock_multiple_devices_migration(void)
> > multiple_devices_migration_blocker = NULL;
> > }
> >
> > +static bool vfio_viommu_preset(void)
> > +{
> > + VFIOAddressSpace *space;
> > +
> > + QLIST_FOREACH(space, &vfio_address_spaces, list) {
> > + if (space->as != &address_space_memory) {
> > + return true;
> > + }
> > + }
> > +
> > + return false;
> > +}
> > +
> > +int vfio_block_giommu_migration(Error **errp)
> > +{
> > + int ret;
> > +
> > + if (giommu_migration_blocker ||
> > + !vfio_viommu_preset()) {
> > + 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;
> > +}
> > +
> > +void vfio_unblock_giommu_migration(void)
> > +{
> > + if (!giommu_migration_blocker ||
> > + vfio_viommu_preset()) {
> > + return;
> > + }
> > +
> > + migrate_del_blocker(giommu_migration_blocker);
> > + error_free(giommu_migration_blocker);
> > + giommu_migration_blocker = NULL;
> > +}
> > +
> > static void vfio_set_migration_error(int err)
> > {
> > MigrationState *ms = migrate_get_current();
> > diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> > index a2c3d9bade7f..776fd2d7cdf3 100644
> > --- a/hw/vfio/migration.c
> > +++ b/hw/vfio/migration.c
> > @@ -634,6 +634,11 @@ int vfio_migration_probe(VFIODevice *vbasedev, Error
> > **errp)
> > return ret;
> > }
> >
> > + ret = vfio_block_giommu_migration(errp);
> > + if (ret) {
> > + return ret;
> > + }
> > +
> > trace_vfio_migration_probe(vbasedev->name);
> > return 0;
> >
> > diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> > index 939dcc3d4a9e..30a271eab38c 100644
> > --- a/hw/vfio/pci.c
> > +++ b/hw/vfio/pci.c
> > @@ -3185,6 +3185,7 @@ static void vfio_instance_finalize(Object *obj)
> > */
> > vfio_put_device(vdev);
> > vfio_put_group(group);
> > + vfio_unblock_giommu_migration();
> > }
>
> Hmm, doesn't this mean we're adding the viommu migration blocker in
> common code but only removing it in pci code? Granted that only PCI
> devices currently have IOMMUs, but ick. Thanks,
Or maybe the justification is that vfio_migration_probe() is also only
called by the vfio-pci vfio_realize(), so it's more symmetric than it
appears. Ok. Thanks,
Alex
- [PATCH v5 09/15] vfio/common: Record DMA mapped IOVA ranges, (continued)
- [PATCH v5 09/15] vfio/common: Record DMA mapped IOVA ranges, Joao Martins, 2023/03/07
- [PATCH v5 10/15] vfio/common: Add device dirty page tracking start/stop, Joao Martins, 2023/03/07
- [PATCH v5 11/15] vfio/common: Extract code from vfio_get_dirty_bitmap() to new function, Joao Martins, 2023/03/07
- [PATCH v5 12/15] vfio/common: Add device dirty page bitmap sync, Joao Martins, 2023/03/07
- [PATCH v5 13/15] vfio/migration: Block migration with vIOMMU, Joao Martins, 2023/03/07
- [PATCH v5 14/15] vfio/migration: Query device dirty page tracking support, Joao Martins, 2023/03/07
- [PATCH v5 15/15] docs/devel: Document VFIO device dirty page tracking, Joao Martins, 2023/03/07