Re: [PATCH v16 QEMU 05/16] vfio: Add migration region initialization and finalize function

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Kirti Wankhede (kwankhede@nvidia.com) wrote:
> 
> 
> On 3/26/2020 11:22 PM, Dr. David Alan Gilbert wrote:
> > * Kirti Wankhede (kwankhede@nvidia.com) wrote:
> > > - Migration functions are implemented for VFIO_DEVICE_TYPE_PCI device in this
> > >    patch series.
> > > - VFIO device supports migration or not is decided based of migration region
> > >    query. If migration region query is successful and migration region
> > >    initialization is successful then migration is supported else migration is
> > >    blocked.
> > > 
> > > Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
> > > Reviewed-by: Neo Jia <cjia@nvidia.com>
> > > ---
> > >   hw/vfio/Makefile.objs         |   2 +-
> > >   hw/vfio/migration.c           | 138 ++++++++++++++++++++++++++++++++++++++++++
> > >   hw/vfio/trace-events          |   3 +
> > >   include/hw/vfio/vfio-common.h |   9 +++
> > >   4 files changed, 151 insertions(+), 1 deletion(-)
> > >   create mode 100644 hw/vfio/migration.c
> > > 
> > > diff --git a/hw/vfio/Makefile.objs b/hw/vfio/Makefile.objs
> > > index 9bb1c09e8477..8b296c889ed9 100644
> > > --- a/hw/vfio/Makefile.objs
> > > +++ b/hw/vfio/Makefile.objs
> > > @@ -1,4 +1,4 @@
> > > -obj-y += common.o spapr.o
> > > +obj-y += common.o spapr.o migration.o
> > >   obj-$(CONFIG_VFIO_PCI) += pci.o pci-quirks.o display.o
> > >   obj-$(CONFIG_VFIO_CCW) += ccw.o
> > >   obj-$(CONFIG_VFIO_PLATFORM) += platform.o
> > > diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> > > new file mode 100644
> > > index 000000000000..a078dcf1dd8f
> > > --- /dev/null
> > > +++ b/hw/vfio/migration.c
> > > @@ -0,0 +1,138 @@
> > > +/*
> > > + * Migration support for VFIO devices
> > > + *
> > > + * Copyright NVIDIA, Inc. 2019
> > 
> > Time flies by...
> > 
> > > + *
> > > + * This work is licensed under the terms of the GNU GPL, version 2. See
> > > + * the COPYING file in the top-level directory.
> > 
> > Are you sure you want this to be V2 only? Most code added to qemu now is
> > v2 or later.
> > 
> 
> I kept it same as in files vfio-pci and hw/vfio/common.c
> 
> Should it be different? Can you give some reference what it should be?

It's OK to be v2; there's a statement in LICENSE saying hw/vfio is
acceptable for that; most other new code we try and make
'version 2 or later' - if you want it as 2 that is fine though.

Dave

> Thanks,
> Kirti
> 
> > > + */
> > > +
> > > +#include "qemu/osdep.h"
> > > +#include <linux/vfio.h>
> > > +
> > > +#include "hw/vfio/vfio-common.h"
> > > +#include "cpu.h"
> > > +#include "migration/migration.h"
> > > +#include "migration/qemu-file.h"
> > > +#include "migration/register.h"
> > > +#include "migration/blocker.h"
> > > +#include "migration/misc.h"
> > > +#include "qapi/error.h"
> > > +#include "exec/ramlist.h"
> > > +#include "exec/ram_addr.h"
> > > +#include "pci.h"
> > > +#include "trace.h"
> > > +
> > > +static void vfio_migration_region_exit(VFIODevice *vbasedev)
> > > +{
> > > +    VFIOMigration *migration = vbasedev->migration;
> > > +
> > > +    if (!migration) {
> > > +        return;
> > > +    }
> > > +
> > > +    if (migration->region.size) {
> > > +        vfio_region_exit(&migration->region);
> > > +        vfio_region_finalize(&migration->region);
> > > +    }
> > > +}
> > > +
> > > +static int vfio_migration_region_init(VFIODevice *vbasedev, int index)
> > > +{
> > > +    VFIOMigration *migration = vbasedev->migration;
> > > +    Object *obj = NULL;
> > > +    int ret = -EINVAL;
> > > +
> > > +    if (!vbasedev->ops->vfio_get_object) {
> > > +        return ret;
> > > +    }
> > > +
> > > +    obj = vbasedev->ops->vfio_get_object(vbasedev);
> > > +    if (!obj) {
> > > +        return ret;
> > > +    }
> > > +
> > > +    ret = vfio_region_setup(obj, vbasedev, &migration->region, index,
> > > +                            "migration");
> > > +    if (ret) {
> > > +        error_report("%s: Failed to setup VFIO migration region %d: %s",
> > > +                     vbasedev->name, index, strerror(-ret));
> > > +        goto err;
> > > +    }
> > > +
> > > +    if (!migration->region.size) {
> > > +        ret = -EINVAL;
> > > +        error_report("%s: Invalid region size of VFIO migration region %d: %s",
> > > +                     vbasedev->name, index, strerror(-ret));
> > > +        goto err;
> > > +    }
> > > +
> > > +    return 0;
> > > +
> > > +err:
> > > +    vfio_migration_region_exit(vbasedev);
> > > +    return ret;
> > > +}
> > > +
> > > +static int vfio_migration_init(VFIODevice *vbasedev,
> > > +                               struct vfio_region_info *info)
> > > +{
> > > +    int ret;
> > > +
> > > +    vbasedev->migration = g_new0(VFIOMigration, 1);
> > > +
> > > +    ret = vfio_migration_region_init(vbasedev, info->index);
> > > +    if (ret) {
> > > +        error_report("%s: Failed to initialise migration region",
> > > +                     vbasedev->name);
> > > +        g_free(vbasedev->migration);
> > > +        vbasedev->migration = NULL;
> > > +        return ret;
> > > +    }
> > > +
> > > +    return 0;
> > > +}
> > > +
> > > +/* ---------------------------------------------------------------------- */
> > > +
> > > +int vfio_migration_probe(VFIODevice *vbasedev, Error **errp)
> > > +{
> > > +    struct vfio_region_info *info;
> > > +    Error *local_err = NULL;
> > > +    int ret;
> > > +
> > > +    ret = vfio_get_dev_region_info(vbasedev, VFIO_REGION_TYPE_MIGRATION,
> > > +                                   VFIO_REGION_SUBTYPE_MIGRATION, &info);
> > > +    if (ret) {
> > > +        goto add_blocker;
> > > +    }
> > > +
> > > +    ret = vfio_migration_init(vbasedev, info);
> > > +    if (ret) {
> > > +        goto add_blocker;
> > > +    }
> > > +
> > > +    trace_vfio_migration_probe(vbasedev->name, info->index);
> > > +    return 0;
> > > +
> > > +add_blocker:
> > > +    error_setg(&vbasedev->migration_blocker,
> > > +               "VFIO device doesn't support migration");
> > > +    ret = migrate_add_blocker(vbasedev->migration_blocker, &local_err);
> > > +    if (local_err) {
> > > +        error_propagate(errp, local_err);
> > > +        error_free(vbasedev->migration_blocker);
> > > +    }
> > > +    return ret;
> > > +}
> > > +
> > > +void vfio_migration_finalize(VFIODevice *vbasedev)
> > > +{
> > > +    if (vbasedev->migration_blocker) {
> > > +        migrate_del_blocker(vbasedev->migration_blocker);
> > > +        error_free(vbasedev->migration_blocker);
> > > +    }
> > > +
> > > +    vfio_migration_region_exit(vbasedev);
> > > +    g_free(vbasedev->migration);
> > > +}
> > > diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
> > > index 8cdc27946cb8..191a726a1312 100644
> > > --- a/hw/vfio/trace-events
> > > +++ b/hw/vfio/trace-events
> > > @@ -143,3 +143,6 @@ vfio_display_edid_link_up(void) ""
> > >   vfio_display_edid_link_down(void) ""
> > >   vfio_display_edid_update(uint32_t prefx, uint32_t prefy) "%ux%u"
> > >   vfio_display_edid_write_error(void) ""
> > > +
> > > +# migration.c
> > > +vfio_migration_probe(char *name, uint32_t index) " (%s) Region %d"
> > > diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> > > index d69a7f3ae31e..d4b268641173 100644
> > > --- a/include/hw/vfio/vfio-common.h
> > > +++ b/include/hw/vfio/vfio-common.h
> > > @@ -57,6 +57,10 @@ typedef struct VFIORegion {
> > >       uint8_t nr; /* cache the region number for debug */
> > >   } VFIORegion;
> > > +typedef struct VFIOMigration {
> > > +    VFIORegion region;
> > > +} VFIOMigration;
> > > +
> > >   typedef struct VFIOAddressSpace {
> > >       AddressSpace *as;
> > >       QLIST_HEAD(, VFIOContainer) containers;
> > > @@ -113,6 +117,8 @@ typedef struct VFIODevice {
> > >       unsigned int num_irqs;
> > >       unsigned int num_regions;
> > >       unsigned int flags;
> > > +    VFIOMigration *migration;
> > > +    Error *migration_blocker;
> > >   } VFIODevice;
> > >   struct VFIODeviceOps {
> > > @@ -204,4 +210,7 @@ int vfio_spapr_create_window(VFIOContainer *container,
> > >   int vfio_spapr_remove_window(VFIOContainer *container,
> > >                                hwaddr offset_within_address_space);
> > > +int vfio_migration_probe(VFIODevice *vbasedev, Error **errp);
> > > +void vfio_migration_finalize(VFIODevice *vbasedev);
> > > +
> > >   #endif /* HW_VFIO_VFIO_COMMON_H */
> > > -- 
> > > 2.7.0
> > > 
> > --
> > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> > 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK