On Wed, 23 Sep 2020 04:54:06 +0530
Kirti Wankhede <kwankh...@nvidia.com> wrote:
> Whether the 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 <kwankh...@nvidia.com>
> Reviewed-by: Neo Jia <c...@nvidia.com>
> Acked-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> ---
> hw/vfio/meson.build | 1 +
> hw/vfio/migration.c | 142
> ++++++++++++++++++++++++++++++++++++++++++
> hw/vfio/trace-events | 5 ++
> include/hw/vfio/vfio-common.h | 9 +++
> 4 files changed, 157 insertions(+)
> create mode 100644 hw/vfio/migration.c
>
> diff --git a/hw/vfio/meson.build b/hw/vfio/meson.build
> index 37efa74018bc..da9af297a0c5 100644
> --- a/hw/vfio/meson.build
> +++ b/hw/vfio/meson.build
> @@ -2,6 +2,7 @@ vfio_ss = ss.source_set()
> vfio_ss.add(files(
> 'common.c',
> 'spapr.c',
> + 'migration.c',
> ))
> vfio_ss.add(when: 'CONFIG_VFIO_PCI', if_true: files(
> 'display.c',
> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> new file mode 100644
> index 000000000000..2f760f1f9c47
> --- /dev/null
> +++ b/hw/vfio/migration.c
> @@ -0,0 +1,142 @@
> +/*
> + * Migration support for VFIO devices
> + *
> + * Copyright NVIDIA, Inc. 2020
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2. See
> + * the COPYING file in the top-level directory.
> + */
> +
> +#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;
Unnecessary initialization.
> + int ret = -EINVAL;
return -EINVAL below, this doesn't need to be initialized, use it for
storing actual return values.
> +
> + obj = vbasedev->ops->vfio_get_object(vbasedev);
> + if (!obj) {
> + return ret;
> + }
vfio_migration_init() tests whether the vbasedev->ops supports
vfio_get_object, then calls this, then calls vfio_get_object itself
(added in a later patch, with a strange inconsistency in failure modes).
Wouldn't it make more sense for vfio_migration_init() to pass the
Object since that function also needs it (eventually) and actually does
the existence test?
> +
> + 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;
> + }
If the caller were to pass obj, this is nothing more than a wrapper for
calling vfio_region_setup(), which suggests to me we might not even
need this as a separate function outside of vfio_migration_init().
> +
> + return 0;
> +
> +err:
> + vfio_migration_region_exit(vbasedev);
> + return ret;
> +}
> +
> +static int vfio_migration_init(VFIODevice *vbasedev,
> + struct vfio_region_info *info)
> +{
> + int ret = -EINVAL;
> +
> + if (!vbasedev->ops->vfio_get_object) {
> + return 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;
> +}
> +
> +/* ---------------------------------------------------------------------- */
> +
> +int vfio_migration_probe(VFIODevice *vbasedev, Error **errp)
> +{
> + struct vfio_region_info *info = NULL;
Not sure this initialization is strictly necessary either, but it also
seems to be a common convention for this function, so either way.
Connie, does vfio_ccw_get_region() leak this? It appears to call
vfio_get_dev_region_info() and vfio_get_region_info() several times with
the same pointer without freeing it between uses.
Thanks,
Alex
> + 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;
> + }
> +
> + g_free(info);
> + trace_vfio_migration_probe(vbasedev->name, info->index);
> + return 0;
> +
> +add_blocker:
> + error_setg(&vbasedev->migration_blocker,
> + "VFIO device doesn't support migration");
> + g_free(info);
> +
> + ret = migrate_add_blocker(vbasedev->migration_blocker, &local_err);
> + if (local_err) {
> + error_propagate(errp, local_err);
> + error_free(vbasedev->migration_blocker);
> + vbasedev->migration_blocker = NULL;
> + }
> + return ret;
> +}
> +
> +void vfio_migration_finalize(VFIODevice *vbasedev)
> +{
> + if (vbasedev->migration_blocker) {
> + migrate_del_blocker(vbasedev->migration_blocker);
> + error_free(vbasedev->migration_blocker);
> + vbasedev->migration_blocker = NULL;
> + }
> +
> + vfio_migration_region_exit(vbasedev);
> + g_free(vbasedev->migration);
> +}
> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
> index a0c7b49a2ebc..8fe913175d85 100644
> --- a/hw/vfio/trace-events
> +++ b/hw/vfio/trace-events
> @@ -145,3 +145,8 @@ 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(const 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 ba6169cd926e..8275c4c68f45 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 */
