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[PULL 05/12] vfio/migration: Block multiple devices migration
From: |
Alex Williamson |
Subject: |
[PULL 05/12] vfio/migration: Block multiple devices migration |
Date: |
Thu, 16 Feb 2023 16:02:17 -0700 |
User-agent: |
StGit/1.5.dev2+g9ce680a52bd9 |
From: Avihai Horon <avihaih@nvidia.com>
Currently VFIO migration doesn't implement some kind of intermediate
quiescent state in which P2P DMAs are quiesced before stopping or
running the device. This can cause problems in multi-device migration
where the devices are doing P2P DMAs, since the devices are not stopped
together at the same time.
Until such support is added, block migration of multiple devices.
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Link: 20230216143630.25610-6-avihaih@nvidia.com">https://lore.kernel.org/r/20230216143630.25610-6-avihaih@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
hw/vfio/common.c | 53 +++++++++++++++++++++++++++++++++++++++++
hw/vfio/migration.c | 6 +++++
include/hw/vfio/vfio-common.h | 2 ++
3 files changed, 61 insertions(+)
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 3a35f4afad64..fe80ccf91419 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -41,6 +41,7 @@
#include "qapi/error.h"
#include "migration/migration.h"
#include "migration/misc.h"
+#include "migration/blocker.h"
#include "sysemu/tpm.h"
VFIOGroupList vfio_group_list =
@@ -337,6 +338,58 @@ bool vfio_mig_active(void)
return true;
}
+static Error *multiple_devices_migration_blocker;
+
+static unsigned int vfio_migratable_device_num(void)
+{
+ VFIOGroup *group;
+ VFIODevice *vbasedev;
+ unsigned int device_num = 0;
+
+ QLIST_FOREACH(group, &vfio_group_list, next) {
+ QLIST_FOREACH(vbasedev, &group->device_list, next) {
+ if (vbasedev->migration) {
+ device_num++;
+ }
+ }
+ }
+
+ return device_num;
+}
+
+int vfio_block_multiple_devices_migration(Error **errp)
+{
+ int ret;
+
+ if (multiple_devices_migration_blocker ||
+ vfio_migratable_device_num() <= 1) {
+ return 0;
+ }
+
+ error_setg(&multiple_devices_migration_blocker,
+ "Migration is currently not supported with multiple "
+ "VFIO devices");
+ ret = migrate_add_blocker(multiple_devices_migration_blocker, errp);
+ if (ret < 0) {
+ error_free(multiple_devices_migration_blocker);
+ multiple_devices_migration_blocker = NULL;
+ }
+
+ return ret;
+}
+
+void vfio_unblock_multiple_devices_migration(void)
+{
+ if (!multiple_devices_migration_blocker ||
+ vfio_migratable_device_num() > 1) {
+ return;
+ }
+
+ migrate_del_blocker(multiple_devices_migration_blocker);
+ error_free(multiple_devices_migration_blocker);
+ multiple_devices_migration_blocker = NULL;
+}
+
static bool vfio_devices_all_dirty_tracking(VFIOContainer *container)
{
VFIOGroup *group;
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index e56eef1ee83c..8e9699966962 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -878,6 +878,11 @@ int vfio_migration_probe(VFIODevice *vbasedev, Error
**errp)
goto add_blocker;
}
+ ret = vfio_block_multiple_devices_migration(errp);
+ if (ret) {
+ return ret;
+ }
+
trace_vfio_migration_probe(vbasedev->name, info->index);
g_free(info);
return 0;
@@ -904,6 +909,7 @@ void vfio_migration_finalize(VFIODevice *vbasedev)
qemu_del_vm_change_state_handler(migration->vm_state);
unregister_savevm(VMSTATE_IF(vbasedev->dev), "vfio", vbasedev);
vfio_migration_exit(vbasedev);
+ vfio_unblock_multiple_devices_migration();
}
if (vbasedev->migration_blocker) {
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index e573f5a9f19f..56b168382469 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -218,6 +218,8 @@ typedef QLIST_HEAD(VFIOGroupList, VFIOGroup) VFIOGroupList;
extern VFIOGroupList vfio_group_list;
bool vfio_mig_active(void);
+int vfio_block_multiple_devices_migration(Error **errp);
+void vfio_unblock_multiple_devices_migration(void);
int64_t vfio_mig_bytes_transferred(void);
#ifdef CONFIG_LINUX
- [PULL 00/12] VFIO updates 2023-02-16, Alex Williamson, 2023/02/16
- [PULL 01/12] linux-headers: Update to v6.2-rc8, Alex Williamson, 2023/02/16
- [PULL 02/12] vfio/migration: Fix NULL pointer dereference bug, Alex Williamson, 2023/02/16
- [PULL 03/12] vfio/migration: Allow migration without VFIO IOMMU dirty tracking support, Alex Williamson, 2023/02/16
- [PULL 04/12] vfio/common: Change vfio_devices_all_running_and_saving() logic to equivalent one, Alex Williamson, 2023/02/16
- [PULL 05/12] vfio/migration: Block multiple devices migration,
Alex Williamson <=
- [PULL 06/12] vfio/migration: Move migration v1 logic to vfio_migration_init(), Alex Williamson, 2023/02/16
- [PULL 07/12] vfio/migration: Rename functions/structs related to v1 protocol, Alex Williamson, 2023/02/16
- [PULL 08/12] vfio/migration: Implement VFIO migration protocol v2, Alex Williamson, 2023/02/16
- [PULL 09/12] vfio/migration: Remove VFIO migration protocol v1, Alex Williamson, 2023/02/16
- [PULL 10/12] vfio: Alphabetize migration section of VFIO trace-events file, Alex Williamson, 2023/02/16
- [PULL 11/12] docs/devel: Align VFIO migration docs to v2 protocol, Alex Williamson, 2023/02/16
- [PULL 12/12] MAINTAINERS: Add myself as VFIO reviewer, Alex Williamson, 2023/02/16
- Re: [PULL 00/12] VFIO updates 2023-02-16, Peter Maydell, 2023/02/21