qemu-kvm/kvm-vfio-migration-Reset-bytes_transferred-properly.patch

From a63b4010ba4f491c9144afff363bebcf35ecf496 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= <clg@redhat.com>
Date: Wed, 12 Jul 2023 17:46:57 +0200
Subject: [PATCH 20/37] vfio/migration: Reset bytes_transferred properly
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RH-Author: Cédric Le Goater <clg@redhat.com>
RH-MergeRequest: 179: vfio: live migration support
RH-Bugzilla: 2192818
RH-Acked-by: Eric Auger <eric.auger@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Commit: [18/28] e9a70faeca4fd5aa7ef36502cf76bf0b62f65057 (clegoate/qemu-kvm-c9s)

Bugzilla: https://bugzilla.redhat.com/2192818

commit 808642a2f640
Author: Avihai Horon <avihaih@nvidia.com>
Date:   Wed Jun 28 10:31:11 2023 +0300

    vfio/migration: Reset bytes_transferred properly

    Currently, VFIO bytes_transferred is not reset properly:
    1. bytes_transferred is not reset after a VM snapshot (so a migration
       following a snapshot will report incorrect value).
    2. bytes_transferred is a single counter for all VFIO devices, however
       upon migration failure it is reset multiple times, by each VFIO
       device.

    Fix it by introducing a new function vfio_reset_bytes_transferred() and
    calling it during migration and snapshot start.

    Remove existing bytes_transferred reset in VFIO migration state
    notifier, which is not needed anymore.

    Fixes: 3710586caa5d ("qapi: Add VFIO devices migration stats in Migration stats")
    Signed-off-by: Avihai Horon <avihaih@nvidia.com>
    Reviewed-by: Cédric Le Goater <clg@redhat.com>
    Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
    Signed-off-by: Cédric Le Goater <clg@redhat.com>

Conflicts:
    - migration/migration.c
      migration/savevm.c
      context changes due to commit aff3f6606d14 ("migration: Rename
      ram_counters to mig_stats")

Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 hw/vfio/migration.c           |  6 +++++-
 include/hw/vfio/vfio-common.h |  1 +
 migration/migration.c         |  1 +
 migration/migration.h         |  1 +
 migration/savevm.c            |  1 +
 migration/target.c            | 17 +++++++++++++++--
 6 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index acbf0bb7ab..7cf143926c 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -697,7 +697,6 @@ static void vfio_migration_state_notifier(Notifier *notifier, void *data)
     case MIGRATION_STATUS_CANCELLING:
     case MIGRATION_STATUS_CANCELLED:
     case MIGRATION_STATUS_FAILED:
-        bytes_transferred = 0;
         /*
          * If setting the device in RUNNING state fails, the device should
          * be reset. To do so, use ERROR state as a recover state.
@@ -818,6 +817,11 @@ int64_t vfio_mig_bytes_transferred(void)
     return bytes_transferred;
 }
 
+void vfio_reset_bytes_transferred(void)
+{
+    bytes_transferred = 0;
+}
+
 int vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
 {
     int ret = -ENOTSUP;
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 6d1b8487c3..1d19c6f251 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -229,6 +229,7 @@ int vfio_block_multiple_devices_migration(Error **errp);
 void vfio_unblock_multiple_devices_migration(void);
 int vfio_block_giommu_migration(Error **errp);
 int64_t vfio_mig_bytes_transferred(void);
+void vfio_reset_bytes_transferred(void);
 
 #ifdef CONFIG_LINUX
 int vfio_get_region_info(VFIODevice *vbasedev, int index,
diff --git a/migration/migration.c b/migration/migration.c
index 9bf1caee6c..47ad6c43cb 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1638,6 +1638,7 @@ static bool migrate_prepare(MigrationState *s, bool blk, bool blk_inc,
      */
     memset(&ram_counters, 0, sizeof(ram_counters));
     memset(&compression_counters, 0, sizeof(compression_counters));
+    reset_vfio_bytes_transferred();
 
     return true;
 }
diff --git a/migration/migration.h b/migration/migration.h
index e9679f8029..7ccf460aa2 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -495,6 +495,7 @@ bool migration_rate_limit(void);
 void migration_cancel(const Error *error);
 
 void populate_vfio_info(MigrationInfo *info);
+void reset_vfio_bytes_transferred(void);
 void postcopy_temp_page_reset(PostcopyTmpPage *tmp_page);
 
 #endif
diff --git a/migration/savevm.c b/migration/savevm.c
index aff70e6263..83088fc3f8 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1620,6 +1620,7 @@ static int qemu_savevm_state(QEMUFile *f, Error **errp)
     migrate_init(ms);
     memset(&ram_counters, 0, sizeof(ram_counters));
     memset(&compression_counters, 0, sizeof(compression_counters));
+    reset_vfio_bytes_transferred();
     ms->to_dst_file = f;
 
     qemu_mutex_unlock_iothread();
diff --git a/migration/target.c b/migration/target.c
index 00ca007f97..f39c9a8d88 100644
--- a/migration/target.c
+++ b/migration/target.c
@@ -14,12 +14,25 @@
 #include "hw/vfio/vfio-common.h"
 #endif
 
+#ifdef CONFIG_VFIO
 void populate_vfio_info(MigrationInfo *info)
 {
-#ifdef CONFIG_VFIO
     if (vfio_mig_active()) {
         info->vfio = g_malloc0(sizeof(*info->vfio));
         info->vfio->transferred = vfio_mig_bytes_transferred();
     }
-#endif
 }
+
+void reset_vfio_bytes_transferred(void)
+{
+    vfio_reset_bytes_transferred();
+}
+#else
+void populate_vfio_info(MigrationInfo *info)
+{
+}
+
+void reset_vfio_bytes_transferred(void)
+{
+}
+#endif
-- 
2.39.3