qemu-kvm/kvm-vfio-migration-Change-vIOMMU-blocker-from-global-to-.patch

From 35c7d0d3b02d61d6f29afae74bd83edd70a6a1b4 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 26/37] vfio/migration: Change vIOMMU blocker from global to
 per device
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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: [24/28] 8fda1c82a81fadd4f38e6a5e878c9228a81c0f6e (clegoate/qemu-kvm-c9s)

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

commit 3c26c80a0a26
Author: Zhenzhong Duan <zhenzhong.duan@intel.com>
Date:   Mon Jul 3 15:15:07 2023 +0800

    vfio/migration: Change vIOMMU blocker from global to per device

    Contrary to multiple device blocker which needs to consider already-attached
    devices to unblock/block dynamically, the vIOMMU migration blocker is a device
    specific config. Meaning it only needs to know whether the device is bypassing
    or not the vIOMMU (via machine property, or per pxb-pcie::bypass_iommu), and
    does not need the state of currently present devices. For this reason, the
    vIOMMU global migration blocker can be consolidated into the per-device
    migration blocker, allowing us to remove some unnecessary code.

    This change also makes vfio_mig_active() more accurate as it doesn't check for
    global blocker.

    Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
    Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
    Reviewed-by: Cédric Le Goater <clg@redhat.com>
    Signed-off-by: Cédric Le Goater <clg@redhat.com>

Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 hw/vfio/common.c              | 51 ++---------------------------------
 hw/vfio/migration.c           |  7 ++---
 hw/vfio/pci.c                 |  1 -
 include/hw/vfio/vfio-common.h |  3 +--
 4 files changed, 7 insertions(+), 55 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 136d8243d6..e815f6ba30 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -362,7 +362,6 @@ bool vfio_mig_active(void)
 }
 
 static Error *multiple_devices_migration_blocker;
-static Error *giommu_migration_blocker;
 
 static unsigned int vfio_migratable_device_num(void)
 {
@@ -420,55 +419,9 @@ void vfio_unblock_multiple_devices_migration(void)
     multiple_devices_migration_blocker = NULL;
 }
 
-static bool vfio_viommu_preset(void)
+bool vfio_viommu_preset(VFIODevice *vbasedev)
 {
-    VFIOAddressSpace *space;
-
-    QLIST_FOREACH(space, &vfio_address_spaces, list) {
-        if (space->as != &address_space_memory) {
-            return true;
-        }
-    }
-
-    return false;
-}
-
-int vfio_block_giommu_migration(VFIODevice *vbasedev, Error **errp)
-{
-    int ret;
-
-    if (giommu_migration_blocker ||
-        !vfio_viommu_preset()) {
-        return 0;
-    }
-
-    if (vbasedev->enable_migration == ON_OFF_AUTO_ON) {
-        error_setg(errp,
-                   "Migration is currently not supported with vIOMMU enabled");
-        return -EINVAL;
-    }
-
-    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_migration_finalize(void)
-{
-    if (!giommu_migration_blocker ||
-        vfio_viommu_preset()) {
-        return;
-    }
-
-    migrate_del_blocker(giommu_migration_blocker);
-    error_free(giommu_migration_blocker);
-    giommu_migration_blocker = NULL;
+    return vbasedev->group->container->space->as != &address_space_memory;
 }
 
 static void vfio_set_migration_error(int err)
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 1db7d52ab2..e6e5e85f75 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -878,9 +878,10 @@ int vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
         return ret;
     }
 
-    ret = vfio_block_giommu_migration(vbasedev, errp);
-    if (ret) {
-        return ret;
+    if (vfio_viommu_preset(vbasedev)) {
+        error_setg(&err, "%s: Migration is currently not supported "
+                   "with vIOMMU enabled", vbasedev->name);
+        return vfio_block_migration(vbasedev, err, errp);
     }
 
     trace_vfio_migration_realize(vbasedev->name);
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 2d059832a4..922c81872c 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3279,7 +3279,6 @@ static void vfio_instance_finalize(Object *obj)
      */
     vfio_put_device(vdev);
     vfio_put_group(group);
-    vfio_migration_finalize();
 }
 
 static void vfio_exitfn(PCIDevice *pdev)
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 93429b9abb..45167c8a8a 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -227,7 +227,7 @@ extern VFIOGroupList vfio_group_list;
 bool vfio_mig_active(void);
 int vfio_block_multiple_devices_migration(VFIODevice *vbasedev, Error **errp);
 void vfio_unblock_multiple_devices_migration(void);
-int vfio_block_giommu_migration(VFIODevice *vbasedev, Error **errp);
+bool vfio_viommu_preset(VFIODevice *vbasedev);
 int64_t vfio_mig_bytes_transferred(void);
 void vfio_reset_bytes_transferred(void);
 
@@ -254,6 +254,5 @@ int vfio_spapr_remove_window(VFIOContainer *container,
 
 int vfio_migration_realize(VFIODevice *vbasedev, Error **errp);
 void vfio_migration_exit(VFIODevice *vbasedev);
-void vfio_migration_finalize(void);
 
 #endif /* HW_VFIO_VFIO_COMMON_H */
-- 
2.39.3