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-rw-r--r--docs/devel/migration/vfio.rst6
-rw-r--r--hw/core/machine.c1
-rw-r--r--hw/vfio/helpers.c17
-rw-r--r--hw/vfio/migration-multifd.c79
-rw-r--r--hw/vfio/migration-multifd.h3
-rw-r--r--hw/vfio/migration.c10
-rw-r--r--hw/vfio/pci.c10
-rw-r--r--hw/vfio/vfio-helpers.h2
-rw-r--r--hw/vfio/vfio-migration-internal.h1
-rw-r--r--include/hw/vfio/vfio-device.h1
10 files changed, 129 insertions, 1 deletions
diff --git a/docs/devel/migration/vfio.rst b/docs/devel/migration/vfio.rst
index 2d8e5ca9dd..dae3a98830 100644
--- a/docs/devel/migration/vfio.rst
+++ b/docs/devel/migration/vfio.rst
@@ -247,3 +247,9 @@ The multifd VFIO device state transfer is controlled by
 "x-migration-multifd-transfer" VFIO device property. This property defaults to
 AUTO, which means that VFIO device state transfer via multifd channels is
 attempted in configurations that otherwise support it.
+
+Some host platforms (like ARM64) require that VFIO device config is loaded only
+after all iterables were loaded, during non-iterables loading phase.
+Such interlocking is controlled by "x-migration-load-config-after-iter" VFIO
+device property, which in its default setting (AUTO) does so only on platforms
+that actually require it.
diff --git a/hw/core/machine.c b/hw/core/machine.c
index e869821b22..16640b700f 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -39,6 +39,7 @@
 
 GlobalProperty hw_compat_10_0[] = {
     { "scsi-hd", "dpofua", "off" },
+    { "vfio-pci", "x-migration-load-config-after-iter", "off" },
 };
 const size_t hw_compat_10_0_len = G_N_ELEMENTS(hw_compat_10_0);
 
diff --git a/hw/vfio/helpers.c b/hw/vfio/helpers.c
index 9a5f621545..23d13e5db5 100644
--- a/hw/vfio/helpers.c
+++ b/hw/vfio/helpers.c
@@ -209,3 +209,20 @@ retry:
 
     return info;
 }
+
+bool vfio_arch_wants_loading_config_after_iter(void)
+{
+    /*
+     * Starting the config load only after all iterables were loaded (during
+     * non-iterables loading phase) is required for ARM64 due to this platform
+     * VFIO dependency on interrupt controller being loaded first.
+     *
+     * See commit d329f5032e17 ("vfio: Move the saving of the config space to
+     * the right place in VFIO migration").
+     */
+#if defined(TARGET_ARM)
+    return true;
+#else
+    return false;
+#endif
+}
diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c
index 55635486c8..e539befaa9 100644
--- a/hw/vfio/migration-multifd.c
+++ b/hw/vfio/migration-multifd.c
@@ -23,6 +23,7 @@
 #include "migration-multifd.h"
 #include "vfio-migration-internal.h"
 #include "trace.h"
+#include "vfio-helpers.h"
 
 #define VFIO_DEVICE_STATE_CONFIG_STATE (1)
 
@@ -35,6 +36,18 @@ typedef struct VFIODeviceStatePacket {
     uint8_t data[0];
 } QEMU_PACKED VFIODeviceStatePacket;
 
+bool vfio_load_config_after_iter(VFIODevice *vbasedev)
+{
+    if (vbasedev->migration_load_config_after_iter == ON_OFF_AUTO_ON) {
+        return true;
+    } else if (vbasedev->migration_load_config_after_iter == ON_OFF_AUTO_OFF) {
+        return false;
+    }
+
+    assert(vbasedev->migration_load_config_after_iter == ON_OFF_AUTO_AUTO);
+    return vfio_arch_wants_loading_config_after_iter();
+}
+
 /* type safety */
 typedef struct VFIOStateBuffers {
     GArray *array;
@@ -50,6 +63,9 @@ typedef struct VFIOMultifd {
     bool load_bufs_thread_running;
     bool load_bufs_thread_want_exit;
 
+    bool load_bufs_iter_done;
+    QemuCond load_bufs_iter_done_cond;
+
     VFIOStateBuffers load_bufs;
     QemuCond load_bufs_buffer_ready_cond;
     QemuCond load_bufs_thread_finished_cond;
@@ -394,6 +410,22 @@ static bool vfio_load_bufs_thread(void *opaque, bool *should_quit, Error **errp)
         multifd->load_buf_idx++;
     }
 
+    if (vfio_load_config_after_iter(vbasedev)) {
+        while (!multifd->load_bufs_iter_done) {
+            qemu_cond_wait(&multifd->load_bufs_iter_done_cond,
+                           &multifd->load_bufs_mutex);
+
+            /*
+             * Need to re-check cancellation immediately after wait in case
+             * cond was signalled by vfio_load_cleanup_load_bufs_thread().
+             */
+            if (vfio_load_bufs_thread_want_exit(multifd, should_quit)) {
+                error_setg(errp, "operation cancelled");
+                goto thread_exit;
+            }
+        }
+    }
+
     if (!vfio_load_bufs_thread_load_config(vbasedev, errp)) {
         goto thread_exit;
     }
@@ -413,6 +445,48 @@ thread_exit:
     return ret;
 }
 
+int vfio_load_state_config_load_ready(VFIODevice *vbasedev)
+{
+    VFIOMigration *migration = vbasedev->migration;
+    VFIOMultifd *multifd = migration->multifd;
+    int ret = 0;
+
+    if (!vfio_multifd_transfer_enabled(vbasedev)) {
+        error_report("%s: got DEV_CONFIG_LOAD_READY outside multifd transfer",
+                     vbasedev->name);
+        return -EINVAL;
+    }
+
+    if (!vfio_load_config_after_iter(vbasedev)) {
+        error_report("%s: got DEV_CONFIG_LOAD_READY but was disabled",
+                     vbasedev->name);
+        return -EINVAL;
+    }
+
+    assert(multifd);
+
+    /* The lock order is load_bufs_mutex -> BQL so unlock BQL here first */
+    bql_unlock();
+    WITH_QEMU_LOCK_GUARD(&multifd->load_bufs_mutex) {
+        if (multifd->load_bufs_iter_done) {
+            /* Can't print error here as we're outside BQL */
+            ret = -EINVAL;
+            break;
+        }
+
+        multifd->load_bufs_iter_done = true;
+        qemu_cond_signal(&multifd->load_bufs_iter_done_cond);
+    }
+    bql_lock();
+
+    if (ret) {
+        error_report("%s: duplicate DEV_CONFIG_LOAD_READY",
+                     vbasedev->name);
+    }
+
+    return ret;
+}
+
 static VFIOMultifd *vfio_multifd_new(void)
 {
     VFIOMultifd *multifd = g_new(VFIOMultifd, 1);
@@ -425,6 +499,9 @@ static VFIOMultifd *vfio_multifd_new(void)
     multifd->load_buf_idx_last = UINT32_MAX;
     qemu_cond_init(&multifd->load_bufs_buffer_ready_cond);
 
+    multifd->load_bufs_iter_done = false;
+    qemu_cond_init(&multifd->load_bufs_iter_done_cond);
+
     multifd->load_bufs_thread_running = false;
     multifd->load_bufs_thread_want_exit = false;
     qemu_cond_init(&multifd->load_bufs_thread_finished_cond);
@@ -448,6 +525,7 @@ static void vfio_load_cleanup_load_bufs_thread(VFIOMultifd *multifd)
             multifd->load_bufs_thread_want_exit = true;
 
             qemu_cond_signal(&multifd->load_bufs_buffer_ready_cond);
+            qemu_cond_signal(&multifd->load_bufs_iter_done_cond);
             qemu_cond_wait(&multifd->load_bufs_thread_finished_cond,
                            &multifd->load_bufs_mutex);
         }
@@ -460,6 +538,7 @@ static void vfio_multifd_free(VFIOMultifd *multifd)
     vfio_load_cleanup_load_bufs_thread(multifd);
 
     qemu_cond_destroy(&multifd->load_bufs_thread_finished_cond);
+    qemu_cond_destroy(&multifd->load_bufs_iter_done_cond);
     vfio_state_buffers_destroy(&multifd->load_bufs);
     qemu_cond_destroy(&multifd->load_bufs_buffer_ready_cond);
     qemu_mutex_destroy(&multifd->load_bufs_mutex);
diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h
index ebf22a7997..82d2d3a1fd 100644
--- a/hw/vfio/migration-multifd.h
+++ b/hw/vfio/migration-multifd.h
@@ -20,9 +20,12 @@ void vfio_multifd_cleanup(VFIODevice *vbasedev);
 bool vfio_multifd_transfer_supported(void);
 bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev);
 
+bool vfio_load_config_after_iter(VFIODevice *vbasedev);
 bool vfio_multifd_load_state_buffer(void *opaque, char *data, size_t data_size,
                                     Error **errp);
 
+int vfio_load_state_config_load_ready(VFIODevice *vbasedev);
+
 void vfio_multifd_emit_dummy_eos(VFIODevice *vbasedev, QEMUFile *f);
 
 bool
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index c329578eec..4c06e3db93 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -675,7 +675,11 @@ static void vfio_save_state(QEMUFile *f, void *opaque)
     int ret;
 
     if (vfio_multifd_transfer_enabled(vbasedev)) {
-        vfio_multifd_emit_dummy_eos(vbasedev, f);
+        if (vfio_load_config_after_iter(vbasedev)) {
+            qemu_put_be64(f, VFIO_MIG_FLAG_DEV_CONFIG_LOAD_READY);
+        } else {
+            vfio_multifd_emit_dummy_eos(vbasedev, f);
+        }
         return;
     }
 
@@ -784,6 +788,10 @@ static int vfio_load_state(QEMUFile *f, void *opaque, int version_id)
 
             return ret;
         }
+        case VFIO_MIG_FLAG_DEV_CONFIG_LOAD_READY:
+        {
+            return vfio_load_state_config_load_ready(vbasedev);
+        }
         default:
             error_report("%s: Unknown tag 0x%"PRIx64, vbasedev->name, data);
             return -EINVAL;
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 910042c6c2..09acad002a 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3642,6 +3642,9 @@ static const Property vfio_pci_dev_properties[] = {
                 vbasedev.migration_multifd_transfer,
                 vfio_pci_migration_multifd_transfer_prop, OnOffAuto,
                 .set_default = true, .defval.i = ON_OFF_AUTO_AUTO),
+    DEFINE_PROP_ON_OFF_AUTO("x-migration-load-config-after-iter", VFIOPCIDevice,
+                            vbasedev.migration_load_config_after_iter,
+                            ON_OFF_AUTO_AUTO),
     DEFINE_PROP_BOOL("migration-events", VFIOPCIDevice,
                      vbasedev.migration_events, false),
     DEFINE_PROP_BOOL("x-no-mmap", VFIOPCIDevice, vbasedev.no_mmap, false),
@@ -3818,6 +3821,13 @@ static void vfio_pci_dev_class_init(ObjectClass *klass, const void *data)
                                           "x-migration-multifd-transfer",
                                           "Transfer this device state via "
                                           "multifd channels when live migrating it");
+    object_class_property_set_description(klass, /* 10.1 */
+                                          "x-migration-load-config-after-iter",
+                                          "Start the config load only after "
+                                          "all iterables were loaded (during "
+                                          "non-iterables loading phase) when "
+                                          "doing live migration of device state "
+                                          "via multifd channels");
 }
 
 static const TypeInfo vfio_pci_dev_info = {
diff --git a/hw/vfio/vfio-helpers.h b/hw/vfio/vfio-helpers.h
index 54a327ffbc..ce31758080 100644
--- a/hw/vfio/vfio-helpers.h
+++ b/hw/vfio/vfio-helpers.h
@@ -32,4 +32,6 @@ struct vfio_device_info *vfio_get_device_info(int fd);
 int vfio_kvm_device_add_fd(int fd, Error **errp);
 int vfio_kvm_device_del_fd(int fd, Error **errp);
 
+bool vfio_arch_wants_loading_config_after_iter(void);
+
 #endif /* HW_VFIO_VFIO_HELPERS_H */
diff --git a/hw/vfio/vfio-migration-internal.h b/hw/vfio/vfio-migration-internal.h
index a8b456b239..54141e27e6 100644
--- a/hw/vfio/vfio-migration-internal.h
+++ b/hw/vfio/vfio-migration-internal.h
@@ -32,6 +32,7 @@
 #define VFIO_MIG_FLAG_DEV_SETUP_STATE   (0xffffffffef100003ULL)
 #define VFIO_MIG_FLAG_DEV_DATA_STATE    (0xffffffffef100004ULL)
 #define VFIO_MIG_FLAG_DEV_INIT_DATA_SENT (0xffffffffef100005ULL)
+#define VFIO_MIG_FLAG_DEV_CONFIG_LOAD_READY (0xffffffffef100006ULL)
 
 typedef struct VFIODevice VFIODevice;
 typedef struct VFIOMultifd VFIOMultifd;
diff --git a/include/hw/vfio/vfio-device.h b/include/hw/vfio/vfio-device.h
index 1901a35aa9..dac3fdce15 100644
--- a/include/hw/vfio/vfio-device.h
+++ b/include/hw/vfio/vfio-device.h
@@ -67,6 +67,7 @@ typedef struct VFIODevice {
     bool ram_block_discard_allowed;
     OnOffAuto enable_migration;
     OnOffAuto migration_multifd_transfer;
+    OnOffAuto migration_load_config_after_iter;
     bool migration_events;
     bool use_region_fds;
     VFIODeviceOps *ops;