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qemu/vfio-Register-SaveVMHandlers-for-VFIO-device.patch
imxcc 4daf6a89f5 Add migration support for VFIO devices 
Add migration support for VFIO devices and the pre-requisite for this

Signed-off-by: imxcc <xingchaochao@huawei.com>
2021-07-29 11:36:27 +08:00

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From cd5b58f2ba20e59f2c29d955b8bbd7f5016030b7 Mon Sep 17 00:00:00 2001
From: Kirti Wankhede <kwankhede@nvidia.com>
Date: Mon, 26 Oct 2020 15:06:17 +0530
Subject: [PATCH] vfio: Register SaveVMHandlers for VFIO device
Define flags to be used as delimiter in migration stream for VFIO devices.
Added .save_setup and .save_cleanup functions. Map & unmap migration
region from these functions at source during saving or pre-copy phase.
Set VFIO device state depending on VM's state. During live migration, VM is
running when .save_setup is called, _SAVING | _RUNNING state is set for VFIO
device. During save-restore, VM is paused, _SAVING state is set for VFIO device.
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
hw/vfio/migration.c | 102 +++++++++++++++++++++++++++++++++++++++++++
hw/vfio/trace-events | 2 +
2 files changed, 104 insertions(+)
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 0c6c9b655f..405228fc5a 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -8,12 +8,15 @@
*/
#include "qemu/osdep.h"
+#include "qemu/main-loop.h"
+#include "qemu/cutils.h"
#include <linux/vfio.h>
#include "sysemu/sysemu.h"
#include "hw/vfio/vfio-common.h"
#include "cpu.h"
#include "migration/migration.h"
+#include "migration/vmstate.h"
#include "migration/qemu-file.h"
#include "migration/register.h"
#include "migration/blocker.h"
@@ -25,6 +28,22 @@
#include "trace.h"
#include "hw/hw.h"
+/*
+ * Flags to be used as unique delimiters for VFIO devices in the migration
+ * stream. These flags are composed as:
+ * 0xffffffff => MSB 32-bit all 1s
+ * 0xef10 => Magic ID, represents emulated (virtual) function IO
+ * 0x0000 => 16-bits reserved for flags
+ *
+ * The beginning of state information is marked by _DEV_CONFIG_STATE,
+ * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a
+ * certain state information is marked by _END_OF_STATE.
+ */
+#define VFIO_MIG_FLAG_END_OF_STATE (0xffffffffef100001ULL)
+#define VFIO_MIG_FLAG_DEV_CONFIG_STATE (0xffffffffef100002ULL)
+#define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xffffffffef100003ULL)
+#define VFIO_MIG_FLAG_DEV_DATA_STATE (0xffffffffef100004ULL)
+
static inline int vfio_mig_access(VFIODevice *vbasedev, void *val, int count,
off_t off, bool iswrite)
{
@@ -129,6 +148,75 @@ static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t mask,
return 0;
}
+static void vfio_migration_cleanup(VFIODevice *vbasedev)
+{
+ VFIOMigration *migration = vbasedev->migration;
+
+ if (migration->region.mmaps) {
+ vfio_region_unmap(&migration->region);
+ }
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int vfio_save_setup(QEMUFile *f, void *opaque)
+{
+ VFIODevice *vbasedev = opaque;
+ VFIOMigration *migration = vbasedev->migration;
+ int ret;
+
+ trace_vfio_save_setup(vbasedev->name);
+
+ qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
+
+ if (migration->region.mmaps) {
+ /*
+ * Calling vfio_region_mmap() from migration thread. Memory API called
+ * from this function require locking the iothread when called from
+ * outside the main loop thread.
+ */
+ qemu_mutex_lock_iothread();
+ ret = vfio_region_mmap(&migration->region);
+ qemu_mutex_unlock_iothread();
+ if (ret) {
+ error_report("%s: Failed to mmap VFIO migration region: %s",
+ vbasedev->name, strerror(-ret));
+ error_report("%s: Falling back to slow path", vbasedev->name);
+ }
+ }
+
+ ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_MASK,
+ VFIO_DEVICE_STATE_SAVING);
+ if (ret) {
+ error_report("%s: Failed to set state SAVING", vbasedev->name);
+ return ret;
+ }
+
+ qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
+
+ ret = qemu_file_get_error(f);
+ if (ret) {
+ return ret;
+ }
+
+ return 0;
+}
+
+static void vfio_save_cleanup(void *opaque)
+{
+ VFIODevice *vbasedev = opaque;
+
+ vfio_migration_cleanup(vbasedev);
+ trace_vfio_save_cleanup(vbasedev->name);
+}
+
+static SaveVMHandlers savevm_vfio_handlers = {
+ .save_setup = vfio_save_setup,
+ .save_cleanup = vfio_save_cleanup,
+};
+
+/* ---------------------------------------------------------------------- */
+
static void vfio_vmstate_change(void *opaque, int running, RunState state)
{
VFIODevice *vbasedev = opaque;
@@ -215,6 +303,8 @@ static int vfio_migration_init(VFIODevice *vbasedev,
int ret;
Object *obj;
VFIOMigration *migration;
+ char id[256] = "";
+ g_autofree char *path = NULL, *oid = NULL;
if (!vbasedev->ops->vfio_get_object) {
return -EINVAL;
@@ -244,6 +334,18 @@ static int vfio_migration_init(VFIODevice *vbasedev,
migration = vbasedev->migration;
migration->vbasedev = vbasedev;
+
+ oid = vmstate_if_get_id(VMSTATE_IF(DEVICE(obj)));
+ if (oid) {
+ path = g_strdup_printf("%s/vfio", oid);
+ } else {
+ path = g_strdup("vfio");
+ }
+ strpadcpy(id, sizeof(id), path, '\0');
+
+ register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1, &savevm_vfio_handlers,
+ vbasedev);
+
migration->vm_state = qemu_add_vm_change_state_handler(vfio_vmstate_change,
vbasedev);
migration->migration_state.notify = vfio_migration_state_notifier;
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index bd3d47b005..86c18def01 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -149,3 +149,5 @@ vfio_migration_probe(const char *name, uint32_t index) " (%s) Region %d"
vfio_migration_set_state(const char *name, uint32_t state) " (%s) state %d"
vfio_vmstate_change(const char *name, int running, const char *reason, uint32_t dev_state) " (%s) running %d reason %s device state %d"
vfio_migration_state_notifier(const char *name, const char *state) " (%s) state %s"
+vfio_save_setup(const char *name) " (%s)"
+vfio_save_cleanup(const char *name) " (%s)"
--
2.27.0
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