[Qemu-devel] [PATCH v7 10/13] vfio: Add load state functions to SaveVMHandlers

[Kirti Wankhede <kwankhede@nvidia.com>]

Flow during _RESUMING device state:
- If Vendor driver defines mappable region, mmap migration region.
- Load config state.
- For data packet, till VFIO_MIG_FLAG_END_OF_STATE is not reached
    - read data_size from packet, read buffer of data_size
    - read data_offset from where QEMU should write data.
        if region is mmaped, write data of data_size to mmaped region.
    - write data_size.
        In case of mmapped region, write to data_size indicates kernel
        driver that data is written in staging buffer.
    - if region is trapped, pwrite() data of data_size from data_offset.
- Repeat above until VFIO_MIG_FLAG_END_OF_STATE.
- Unmap migration region.

For user, data is opaque. User should write data in the same order as
received.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
---
 hw/vfio/migration.c  | 162 +++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/vfio/trace-events |   3 +
 2 files changed, 165 insertions(+)

diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 4e9b4cce230b..5fb4c5329ede 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -249,6 +249,26 @@ static int vfio_save_device_config_state(QEMUFile *f, void *opaque)
     return qemu_file_get_error(f);
 }
 
+static int vfio_load_device_config_state(QEMUFile *f, void *opaque)
+{
+    VFIODevice *vbasedev = opaque;
+    uint64_t data;
+
+    if (vbasedev->ops && vbasedev->ops->vfio_load_config) {
+        vbasedev->ops->vfio_load_config(vbasedev, f);
+    }
+
+    data = qemu_get_be64(f);
+    if (data != VFIO_MIG_FLAG_END_OF_STATE) {
+        error_report("%s: Failed loading device config space, "
+                     "end flag incorrect 0x%"PRIx64, vbasedev->name, data);
+        return -EINVAL;
+    }
+
+    trace_vfio_load_device_config_state(vbasedev->name);
+    return qemu_file_get_error(f);
+}
+
 /* ---------------------------------------------------------------------- */
 
 static int vfio_save_setup(QEMUFile *f, void *opaque)
@@ -421,12 +441,154 @@ static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
     return ret;
 }
 
+static int vfio_load_setup(QEMUFile *f, void *opaque)
+{
+    VFIODevice *vbasedev = opaque;
+    VFIOMigration *migration = vbasedev->migration;
+    int ret = 0;
+
+    if (migration->region.buffer.mmaps) {
+        ret = vfio_region_mmap(&migration->region.buffer);
+        if (ret) {
+            error_report("%s: Failed to mmap VFIO migration region %d: %s",
+                         vbasedev->name, migration->region.index,
+                         strerror(-ret));
+            return ret;
+        }
+    }
+
+    ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING);
+    if (ret) {
+        error_report("%s: Failed to set state RESUMING", vbasedev->name);
+    }
+    return ret;
+}
+
+static int vfio_load_cleanup(void *opaque)
+{
+    vfio_save_cleanup(opaque);
+    return 0;
+}
+
+static int vfio_load_state(QEMUFile *f, void *opaque, int version_id)
+{
+    VFIODevice *vbasedev = opaque;
+    VFIOMigration *migration = vbasedev->migration;
+    int ret = 0;
+    uint64_t data, data_size;
+
+    data = qemu_get_be64(f);
+    while (data != VFIO_MIG_FLAG_END_OF_STATE) {
+
+        trace_vfio_load_state(vbasedev->name, data);
+
+        switch (data) {
+        case VFIO_MIG_FLAG_DEV_CONFIG_STATE:
+        {
+            ret = vfio_load_device_config_state(f, opaque);
+            if (ret) {
+                return ret;
+            }
+            break;
+        }
+        case VFIO_MIG_FLAG_DEV_SETUP_STATE:
+        {
+            data = qemu_get_be64(f);
+            if (data == VFIO_MIG_FLAG_END_OF_STATE) {
+                return ret;
+            } else {
+                error_report("%s: SETUP STATE: EOS not found 0x%"PRIx64,
+                             vbasedev->name, data);
+                return -EINVAL;
+            }
+            break;
+        }
+        case VFIO_MIG_FLAG_DEV_DATA_STATE:
+        {
+            VFIORegion *region = &migration->region.buffer;
+            void *buf = NULL;
+            bool buffer_mmaped = false;
+            uint64_t data_offset = 0;
+
+            data_size = qemu_get_be64(f);
+            if (data_size == 0) {
+                break;
+            }
+
+            ret = pread(vbasedev->fd, &data_offset, sizeof(data_offset),
+                        region->fd_offset +
+                        offsetof(struct vfio_device_migration_info,
+                        data_offset));
+            if (ret != sizeof(data_offset)) {
+                error_report("%s:Failed to get migration buffer data offset %d",
+                             vbasedev->name, ret);
+                return -EINVAL;
+            }
+
+            if (region->mmaps) {
+                buf = find_data_region(region, data_offset, data_size);
+            }
+
+            buffer_mmaped = (buf != NULL) ? true : false;
+
+            if (!buffer_mmaped) {
+                buf = g_try_malloc0(data_size);
+                if (!buf) {
+                    error_report("%s: Error allocating buffer ", __func__);
+                    return -ENOMEM;
+                }
+            }
+
+            qemu_get_buffer(f, buf, data_size);
+
+            ret = pwrite(vbasedev->fd, &data_size, sizeof(data_size),
+                         region->fd_offset +
+                       offsetof(struct vfio_device_migration_info, data_size));
+            if (ret != sizeof(data_size)) {
+                error_report("%s: Failed to set migration buffer data size %d",
+                             vbasedev->name, ret);
+                if (!buffer_mmaped) {
+                    g_free(buf);
+                }
+                return -EINVAL;
+            }
+
+            if (!buffer_mmaped) {
+                ret = pwrite(vbasedev->fd, buf, data_size,
+                             region->fd_offset + data_offset);
+                g_free(buf);
+
+                if (ret != data_size) {
+                    error_report("%s: Failed to set migration buffer %d",
+                                 vbasedev->name, ret);
+                    return -EINVAL;
+                }
+            }
+            trace_vfio_load_state_device_data(vbasedev->name, data_offset,
+                                              data_size);
+            break;
+        }
+        }
+
+        ret = qemu_file_get_error(f);
+        if (ret) {
+            return ret;
+        }
+        data = qemu_get_be64(f);
+    }
+
+    return ret;
+}
+
 static SaveVMHandlers savevm_vfio_handlers = {
     .save_setup = vfio_save_setup,
     .save_cleanup = vfio_save_cleanup,
     .save_live_pending = vfio_save_pending,
     .save_live_iterate = vfio_save_iterate,
     .save_live_complete_precopy = vfio_save_complete_precopy,
+    .load_setup = vfio_load_setup,
+    .load_cleanup = vfio_load_cleanup,
+    .load_state = vfio_load_state,
 };
 
 /* ---------------------------------------------------------------------- */
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index bdf40ba368c7..ac065b559f4e 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -157,3 +157,6 @@ vfio_save_device_config_state(char *name) " (%s)"
 vfio_save_pending(char *name, uint64_t precopy, uint64_t postcopy, uint64_t compatible) " (%s) precopy 0x%"PRIx64" postcopy 0x%"PRIx64" compatible 0x%"PRIx64
 vfio_save_iterate(char *name, int data_size) " (%s) data_size %d"
 vfio_save_complete_precopy(char *name) " (%s)"
+vfio_load_device_config_state(char *name) " (%s)"
+vfio_load_state(char *name, uint64_t data) " (%s) data 0x%"PRIx64
+vfio_load_state_device_data(char *name, uint64_t data_offset, uint64_t data_size) " (%s) Offset 0x%"PRIx64" size 0x%"PRIx64
-- 
2.7.0