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Re: [PATCH QEMU v25 09/17] vfio: Add load state functions to SaveVMHandl
From: |
Alex Williamson |
Subject: |
Re: [PATCH QEMU v25 09/17] vfio: Add load state functions to SaveVMHandlers |
Date: |
Wed, 24 Jun 2020 12:54:37 -0600 |
On Sun, 21 Jun 2020 01:51:18 +0530
Kirti Wankhede <kwankhede@nvidia.com> wrote:
> Sequence during _RESUMING device state:
> While data for this device is available, repeat below steps:
> a. read data_offset from where user application should write data.
> b. write data of data_size to migration region from data_offset.
> c. write data_size which indicates vendor driver that data is written in
> staging buffer.
>
> 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>
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
> hw/vfio/migration.c | 177
> +++++++++++++++++++++++++++++++++++++++++++++++++++
> hw/vfio/trace-events | 3 +
> 2 files changed, 180 insertions(+)
>
> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> index ef1150c1ff02..faacea5327cb 100644
> --- a/hw/vfio/migration.c
> +++ b/hw/vfio/migration.c
> @@ -302,6 +302,33 @@ 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) {
> + int ret;
> +
> + ret = vbasedev->ops->vfio_load_config(vbasedev, f);
> + if (ret) {
> + error_report("%s: Failed to load device config space",
> + vbasedev->name);
> + return ret;
> + }
> + }
> +
> + 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)
> @@ -472,12 +499,162 @@ 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.mmaps) {
> + ret = vfio_region_mmap(&migration->region);
> + if (ret) {
> + error_report("%s: Failed to mmap VFIO migration region %d: %s",
> + vbasedev->name, migration->region.nr,
> + strerror(-ret));
> + return ret;
Not fatal.
> + }
> + }
> +
> + ret = vfio_migration_set_state(vbasedev, ~VFIO_DEVICE_STATE_MASK,
> + 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;
This is essentially just a compatibility failure, right? For instance
some future version of QEMU might include additional data between these
markers that we don't understand and therefore we fail the migration.
Thanks,
Alex
> + }
> + break;
> + }
> + case VFIO_MIG_FLAG_DEV_DATA_STATE:
> + {
> + VFIORegion *region = &migration->region;
> + uint64_t data_offset = 0, size;
> +
> + data_size = 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;
> + }
> +
> + trace_vfio_load_state_device_data(vbasedev->name, data_offset,
> + data_size);
> +
> + while (size) {
> + void *buf = NULL;
> + uint64_t sec_size;
> + bool buffer_mmaped;
> +
> + buf = get_data_section_size(region, data_offset, size,
> + &sec_size);
> +
> + buffer_mmaped = (buf != NULL);
> +
> + if (!buffer_mmaped) {
> + buf = g_try_malloc(sec_size);
> + if (!buf) {
> + error_report("%s: Error allocating buffer ",
> __func__);
> + return -ENOMEM;
> + }
> + }
> +
> + qemu_get_buffer(f, buf, sec_size);
> +
> + if (!buffer_mmaped) {
> + ret = pwrite(vbasedev->fd, buf, sec_size,
> + region->fd_offset + data_offset);
> + g_free(buf);
> +
> + if (ret != sec_size) {
> + error_report("%s: Failed to set migration buffer %d",
> + vbasedev->name, ret);
> + return -EINVAL;
> + }
> + }
> + size -= sec_size;
> + data_offset += sec_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);
> + return -EINVAL;
> + }
> + break;
> + }
> +
> + default:
> + error_report("%s: Unknown tag 0x%"PRIx64, vbasedev->name, data);
> + return -EINVAL;
> + }
> +
> + data = qemu_get_be64(f);
> + ret = qemu_file_get_error(f);
> + if (ret) {
> + return ret;
> + }
> + }
> +
> + 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 9a1c5e17d97f..4a4bd3ba9a2a 100644
> --- a/hw/vfio/trace-events
> +++ b/hw/vfio/trace-events
> @@ -157,3 +157,6 @@ vfio_save_device_config_state(const char *name) " (%s)"
> vfio_save_pending(const char *name, uint64_t precopy, uint64_t postcopy,
> uint64_t compatible) " (%s) precopy 0x%"PRIx64" postcopy 0x%"PRIx64"
> compatible 0x%"PRIx64
> vfio_save_iterate(const char *name, int data_size) " (%s) data_size %d"
> vfio_save_complete_precopy(const char *name) " (%s)"
> +vfio_load_device_config_state(const char *name) " (%s)"
> +vfio_load_state(const char *name, uint64_t data) " (%s) data 0x%"PRIx64
> +vfio_load_state_device_data(const char *name, uint64_t data_offset, uint64_t
> data_size) " (%s) Offset 0x%"PRIx64" size 0x%"PRIx64
- Re: [PATCH QEMU v25 07/17] vfio: Register SaveVMHandlers for VFIO device, (continued)
Re: [PATCH QEMU v25 07/17] vfio: Register SaveVMHandlers for VFIO device, Dr. David Alan Gilbert, 2020/06/26
[PATCH QEMU v25 08/17] vfio: Add save state functions to SaveVMHandlers, Kirti Wankhede, 2020/06/20
[PATCH QEMU v25 09/17] vfio: Add load state functions to SaveVMHandlers, Kirti Wankhede, 2020/06/20
[PATCH QEMU v25 10/17] memory: Set DIRTY_MEMORY_MIGRATION when IOMMU is enabled, Kirti Wankhede, 2020/06/20
[PATCH QEMU v25 11/17] vfio: Get migration capability flags for container, Kirti Wankhede, 2020/06/20
[PATCH QEMU v25 12/17] vfio: Add function to start and stop dirty pages tracking, Kirti Wankhede, 2020/06/20