[PATCH 5/5] vfio/migration: support device memory capability
Christophe de Dinechin
cdupontd at redhat.com
Tue Feb 19 14:42:36 UTC 2019
> On 19 Feb 2019, at 09:53, Yan Zhao <yan.y.zhao at intel.com> wrote:
>
> If a device has device memory capability, save/load data from device memory
> in pre-copy and stop-and-copy phases.
>
> LOGGING state is set for device memory for dirty page logging:
> in LOGGING state, get device memory returns whole device memory snapshot;
> outside LOGGING state, get device memory returns dirty data since last get
> operation.
>
> Usually, device memory is very big, qemu needs to chunk it into several
> pieces each with size of device memory region.
>
> Signed-off-by: Yan Zhao <yan.y.zhao at intel.com>
> Signed-off-by: Kirti Wankhede <kwankhede at nvidia.com>
> ---
> hw/vfio/migration.c | 235 ++++++++++++++++++++++++++++++++++++++++++++++++++--
> hw/vfio/pci.h | 1 +
> 2 files changed, 231 insertions(+), 5 deletions(-)
>
> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> index 16d6395..f1e9309 100644
> --- a/hw/vfio/migration.c
> +++ b/hw/vfio/migration.c
> @@ -203,6 +203,201 @@ static int vfio_load_data_device_config(VFIOPCIDevice *vdev,
> return 0;
> }
>
> +static int vfio_get_device_memory_size(VFIOPCIDevice *vdev)
> +{
> + VFIODevice *vbasedev = &vdev->vbasedev;
> + VFIORegion *region_ctl =
> + &vdev->migration->region[VFIO_DEVSTATE_REGION_CTL];
> + uint64_t len;
> + int sz;
> +
> + sz = sizeof(len);
> + if (pread(vbasedev->fd, &len, sz,
> + region_ctl->fd_offset +
> + offsetof(struct vfio_device_state_ctl, device_memory.size))
> + != sz) {
> + error_report("vfio: Failed to get length of device memory”);
s/length/size/ ? (to be consistent with function name)
> + return -1;
> + }
> + vdev->migration->devmem_size = len;
> + return 0;
> +}
> +
> +static int vfio_set_device_memory_size(VFIOPCIDevice *vdev, uint64_t size)
> +{
> + VFIODevice *vbasedev = &vdev->vbasedev;
> + VFIORegion *region_ctl =
> + &vdev->migration->region[VFIO_DEVSTATE_REGION_CTL];
> + int sz;
> +
> + sz = sizeof(size);
> + if (pwrite(vbasedev->fd, &size, sz,
> + region_ctl->fd_offset +
> + offsetof(struct vfio_device_state_ctl, device_memory.size))
> + != sz) {
> + error_report("vfio: Failed to set length of device comemory”);
What is comemory? Typo?
Same comment about length vs size
> + return -1;
> + }
> + vdev->migration->devmem_size = size;
> + return 0;
> +}
> +
> +static
> +int vfio_save_data_device_memory_chunk(VFIOPCIDevice *vdev, QEMUFile *f,
> + uint64_t pos, uint64_t len)
> +{
> + VFIODevice *vbasedev = &vdev->vbasedev;
> + VFIORegion *region_ctl =
> + &vdev->migration->region[VFIO_DEVSTATE_REGION_CTL];
> + VFIORegion *region_devmem =
> + &vdev->migration->region[VFIO_DEVSTATE_REGION_DATA_DEVICE_MEMORY];
> + void *dest;
> + uint32_t sz;
> + uint8_t *buf = NULL;
> + uint32_t action = VFIO_DEVICE_DATA_ACTION_GET_BUFFER;
> +
> + if (len > region_devmem->size) {
Is it intentional that there is no error_report here?
> + return -1;
> + }
> +
> + sz = sizeof(pos);
> + if (pwrite(vbasedev->fd, &pos, sz,
> + region_ctl->fd_offset +
> + offsetof(struct vfio_device_state_ctl, device_memory.pos))
> + != sz) {
> + error_report("vfio: Failed to set save buffer pos");
> + return -1;
> + }
> + sz = sizeof(action);
> + if (pwrite(vbasedev->fd, &action, sz,
> + region_ctl->fd_offset +
> + offsetof(struct vfio_device_state_ctl, device_memory.action))
> + != sz) {
> + error_report("vfio: Failed to set save buffer action");
> + return -1;
> + }
> +
> + if (!vfio_device_state_region_mmaped(region_devmem)) {
> + buf = g_malloc(len);
> + if (buf == NULL) {
> + error_report("vfio: Failed to allocate memory for migrate”);
s/migrate/migration/ ?
> + return -1;
> + }
> + if (pread(vbasedev->fd, buf, len, region_devmem->fd_offset) != len) {
> + error_report("vfio: error load device memory buffer”);
s/load/loading/ ?
> + return -1;
> + }
> + qemu_put_be64(f, len);
> + qemu_put_be64(f, pos);
> + qemu_put_buffer(f, buf, len);
> + g_free(buf);
> + } else {
> + dest = region_devmem->mmaps[0].mmap;
> + qemu_put_be64(f, len);
> + qemu_put_be64(f, pos);
> + qemu_put_buffer(f, dest, len);
> + }
> + return 0;
> +}
> +
> +static int vfio_save_data_device_memory(VFIOPCIDevice *vdev, QEMUFile *f)
> +{
> + VFIORegion *region_devmem =
> + &vdev->migration->region[VFIO_DEVSTATE_REGION_DATA_DEVICE_MEMORY];
> + uint64_t total_len = vdev->migration->devmem_size;
> + uint64_t pos = 0;
> +
> + qemu_put_be64(f, total_len);
> + while (pos < total_len) {
> + uint64_t len = region_devmem->size;
> +
> + if (pos + len >= total_len) {
> + len = total_len - pos;
> + }
> + if (vfio_save_data_device_memory_chunk(vdev, f, pos, len)) {
> + return -1;
> + }
I don’t see where pos is incremented in this loop
> + }
> +
> + return 0;
> +}
> +
> +static
> +int vfio_load_data_device_memory_chunk(VFIOPCIDevice *vdev, QEMUFile *f,
> + uint64_t pos, uint64_t len)
> +{
> + VFIODevice *vbasedev = &vdev->vbasedev;
> + VFIORegion *region_ctl =
> + &vdev->migration->region[VFIO_DEVSTATE_REGION_CTL];
> + VFIORegion *region_devmem =
> + &vdev->migration->region[VFIO_DEVSTATE_REGION_DATA_DEVICE_MEMORY];
> +
> + void *dest;
> + uint32_t sz;
> + uint8_t *buf = NULL;
> + uint32_t action = VFIO_DEVICE_DATA_ACTION_SET_BUFFER;
> +
> + if (len > region_devmem->size) {
error_report?
> + return -1;
> + }
> +
> + sz = sizeof(pos);
> + if (pwrite(vbasedev->fd, &pos, sz,
> + region_ctl->fd_offset +
> + offsetof(struct vfio_device_state_ctl, device_memory.pos))
> + != sz) {
> + error_report("vfio: Failed to set device memory buffer pos");
> + return -1;
> + }
> + if (!vfio_device_state_region_mmaped(region_devmem)) {
> + buf = g_malloc(len);
> + if (buf == NULL) {
> + error_report("vfio: Failed to allocate memory for migrate");
> + return -1;
> + }
> + qemu_get_buffer(f, buf, len);
> + if (pwrite(vbasedev->fd, buf, len,
> + region_devmem->fd_offset) != len) {
> + error_report("vfio: Failed to load devie memory buffer");
> + return -1;
> + }
> + g_free(buf);
> + } else {
> + dest = region_devmem->mmaps[0].mmap;
> + qemu_get_buffer(f, dest, len);
> + }
> +
> + sz = sizeof(action);
> + if (pwrite(vbasedev->fd, &action, sz,
> + region_ctl->fd_offset +
> + offsetof(struct vfio_device_state_ctl, device_memory.action))
> + != sz) {
> + error_report("vfio: Failed to set load device memory buffer action");
> + return -1;
> + }
> +
> + return 0;
> +
> +}
> +
> +static int vfio_load_data_device_memory(VFIOPCIDevice *vdev,
> + QEMUFile *f, uint64_t total_len)
> +{
> + uint64_t pos = 0, len = 0;
> +
> + vfio_set_device_memory_size(vdev, total_len);
> +
> + while (pos + len < total_len) {
> + len = qemu_get_be64(f);
> + pos = qemu_get_be64(f);
Nit: load reads len/pos in the loop, whereas save does it in the
inner function (vfio_save_data_device_memory_chunk)
> +
> + vfio_load_data_device_memory_chunk(vdev, f, pos, len);
> + }
> +
> + return 0;
> +}
> +
> +
> static int vfio_set_dirty_page_bitmap_chunk(VFIOPCIDevice *vdev,
> uint64_t start_addr, uint64_t page_nr)
> {
> @@ -377,6 +572,10 @@ static void vfio_save_live_pending(QEMUFile *f, void *opaque,
> return;
> }
>
> + /* get dirty data size of device memory */
> + vfio_get_device_memory_size(vdev);
> +
> + *res_precopy_only += vdev->migration->devmem_size;
> return;
> }
>
> @@ -388,7 +587,9 @@ static int vfio_save_iterate(QEMUFile *f, void *opaque)
> return 0;
> }
>
> - return 0;
> + qemu_put_byte(f, VFIO_SAVE_FLAG_DEVMEMORY);
> + /* get dirty data of device memory */
> + return vfio_save_data_device_memory(vdev, f);
> }
>
> static void vfio_pci_load_config(VFIOPCIDevice *vdev, QEMUFile *f)
> @@ -458,6 +659,10 @@ static int vfio_load_state(QEMUFile *f, void *opaque, int version_id)
> len = qemu_get_be64(f);
> vfio_load_data_device_config(vdev, f, len);
> break;
> + case VFIO_SAVE_FLAG_DEVMEMORY:
> + len = qemu_get_be64(f);
> + vfio_load_data_device_memory(vdev, f, len);
> + break;
> default:
> ret = -EINVAL;
> }
> @@ -503,6 +708,13 @@ static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
> VFIOPCIDevice *vdev = opaque;
> int rc = 0;
>
> + if (vfio_device_data_cap_device_memory(vdev)) {
> + qemu_put_byte(f, VFIO_SAVE_FLAG_DEVMEMORY | VFIO_SAVE_FLAG_CONTINUE);
> + /* get dirty data of device memory */
> + vfio_get_device_memory_size(vdev);
> + rc = vfio_save_data_device_memory(vdev, f);
> + }
> +
> qemu_put_byte(f, VFIO_SAVE_FLAG_PCI | VFIO_SAVE_FLAG_CONTINUE);
> vfio_pci_save_config(vdev, f);
>
> @@ -515,12 +727,22 @@ static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
>
> static int vfio_save_setup(QEMUFile *f, void *opaque)
> {
> + int rc = 0;
> VFIOPCIDevice *vdev = opaque;
> - qemu_put_byte(f, VFIO_SAVE_FLAG_SETUP);
> +
> + if (vfio_device_data_cap_device_memory(vdev)) {
> + qemu_put_byte(f, VFIO_SAVE_FLAG_SETUP | VFIO_SAVE_FLAG_CONTINUE);
> + qemu_put_byte(f, VFIO_SAVE_FLAG_DEVMEMORY);
> + /* get whole snapshot of device memory */
> + vfio_get_device_memory_size(vdev);
> + rc = vfio_save_data_device_memory(vdev, f);
> + } else {
> + qemu_put_byte(f, VFIO_SAVE_FLAG_SETUP);
> + }
>
> vfio_set_device_state(vdev, VFIO_DEVICE_STATE_RUNNING |
> VFIO_DEVICE_STATE_LOGGING);
> - return 0;
> + return rc;
> }
>
> static int vfio_load_setup(QEMUFile *f, void *opaque)
> @@ -576,8 +798,11 @@ int vfio_migration_init(VFIOPCIDevice *vdev, Error **errp)
> goto error;
> }
>
> - if (vfio_device_data_cap_device_memory(vdev)) {
> - error_report("No suppport of data cap device memory Yet");
> + if (vfio_device_data_cap_device_memory(vdev) &&
> + vfio_device_state_region_setup(vdev,
> + &vdev->migration->region[VFIO_DEVSTATE_REGION_DATA_DEVICE_MEMORY],
> + VFIO_REGION_SUBTYPE_DEVICE_STATE_DATA_MEMORY,
> + "device-state-data-device-memory")) {
> goto error;
> }
>
> diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
> index 4b7b1bb..a2cc64b 100644
> --- a/hw/vfio/pci.h
> +++ b/hw/vfio/pci.h
> @@ -69,6 +69,7 @@ typedef struct VFIOMigration {
> uint32_t data_caps;
> uint32_t device_state;
> uint64_t devconfig_size;
> + uint64_t devmem_size;
> VMChangeStateEntry *vm_state;
> } VFIOMigration;
>
> --
> 2.7.4
>
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