Re: [RFC V1 10/12] migration/ram: old host address

[Fabiano Rosas]

Steve Sistare <steven.sistare@oracle.com> writes:

> Remember the RAMBlock host address as host_old during migration, for use
> by CPR.  The iommufd interface to update the virtual address of DMA
> mappings requires it.
>
> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
> ---
>  hw/core/machine.c       | 6 ++++++
>  include/exec/ramblock.h | 1 +
>  migration/migration.h   | 2 ++
>  migration/options.c     | 2 ++
>  migration/ram.c         | 7 +++++++
>  5 files changed, 18 insertions(+)
>
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index 9676953..0ac16b8 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -35,6 +35,12 @@
>  #include "hw/virtio/virtio-iommu.h"
>  #include "audio/audio.h"
>  
> +/* TBD: register hw_compat_9_1 with machines */
> +GlobalProperty hw_compat_9_1[] = {
> +    { "migration", "send-host-old", "off"},
> +};
> +const size_t hw_compat_9_1_len = G_N_ELEMENTS(hw_compat_9_1);
> +
>  GlobalProperty hw_compat_9_0[] = {
>      {"arm-cpu", "backcompat-cntfrq", "true" },
>      {"scsi-disk-base", "migrate-emulated-scsi-request", "false" },
> diff --git a/include/exec/ramblock.h b/include/exec/ramblock.h
> index 64484cd..8f1c535 100644
> --- a/include/exec/ramblock.h
> +++ b/include/exec/ramblock.h
> @@ -28,6 +28,7 @@ struct RAMBlock {
>      struct rcu_head rcu;
>      struct MemoryRegion *mr;
>      uint8_t *host;
> +    uint64_t host_old;
>      uint8_t *colo_cache; /* For colo, VM's ram cache */
>      ram_addr_t offset;
>      ram_addr_t used_length;
> diff --git a/migration/migration.h b/migration/migration.h
> index 38aa140..b5e3151 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -442,6 +442,8 @@ struct MigrationState {
>       */
>      uint8_t clear_bitmap_shift;
>  
> +    bool send_host_old;
> +
>      /*
>       * This save hostname when out-going migration starts
>       */
> diff --git a/migration/options.c b/migration/options.c
> index 7526f9f..197cb86 100644
> --- a/migration/options.c
> +++ b/migration/options.c
> @@ -92,6 +92,8 @@ Property migration_properties[] = {
>                        clear_bitmap_shift, CLEAR_BITMAP_SHIFT_DEFAULT),
>      DEFINE_PROP_BOOL("x-preempt-pre-7-2", MigrationState,
>                       preempt_pre_7_2, false),
> +    DEFINE_PROP_BOOL("send-host-old", MigrationState,
> +                     send_host_old, true),
>  
>      /* Migration parameters */
>      DEFINE_PROP_UINT8("x-throttle-trigger-threshold", MigrationState,
> diff --git a/migration/ram.c b/migration/ram.c
> index 1e1e05e..8644917 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -3030,6 +3030,9 @@ static int ram_save_setup(QEMUFile *f, void *opaque, 
> Error **errp)
>              qemu_put_byte(f, strlen(block->idstr));
>              qemu_put_buffer(f, (uint8_t *)block->idstr, 
> strlen(block->idstr));
>              qemu_put_be64(f, block->used_length);
> +            if (migrate_get_current()->send_host_old) {
> +                qemu_put_be64(f, (uint64_t)block->host);
> +            }

This requires an update of scripts/analyze-migration.py. Could be done
on the side.

>              if (migrate_postcopy_ram() &&
>                  block->page_size != max_hg_page_size) {
>                  qemu_put_be64(f, block->page_size);
> @@ -4021,6 +4024,10 @@ static int parse_ramblock(QEMUFile *f, RAMBlock 
> *block, ram_addr_t length)
>  
>      assert(block);
>  
> +    if (migrate_get_current()->send_host_old) {
> +        block->host_old = qemu_get_be64(f);
> +    }
> +
>      if (migrate_mapped_ram()) {
>          parse_ramblock_mapped_ram(f, block, length, &local_err);
>          if (local_err) {