diff options
| -rw-r--r-- | qapi/migration.json | 35 |
1 files changed, 22 insertions, 13 deletions
diff --git a/qapi/migration.json b/qapi/migration.json index 7303e57e8e..bee5e71fe3 100644 --- a/qapi/migration.json +++ b/qapi/migration.json @@ -636,19 +636,28 @@ # # @normal: the original form of migration. (since 8.2) # -# @cpr-reboot: The migrate command saves state to a file, allowing one to -# quit qemu, reboot to an updated kernel, and restart an updated -# version of qemu. The caller must specify a migration URI -# that writes to and reads from a file. Unlike normal mode, -# the use of certain local storage options does not block the -# migration, but the caller must not modify guest block devices -# between the quit and restart. To avoid saving guest RAM to the -# file, the memory backend must be shared, and the @x-ignore-shared -# migration capability must be set. Guest RAM must be non-volatile -# across reboot, such as by backing it with a dax device, but this -# is not enforced. The restarted qemu arguments must match those -# used to initially start qemu, plus the -incoming option. -# (since 8.2) +# @cpr-reboot: The migrate command stops the VM and saves state to the URI. +# After quitting qemu, the user resumes by running qemu -incoming. +# +# This mode allows the user to quit qemu, and restart an updated version +# of qemu. The user may even update and reboot the OS before restarting, +# as long as the URI persists across a reboot. +# +# Unlike normal mode, the use of certain local storage options does not +# block the migration, but the user must not modify guest block devices +# between the quit and restart. +# +# This mode supports vfio devices provided the user first puts the guest +# in the suspended runstate, such as by issuing guest-suspend-ram to the +# qemu guest agent. +# +# Best performance is achieved when the memory backend is shared and the +# @x-ignore-shared migration capability is set, but this is not required. +# Further, if the user reboots before restarting such a configuration, the +# shared backend must be be non-volatile across reboot, such as by backing +# it with a dax device. +# +# (since 8.2) ## { 'enum': 'MigMode', 'data': [ 'normal', 'cpr-reboot' ] } |