| Message ID | 1708622920-68779-14-git-send-email-steven.sistare@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | allow cpr-reboot for vfio | expand |
On Thu, Feb 22, 2024 at 09:28:39AM -0800, Steve Sistare wrote: > Clarify qapi for cpr-reboot migration mode, and add vfio support. > > Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Reviewed-by: Peter Xu <peterx@redhat.com>
Steve Sistare <steven.sistare@oracle.com> writes: > Clarify qapi for cpr-reboot migration mode, and add vfio support. The patch only affects documentation, but that's less than clear from the commit message. Suggest Improve documentation for migration mode @cpr-reboot. In particular, document VFIO support. > Signed-off-by: Steve Sistare <steven.sistare@oracle.com> > --- > qapi/migration.json | 35 ++++++++++++++++++++++------------- > 1 file changed, 22 insertions(+), 13 deletions(-) > > diff --git a/qapi/migration.json b/qapi/migration.json > index 5a565d9..0990297 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. These two sentences apply to any migration mode, don't they? Just checking I understand. > +# > +# 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. Hmm, doesn't normal migration also support migrating to a newer QEMU? > +# > +# 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. "Must not modify the contents of the guest block devices"? > +# > +# This mode supports vfio devices provided the user first puts the guest "VFIO devices" > +# 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 Typo: "be be non-volatile" Suggest "the shared memory must persist" > +# it with a dax device. > +# > +# (since 8.2) > ## > { 'enum': 'MigMode', > 'data': [ 'normal', 'cpr-reboot' ] } Thanks for adjusting indentation to conform to conventions. Please additionally reflow the text to limit line length to 70 characters.
diff --git a/qapi/migration.json b/qapi/migration.json index 5a565d9..0990297 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' ] }
Clarify qapi for cpr-reboot migration mode, and add vfio support. Signed-off-by: Steve Sistare <steven.sistare@oracle.com> --- qapi/migration.json | 35 ++++++++++++++++++++++------------- 1 file changed, 22 insertions(+), 13 deletions(-)