| Message ID | 1705071910-174321-1-git-send-email-steven.sistare@oracle.com |
|---|---|
| Headers | show |
| Series | allow cpr-reboot for vfio | expand |
On Fri, 12 Jan 2024 07:04:59 -0800 Steve Sistare <steven.sistare@oracle.com> wrote: > Allow cpr-reboot for vfio if the guest is in the suspended runstate. The > guest drivers' suspend methods flush outstanding requests and re-initialize > the devices, and thus there is no device state to save and restore. The > user is responsible for suspending the guest before initiating cpr, such as > by issuing guest-suspend-ram to the qemu guest agent. > > Most of the patches in this series enhance migration notifiers so they can > return an error status and message. The last two patches register a notifier > for vfio that returns an error if the guest is not suspended. Hi Steve, This appears to only support legacy container mode and not cdev/iommufd mode. Shouldn't this support both? Thanks, Alex > Steve Sistare (11): > notify: pass error to notifier with return > migration: remove error from notifier data > migration: convert to NotifierWithReturn > migration: remove migration_in_postcopy parameter > migration: MigrationEvent for notifiers > migration: MigrationNotifyFunc > migration: per-mode notifiers > migration: refactor migrate_fd_connect failures > migration: notifier error checking > vfio: register container for cpr > vfio: allow cpr-reboot migration if suspended > > hw/net/virtio-net.c | 14 ++--- > hw/vfio/common.c | 2 +- > hw/vfio/container.c | 11 +++- > hw/vfio/cpr.c | 39 ++++++++++++++ > hw/vfio/meson.build | 1 + > hw/vfio/migration.c | 13 +++-- > hw/virtio/vhost-user.c | 10 ++-- > hw/virtio/virtio-balloon.c | 3 +- > include/hw/vfio/vfio-common.h | 6 ++- > include/hw/virtio/virtio-net.h | 2 +- > include/migration/misc.h | 21 +++++--- > include/qemu/notify.h | 7 ++- > migration/migration.c | 117 +++++++++++++++++++++++++++-------------- > migration/postcopy-ram.c | 3 +- > migration/postcopy-ram.h | 1 - > migration/ram.c | 12 ++--- > net/vhost-vdpa.c | 15 +++--- > ui/spice-core.c | 19 +++---- > util/notify.c | 5 +- > 19 files changed, 206 insertions(+), 95 deletions(-) > create mode 100644 hw/vfio/cpr.c >
On 12.01.24 16:04, Steve Sistare wrote: > Allow cpr-reboot for vfio if the guest is in the suspended runstate. The > guest drivers' suspend methods flush outstanding requests and re-initialize > the devices, and thus there is no device state to save and restore. The > user is responsible for suspending the guest before initiating cpr, such as > by issuing guest-suspend-ram to the qemu guest agent. Can you briefly explain what cpr-reboot is, or do you have a pointer to some more details? What is is good for, why would you use it, how does it work? I *suspect* that you want to live-migrate a VM with vfio devices attached, whereby you don't want to migrate device state.
On 15.01.24 11:48, David Hildenbrand wrote: > On 12.01.24 16:04, Steve Sistare wrote: >> Allow cpr-reboot for vfio if the guest is in the suspended runstate. The >> guest drivers' suspend methods flush outstanding requests and re-initialize >> the devices, and thus there is no device state to save and restore. The >> user is responsible for suspending the guest before initiating cpr, such as >> by issuing guest-suspend-ram to the qemu guest agent. > > Can you briefly explain what cpr-reboot is, or do you have a pointer to > some more details? > > What is is good for, why would you use it, how does it work? > > I *suspect* that you want to live-migrate a VM with vfio devices > attached, whereby you don't want to migrate device state. > Ah, found it: +# @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) I'll note that the use of "reboot" is extremely confusing in this context. You *might* want to reboot the hypervisor, but that's actually completely independent from the QEMU implementation.
On 1/12/2024 4:38 PM, Alex Williamson wrote: > On Fri, 12 Jan 2024 07:04:59 -0800 > Steve Sistare <steven.sistare@oracle.com> wrote: > >> Allow cpr-reboot for vfio if the guest is in the suspended runstate. The >> guest drivers' suspend methods flush outstanding requests and re-initialize >> the devices, and thus there is no device state to save and restore. The >> user is responsible for suspending the guest before initiating cpr, such as >> by issuing guest-suspend-ram to the qemu guest agent. >> >> Most of the patches in this series enhance migration notifiers so they can >> return an error status and message. The last two patches register a notifier >> for vfio that returns an error if the guest is not suspended. > > Hi Steve, > > This appears to only support legacy container mode and not cdev/iommufd > mode. Shouldn't this support both? Thanks, My bad, thanks! I'll move cpr_reboot_notifier to the base container, and also call cpr register/unregister from iommufd_cdev_attach/iommufd_cdev_detach. - Steve >> Steve Sistare (11): >> notify: pass error to notifier with return >> migration: remove error from notifier data >> migration: convert to NotifierWithReturn >> migration: remove migration_in_postcopy parameter >> migration: MigrationEvent for notifiers >> migration: MigrationNotifyFunc >> migration: per-mode notifiers >> migration: refactor migrate_fd_connect failures >> migration: notifier error checking >> vfio: register container for cpr >> vfio: allow cpr-reboot migration if suspended >> >> hw/net/virtio-net.c | 14 ++--- >> hw/vfio/common.c | 2 +- >> hw/vfio/container.c | 11 +++- >> hw/vfio/cpr.c | 39 ++++++++++++++ >> hw/vfio/meson.build | 1 + >> hw/vfio/migration.c | 13 +++-- >> hw/virtio/vhost-user.c | 10 ++-- >> hw/virtio/virtio-balloon.c | 3 +- >> include/hw/vfio/vfio-common.h | 6 ++- >> include/hw/virtio/virtio-net.h | 2 +- >> include/migration/misc.h | 21 +++++--- >> include/qemu/notify.h | 7 ++- >> migration/migration.c | 117 +++++++++++++++++++++++++++-------------- >> migration/postcopy-ram.c | 3 +- >> migration/postcopy-ram.h | 1 - >> migration/ram.c | 12 ++--- >> net/vhost-vdpa.c | 15 +++--- >> ui/spice-core.c | 19 +++---- >> util/notify.c | 5 +- >> 19 files changed, 206 insertions(+), 95 deletions(-) >> create mode 100644 hw/vfio/cpr.c >> >