From: Steven Sistare <steven.sistare@oracle.com>
To: "Michael S. Tsirkin" <mst@redhat.com>,
Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Cc: "Daniel P. Berrange" <berrange@redhat.com>,
"Juan Quintela" <quintela@redhat.com>,
"Jason Zeng" <jason.zeng@linux.intel.com>,
"Alex Bennée" <alex.bennee@linaro.org>,
qemu-devel <qemu-devel@nongnu.org>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
"Alex Williamson" <alex.williamson@redhat.com>,
"Stefan Hajnoczi" <stefanha@redhat.com>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Philippe Mathieu-Daudé" <philmd@redhat.com>,
"Markus Armbruster" <armbru@redhat.com>
Subject: Re: [PATCH V3 00/22] Live Update
Date: Wed, 2 Jun 2021 11:19:08 -0400 [thread overview]
Message-ID: <ca27f264-7aaf-a186-9c1b-5ee068b8268f@oracle.com> (raw)
In-Reply-To: <5bcabed6-82cd-3b84-9999-dd5ab2198a14@oracle.com>
Hi Michael,
Alex has reviewed the vfio-pci patches. If you could give me a thumbs-up or a
needs-work on "pci: export functions for cpr", I would appreciate it. Thanks!
[PATCH V3 10/22] pci: export functions for cpr
https://lore.kernel.org/qemu-devel/1620390320-301716-11-git-send-email-steven.sistare@oracle.com
- Steve
On 5/19/2021 12:43 PM, Steven Sistare wrote:
> Hi Michael, Marcel,
> I hope you have time to review the pci and vfio-pci related patches in this
> series. They are an essential part of the live update functionality. The
> first 2 patches are straightforward, just exposing functions for use in vfio.
> The last 2 patches are more substantial.
>
> - pci: export functions for cpr
> - vfio-pci: refactor for cpr
> - vfio-pci: cpr part 1
> - vfio-pci: cpr part 2
>
> - Steve
>
> On 5/7/2021 8:24 AM, Steve Sistare wrote:
>> Provide the cprsave and cprload commands for live update. These save and
>> restore VM state, with minimal guest pause time, so that qemu may be updated
>> to a new version in between.
>>
>> cprsave stops the VM and saves vmstate to an ordinary file. It supports two
>> modes: restart and reboot. For restart, cprsave exec's the qemu binary (or
>> /usr/bin/qemu-exec if it exists) with the same argv. qemu restarts in a
>> paused state and waits for the cprload command.
>>
>> To use the restart mode, qemu must be started with the memfd-alloc option,
>> which allocates guest ram using memfd_create. The memfd's are saved to
>> the environment and kept open across exec, after which they are found from
>> the environment and re-mmap'd. Hence guest ram is preserved in place,
>> albeit with new virtual addresses in the qemu process. The caller resumes
>> the guest by calling cprload, which loads state from the file. If the VM
>> was running at cprsave time, then VM execution resumes. cprsave supports
>> any type of guest image and block device, but the caller must not modify
>> guest block devices between cprsave and cprload.
>>
>> The restart mode supports vfio devices by preserving the vfio container,
>> group, device, and event descriptors across the qemu re-exec, and by
>> updating DMA mapping virtual addresses using VFIO_DMA_UNMAP_FLAG_VADDR and
>> VFIO_DMA_MAP_FLAG_VADDR as defined in https://lore.kernel.org/kvm/1611939252-7240-1-git-send-email-steven.sistare@oracle.com/
>> and integrated in Linux kernel 5.12.
>>
>> For the reboot mode, cprsave saves state and exits qemu, and the caller is
>> allowed to update the host kernel and system software and reboot. The
>> caller resumes the guest by running qemu with the same arguments as the
>> original process and calling cprload. To use this mode, guest ram must be
>> mapped to a persistent shared memory file such as /dev/dax0.0, or /dev/shm
>> PKRAM as proposed in https://lore.kernel.org/lkml/1617140178-8773-1-git-send-email-anthony.yznaga@oracle.com.
>>
>> The reboot mode supports vfio devices if the caller suspends the guest
>> instead of stopping the VM, such as by issuing guest-suspend-ram to the
>> qemu guest agent. 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 first patches add helper functions:
>>
>> - as_flat_walk
>> - qemu_ram_volatile
>> - oslib: qemu_clr_cloexec
>> - util: env var helpers
>> - machine: memfd-alloc option
>> - vl: add helper to request re-exec
>>
>> The next patches implement cprsave and cprload:
>>
>> - cpr
>> - cpr: QMP interfaces
>> - cpr: HMP interfaces
>>
>> The next patches add vfio support for the restart mode:
>>
>> - pci: export functions for cpr
>> - vfio-pci: refactor for cpr
>> - vfio-pci: cpr part 1
>> - vfio-pci: cpr part 2
>>
>> The next patches preserve various descriptor-based backend devices across
>> a cprsave restart:
>>
>> - vhost: reset vhost devices upon cprsave
>> - hostmem-memfd: cpr support
>> - chardev: cpr framework
>> - chardev: cpr for simple devices
>> - chardev: cpr for pty
>> - chardev: cpr for sockets
>> - cpr: only-cpr-capable option
>> - cpr: maintainers
>> - simplify savevm
>>
>> Here is an example of updating qemu from v4.2.0 to v4.2.1 using
>> "cprload restart". The software update is performed while the guest is
>> running to minimize downtime.
>>
>> window 1 | window 2
>> |
>> # qemu-system-x86_64 ... |
>> QEMU 4.2.0 monitor - type 'help' ... |
>> (qemu) info status |
>> VM status: running |
>> | # yum update qemu
>> (qemu) cprsave /tmp/qemu.sav restart |
>> QEMU 4.2.1 monitor - type 'help' ... |
>> (qemu) info status |
>> VM status: paused (prelaunch) |
>> (qemu) cprload /tmp/qemu.sav |
>> (qemu) info status |
>> VM status: running |
>>
>>
>> Here is an example of updating the host kernel using "cprload reboot"
>>
>> window 1 | window 2
>> |
>> # qemu-system-x86_64 ...mem-path=/dev/dax0.0 ...|
>> QEMU 4.2.1 monitor - type 'help' ... |
>> (qemu) info status |
>> VM status: running |
>> | # yum update kernel-uek
>> (qemu) cprsave /tmp/qemu.sav restart |
>> |
>> # systemctl kexec |
>> kexec_core: Starting new kernel |
>> ... |
>> |
>> # qemu-system-x86_64 ...mem-path=/dev/dax0.0 ...|
>> QEMU 4.2.1 monitor - type 'help' ... |
>> (qemu) info status |
>> VM status: paused (prelaunch) |
>> (qemu) cprload /tmp/qemu.sav |
>> (qemu) info status |
>> VM status: running |
>>
>> Changes from V1 to V2:
>> - revert vmstate infrastructure changes
>> - refactor cpr functions into new files
>> - delete MADV_DOEXEC and use memfd + VFIO_DMA_UNMAP_FLAG_SUSPEND to
>> preserve memory.
>> - add framework to filter chardev's that support cpr
>> - save and restore vfio eventfd's
>> - modify cprinfo QMP interface
>> - incorporate misc review feedback
>> - remove unrelated and unneeded patches
>> - refactor all patches into a shorter and easier to review series
>>
>> Changes from V2 to V3:
>> - rebase to qemu 6.0.0
>> - use final definition of vfio ioctls (VFIO_DMA_UNMAP_FLAG_VADDR etc)
>> - change memfd-alloc to a machine option
>> - use existing channel socket function instead of defining new ones
>> - close monitor socket during cpr
>> - support memory-backend-memfd
>> - fix a few unreported bugs
>>
>> Steve Sistare (18):
>> as_flat_walk
>> qemu_ram_volatile
>> oslib: qemu_clr_cloexec
>> util: env var helpers
>> machine: memfd-alloc option
>> vl: add helper to request re-exec
>> cpr
>> pci: export functions for cpr
>> vfio-pci: refactor for cpr
>> vfio-pci: cpr part 1
>> vfio-pci: cpr part 2
>> hostmem-memfd: cpr support
>> chardev: cpr framework
>> chardev: cpr for simple devices
>> chardev: cpr for pty
>> cpr: only-cpr-capable option
>> cpr: maintainers
>> simplify savevm
>>
>> Mark Kanda, Steve Sistare (4):
>> cpr: QMP interfaces
>> cpr: HMP interfaces
>> vhost: reset vhost devices upon cprsave
>> chardev: cpr for sockets
>>
>> MAINTAINERS | 11 +++
>> backends/hostmem-memfd.c | 21 +++--
>> chardev/char-mux.c | 1 +
>> chardev/char-null.c | 1 +
>> chardev/char-pty.c | 15 ++-
>> chardev/char-serial.c | 1 +
>> chardev/char-socket.c | 35 +++++++
>> chardev/char-stdio.c | 8 ++
>> chardev/char.c | 41 +++++++-
>> gdbstub.c | 1 +
>> hmp-commands.hx | 44 +++++++++
>> hw/core/machine.c | 19 ++++
>> hw/pci/msi.c | 4 +
>> hw/pci/msix.c | 20 ++--
>> hw/pci/pci.c | 7 +-
>> hw/vfio/common.c | 68 +++++++++++++-
>> hw/vfio/cpr.c | 131 ++++++++++++++++++++++++++
>> hw/vfio/meson.build | 1 +
>> hw/vfio/pci.c | 214 ++++++++++++++++++++++++++++++++++++++----
>> hw/vfio/trace-events | 1 +
>> hw/virtio/vhost.c | 11 +++
>> include/chardev/char.h | 6 ++
>> include/exec/memory.h | 25 +++++
>> include/hw/boards.h | 1 +
>> include/hw/pci/msix.h | 5 +
>> include/hw/pci/pci.h | 2 +
>> include/hw/vfio/vfio-common.h | 8 ++
>> include/hw/virtio/vhost.h | 1 +
>> include/migration/cpr.h | 17 ++++
>> include/monitor/hmp.h | 3 +
>> include/qemu/env.h | 23 +++++
>> include/qemu/osdep.h | 1 +
>> include/sysemu/runstate.h | 2 +
>> include/sysemu/sysemu.h | 2 +
>> linux-headers/linux/vfio.h | 27 ++++++
>> migration/cpr.c | 200 +++++++++++++++++++++++++++++++++++++++
>> migration/meson.build | 1 +
>> migration/migration.c | 5 +
>> migration/savevm.c | 21 ++---
>> migration/savevm.h | 2 +
>> monitor/hmp-cmds.c | 48 ++++++++++
>> monitor/hmp.c | 3 +
>> monitor/qmp-cmds.c | 31 ++++++
>> monitor/qmp.c | 3 +
>> qapi/char.json | 5 +-
>> qapi/cpr.json | 76 +++++++++++++++
>> qapi/meson.build | 1 +
>> qapi/qapi-schema.json | 1 +
>> qemu-options.hx | 39 +++++++-
>> softmmu/globals.c | 2 +
>> softmmu/memory.c | 48 ++++++++++
>> softmmu/physmem.c | 49 ++++++++--
>> softmmu/runstate.c | 49 +++++++++-
>> softmmu/vl.c | 21 ++++-
>> stubs/cpr.c | 3 +
>> stubs/meson.build | 1 +
>> trace-events | 1 +
>> util/env.c | 99 +++++++++++++++++++
>> util/meson.build | 1 +
>> util/oslib-posix.c | 9 ++
>> util/oslib-win32.c | 4 +
>> util/qemu-config.c | 4 +
>> 62 files changed, 1431 insertions(+), 74 deletions(-)
>> create mode 100644 hw/vfio/cpr.c
>> create mode 100644 include/migration/cpr.h
>> create mode 100644 include/qemu/env.h
>> create mode 100644 migration/cpr.c
>> create mode 100644 qapi/cpr.json
>> create mode 100644 stubs/cpr.c
>> create mode 100644 util/env.c
>>
prev parent reply other threads:[~2021-06-02 15:21 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-07 12:24 [PATCH V3 00/22] Live Update Steve Sistare
2021-05-07 12:24 ` [PATCH V3 01/22] as_flat_walk Steve Sistare
2021-05-07 12:25 ` [PATCH V3 02/22] qemu_ram_volatile Steve Sistare
2021-05-07 12:25 ` [PATCH V3 03/22] oslib: qemu_clr_cloexec Steve Sistare
2021-05-07 12:25 ` [PATCH V3 04/22] util: env var helpers Steve Sistare
2021-05-07 12:25 ` [PATCH V3 05/22] machine: memfd-alloc option Steve Sistare
2021-05-07 12:25 ` [PATCH V3 06/22] vl: add helper to request re-exec Steve Sistare
2021-05-07 14:31 ` Eric Blake
2021-05-13 20:19 ` Steven Sistare
2021-05-14 8:18 ` Daniel P. Berrangé
2021-05-12 16:27 ` Stefan Hajnoczi
2021-05-13 20:20 ` Steven Sistare
2021-05-07 12:25 ` [PATCH V3 07/22] cpr Steve Sistare
2021-05-12 16:19 ` Stefan Hajnoczi
2021-05-13 20:21 ` Steven Sistare
2021-05-14 11:28 ` Stefan Hajnoczi
2021-05-14 15:14 ` Steven Sistare
2021-05-18 13:42 ` Stefan Hajnoczi
2021-05-07 12:25 ` [PATCH V3 08/22] cpr: QMP interfaces Steve Sistare
2021-06-04 13:59 ` Eric Blake
2021-06-07 17:19 ` Steven Sistare
2021-05-07 12:25 ` [PATCH V3 09/22] cpr: HMP interfaces Steve Sistare
2021-05-07 12:25 ` [PATCH V3 10/22] pci: export functions for cpr Steve Sistare
2021-05-07 12:25 ` [PATCH V3 11/22] vfio-pci: refactor " Steve Sistare
2021-05-19 22:38 ` Alex Williamson
2021-05-21 13:33 ` Steven Sistare
2021-05-21 21:07 ` Alex Williamson
2021-05-21 21:18 ` Steven Sistare
2021-05-07 12:25 ` [PATCH V3 12/22] vfio-pci: cpr part 1 Steve Sistare
2021-05-21 22:24 ` Alex Williamson
2021-05-24 18:29 ` Steven Sistare
2021-06-11 18:15 ` Steven Sistare
2021-06-11 19:43 ` Steven Sistare
2021-05-07 12:25 ` [PATCH V3 13/22] vfio-pci: cpr part 2 Steve Sistare
2021-05-21 22:24 ` Alex Williamson
2021-05-24 18:31 ` Steven Sistare
2021-05-07 12:25 ` [PATCH V3 14/22] vhost: reset vhost devices upon cprsave Steve Sistare
2021-05-07 12:25 ` [PATCH V3 15/22] hostmem-memfd: cpr support Steve Sistare
2021-05-07 12:25 ` [PATCH V3 16/22] chardev: cpr framework Steve Sistare
2021-05-07 14:33 ` Eric Blake
2021-05-13 20:19 ` Steven Sistare
2021-05-07 12:25 ` [PATCH V3 17/22] chardev: cpr for simple devices Steve Sistare
2021-05-07 12:25 ` [PATCH V3 18/22] chardev: cpr for pty Steve Sistare
2021-05-07 12:25 ` [PATCH V3 19/22] chardev: cpr for sockets Steve Sistare
2021-05-07 12:25 ` [PATCH V3 20/22] cpr: only-cpr-capable option Steve Sistare
2021-05-07 12:25 ` [PATCH V3 21/22] cpr: maintainers Steve Sistare
2021-05-07 12:25 ` [PATCH V3 22/22] simplify savevm Steve Sistare
2021-05-07 13:00 ` [PATCH V3 00/22] Live Update no-reply
2021-05-13 20:42 ` Steven Sistare
2021-05-12 16:42 ` Stefan Hajnoczi
2021-05-13 20:21 ` Steven Sistare
2021-05-14 11:53 ` Stefan Hajnoczi
2021-05-14 15:15 ` Steven Sistare
2021-05-17 11:40 ` Stefan Hajnoczi
2021-05-17 19:10 ` Alex Williamson
2021-05-18 13:39 ` Stefan Hajnoczi
2021-05-18 15:48 ` Steven Sistare
2021-05-18 9:57 ` Dr. David Alan Gilbert
2021-05-18 16:00 ` Steven Sistare
2021-05-18 19:23 ` Dr. David Alan Gilbert
2021-05-18 20:01 ` Alex Williamson
2021-05-18 20:14 ` Steven Sistare
2021-05-20 13:00 ` [PATCH V3 00/22] Live Update [reboot] Dr. David Alan Gilbert
2021-05-21 14:55 ` Steven Sistare
2021-06-15 19:14 ` Dr. David Alan Gilbert
2021-06-24 15:05 ` Steven Sistare
2021-07-06 17:31 ` Steven Sistare
2021-05-20 13:13 ` [PATCH V3 00/22] Live Update [restart] Dr. David Alan Gilbert
2021-05-21 14:56 ` Steven Sistare
2021-05-24 10:39 ` Dr. David Alan Gilbert
2021-06-02 13:51 ` Steven Sistare
2021-06-03 19:36 ` Dr. David Alan Gilbert
2021-06-03 20:44 ` Daniel P. Berrangé
2021-06-07 16:40 ` [PATCH V3 00/22] Live Update [restart] : exec Steven Sistare
2021-06-14 14:31 ` Steven Sistare
2021-06-14 14:36 ` Daniel P. Berrangé
2021-06-15 19:05 ` Dr. David Alan Gilbert
2021-06-07 18:08 ` [PATCH V3 00/22] Live Update [restart] : code replication Steven Sistare
2021-06-14 14:33 ` Steven Sistare
2021-05-19 16:43 ` [PATCH V3 00/22] Live Update Steven Sistare
2021-06-02 15:19 ` Steven Sistare [this message]
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