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Tsirkin" , Thomas Huth , Jason Wang , Alex Williamson , Peter Xu , Steve Sistare Subject: [PULL 21/25] migration: update cpr-reboot description Date: Wed, 28 Feb 2024 13:13:11 +0800 Message-ID: <20240228051315.400759-22-peterx@redhat.com> In-Reply-To: <20240228051315.400759-1-peterx@redhat.com> References: <20240228051315.400759-1-peterx@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.129.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.088, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Steve Sistare Clarify qapi for cpr-reboot migration mode, and add vfio support. Signed-off-by: Steve Sistare Reviewed-by: Peter Xu Link: https://lore.kernel.org/r/1708622920-68779-14-git-send-email-steven.sistare@oracle.com Signed-off-by: Peter Xu --- qapi/migration.json | 35 ++++++++++++++++++++++------------- 1 file 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' ] }