When an always-on migration capability is supposed to be enabled on both
sides of migration, each side can only enable the feature if it is
enabled by the other side.

Thus the source host sends a list of supported migration capabilities in
the migration cookie generated in the Begin phase. The destination host
consumes the list in the Prepare phase and decides what capabilities can
be enabled when starting a QEMU process for incoming migration. Once
done the destination sends the list of supported capabilities back to
the source where it is used during the Perform phase to determine what
capabilities can be automatically enabled.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Some migration capabilities may be enabled automatically, but only if
both sides of migration support them. Thus we need to be able transfer
the list of supported migration capabilities in migration cookie.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Since the monitor code no longer needs to see this enum, we move it
to the place where migration parameters are defined and drop the
"monitor" reference from the name.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

We want to have all migration capabilities parsing and formatting at one
place, i.e., in qemu_migration_params.c. The parsing is already there in
qemuMigrationCapsCheck.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Adding support for new migration parameter requires a lot of places to
be changed (most likely by copy&paste engineering): new variables to
store the parameter value and the associated *_set bool, JSON formatter
and parser, XML formatter and parser (to be added soon), and the actual
code to set the parameter. It's pretty easy to forget about some of the
places which need to be updated and end up with incorrect support. The
goal of this patch is to let most of the places do their job without any
modifications when new parameters are added.

To achieve the goal, a new qemuMigrationParam enum is introduced and all
parameters are stored in an array indexed by the items of this enum.
This will also allow us to automatically set the migration parameters
which directly correspond to libvirt's typed parameters accepted by
virDomainMigrate* APIs.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

It's no longer used by the monitor code so we can hide it inside
qemu_migration_params.c.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

We want to have all migration parameters parsing and formatting at one
place, i.e., in qemu_migration_params.c.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

We want to have all migration parameters parsing and formatting at once
place, i.e., in qemu_migration_params.c.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

The test is mostly useless and we want to refactor migration parameters
even further. The refactoring will allow us to introduce enhanced tests
for migration parameters.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Use this internal structure only in qemu_migration_params.c and change
other non-test users to use the high level qemuMigrationParams struct.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Let's separate the code which queries QEMU for migration parameters from
qemuMigrationParamsCheck into a dedicated function.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

By merging qemuMigrationAnyCompressionParse into
qemuMigrationParamsSetCompression we can drop the useless intermediate
qemuMigrationCompression structure and parse compression related typed
parameters and flags directly into qemuMigrationParams.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Since every parameter or capability set in qemuMigrationCompression
structure is now reflected in qemuMigrationParams structure, we can
replace qemuMigrationAnyCompressionDump with a new API which will work
on qemuMigrationParams.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

There's no need to call this API explicitly in the migration code. We
can pass the compression parameters to qemuMigrationParamsFromFlags and
it can internally call qemuMigrationParamsSetCompression to apply them
to the qemuMigrationParams structure.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

The code really belongs to qemu_migration_params.c.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

The API will soon be called from qemuMigrationParamsFromFlags. Let's
move it to avoid the need to add a forward declaration.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

It's become only a tiny wrapper around virBitmapSetBit, which can easily
be called directly. We don't need to call virBitmapClearBit since
migParams->caps bitmap is initialized with zeros.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

So far it's used only for CPU throttling parameters which are all ints,
but we'll soon want to use it for more parameters with different types.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Propagate the calls up the stack to the point where
qemuMigrationParamsFromFlags is called. The end goal achieved in the
following few patches is to merge compression parameters into the
general migration parameters code.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Most migration capabilities are directly connected with
virDomainMigrateFlags so qemuMigrationParamsFromFlags can automatically
enable them.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Some migration capabilities are always enabled if QEMU supports them. We
can just drop the explicit code for them and let
qemuMigrationParamsCheck automatically set such capabilities.

QEMU_MONITOR_MIGRATION_CAPS_EVENTS would normally be one of the always
on features, but it is the only feature we want to enable even for other
jobs which internally use migration (such as save and snapshot). Hence
this capability is set very early after libvirtd connects to QEMU
monitor.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

It's just a tiny wrapper around qemuMigrationParamsSetCapability and
setting priv->job.postcopyEnabled is not something qemuMigrationParams
code should be doing anyway so let the callers do it.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

It is no longer used outside qemu_migration_params.c.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Every migration entry point in qemu_driver is supposed to call
qemuMigrationParamsFromFlags to transform flags and parameters into
qemuMigrationParams structure and pass the result to qemuMigration*
APIs.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Some migration parameters and capabilities are supposed to be set on
both sides of migration while others should only be set on one side. For
example, CPU throttling parameters make no sense on the destination and
they can be used even if the destination is too old to support them.

To make qemuMigrationParamsFromFlags more general and usable on both
sides of migration, we need to tell it what side it's been called on.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Instead of checking each capability at the time we want to set it in
qemuMigrationParamsSetCapability we can check all of them at once in
qemuMigrationParamsCheck.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

We reached the point when qemuMigrationParamsApply is the only API which
sends migration parameters and capabilities to QEMU. Thus all but the
TLS parameters can be set before we ask QEMU for the current values of
all parameters in qemuMigrationParamsCheck.

Supported migration capabilities are queried as soon as libvirt connects
to QEMU monitor so we can check them anytime.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

We reached the point when qemuMigrationParamsApply is the only API which
sends migration parameters and capabilities to QEMU. Thus all but the
TLS parameters can be set before we ask QEMU for the current values of
all parameters in qemuMigrationParamsCheck.

Supported migration capabilities are queried as soon as libvirt connects
to QEMU monitor so we can check them anytime.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Prefer xbzrle-cache-size migration parameter over the special
migrate-set-cache-size QMP command.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Originally QEMU provided query-migrate-cache-size and
migrate-set-cache-size QMP commands for querying/setting XBZRLE cache
size. In version 2.11 QEMU added support for XBZRLE cache size to the
general migration paramaters commands.

This patch adds support for this parameter to libvirt to make sure it is
properly restored to its original value after a failed or aborted
migration.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Rework all remaining callers of qemuMonitorSetMigrationCapability to use
the new qemuMonitorSetMigrationCapabilities API.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Migration capabilities are closely related to migration parameters and
it makes sense to keep them in a single data structure. Similarly to
migration parameters the capabilities are all send to QEMU at once in
qemuMigrationParamsApply, all other APIs operate on the
qemuMigrationParams structure.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Our current monitor API forces the caller to call
migrate-set-capabilities QMP command for each capability separately,
which is quite suboptimal. Let's add a new API for setting all
capabilities at once.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

All users of migration parameters are supposed to use APIs provided by
qemu_migration_params.c without having to worry about the internals.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

The new name is qemuMigrationParamsApply and it will soon become the
only API which will send all requested migration parameters and
capabilities to QEMU. All other qemuMigrationParams* APIs will just
operate on the qemuMigrationParams structure.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

There's no real reason for qemuMigrationParamsEnableTLS to require the
callers to pass a valid virQEMUDriverConfigPtr, it can just call
virQEMUDriverGetConfig.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>