The qemu coding standard is to use CamelCase for type and structure names,
and the pseries code follows that... sort of. There are quite a lot of
places where we bend the rules in order to preserve the capitalization of
internal acronyms like "PHB", "TCE", "DIMM" and most commonly "sPAPR".
That was a bad idea - it frequently leads to names ending up with hard to
read clusters of capital letters, and means they don't catch the eye as
type identifiers, which is kind of the point of the CamelCase convention in
the first place.
In short, keeping type identifiers look like CamelCase is more important
than preserving standard capitalization of internal "words". So, this
patch renames a heap of spapr internal type names to a more standard
CamelCase.
In addition to case changes, we also make some other identifier renames:
VIOsPAPR* -> SpaprVio*
The reverse word ordering was only ever used to mitigate the capital
cluster, so revert to the natural ordering.
VIOsPAPRVTYDevice -> SpaprVioVty
VIOsPAPRVLANDevice -> SpaprVioVlan
Brevity, since the "Device" didn't add useful information
sPAPRDRConnector -> SpaprDrc
sPAPRDRConnectorClass -> SpaprDrcClass
Brevity, and makes it clearer this is the same thing as a "DRC"
mentioned in many other places in the code
This is 100% a mechanical search-and-replace patch. It will, however,
conflict with essentially any and all outstanding patches touching the
spapr code.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The POWER9 processor does not support per-core frequency control. The
cores are arranged in groups of four, along with their respective L2
and L3 caches, into a structure known as a Quad. The frequency must be
managed at the Quad level.
Provide a basic Quad model to fake the settings done by the firmware
on the Non-Cacheable Unit (NCU). Each core pair (EX) needs a special
BAR setting for the TIMA area of XIVE because it resides on the same
address on all chips.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190307223548.20516-12-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Provide a new class attribute to define XSCOM operations per CPU
family and add a couple of XSCOM addresses controlling the power
management states of the core on POWER9.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190307223548.20516-11-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The LPC Controller on POWER9 is very similar to the one found on
POWER8 but accesses are now done via on MMIOs, without the XSCOM and
ECCB logic. The device tree is populated differently so we add a
specific POWER9 routine for the purpose.
SerIRQ routing is yet to be done.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190307223548.20516-7-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The ISA bus has a different DT nodename on POWER9. Compute the name
when the PnvChip is realized, that is before it is used by the machine
to populate the device tree with the ISA devices.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190307223548.20516-6-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The PSI bridge on POWER9 is very similar to POWER8. The BAR is still
set through XSCOM but the controls are now entirely done with MMIOs.
More interrupts are defined and the interrupt controller interface has
changed to XIVE. The POWER9 model is a first example of the usage of
the notify() handler of the XiveNotifier interface, linking the PSI
XiveSource to its owning device model.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190307223548.20516-3-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
To ease the introduction of the PSI bridge model for POWER9, abstract
the POWER chip differences in a PnvPsi class model and introduce a
specific Pnv8Psi type for POWER8. POWER8 interface to the interrupt
controller is still XICS whereas POWER9 uses the new XIVE model.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190307223548.20516-2-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
On sPAPR vfio_listener_region_add() is called in 2 situations:
1. a new listener is registered from vfio_connect_container();
2. a new IOMMU Memory Region is added from rtas_ibm_create_pe_dma_window().
In both cases vfio_listener_region_add() calls
memory_region_iommu_replay() to notify newly registered IOMMU notifiers
about existing mappings which is totally desirable for case 1.
However for case 2 it is nothing but noop as the window has just been
created and has no valid mappings so replaying those does not do anything.
It is barely noticeable with usual guests but if the window happens to be
really big, such no-op replay might take minutes and trigger RCU stall
warnings in the guest.
For example, a upcoming GPU RAM memory region mapped at 64TiB (right
after SPAPR_PCI_LIMIT) causes a 64bit DMA window to be at least 128TiB
which is (128<<40)/0x10000=2.147.483.648 TCEs to replay.
This mitigates the problem by adding an "skipping_replay" flag to
sPAPRTCETable and defining sPAPR own IOMMU MR replay() hook which does
exactly the same thing as the generic one except it returns early if
@skipping_replay==true.
Another way of fixing this would be delaying replay till the very first
H_PUT_TCE but this does not work if in-kernel H_PUT_TCE handler is
enabled (a likely case).
When "ibm,create-pe-dma-window" is complete, the guest will map only
required regions of the huge DMA window.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Message-Id: <20190307050518.64968-2-aik@ozlabs.ru>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The POWER9 and POWER8 processors have different interrupt controllers,
and reporting their state requires calling different helper routines.
However, the interrupt presenters are still handled in the higher
level pic_print_info() routine because they are not related to the
chip.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190306085032.15744-9-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This is a simple model of the POWER9 XIVE interrupt controller for the
PowerNV machine which only addresses the needs of the skiboot
firmware. The PowerNV model reuses the common XIVE framework developed
for sPAPR as the fundamentals aspects are quite the same. The
difference are outlined below.
The controller initial BAR configuration is performed using the XSCOM
bus from there, MMIO are used for further configuration.
The MMIO regions exposed are :
- Interrupt controller registers
- ESB pages for IPIs and ENDs
- Presenter MMIO (Not used)
- Thread Interrupt Management Area MMIO, direct and indirect
The virtualization controller MMIO region containing the IPI ESB pages
and END ESB pages is sub-divided into "sets" which map portions of the
VC region to the different ESB pages. These are modeled with custom
address spaces and the XiveSource and XiveENDSource objects are sized
to the maximum allowed by HW. The memory regions are resized at
run-time using the configuration of EDT set translation table provided
by the firmware.
The XIVE virtualization structure tables (EAT, ENDT, NVTT) are now in
the machine RAM and not in the hypervisor anymore. The firmware
(skiboot) configures these tables using Virtual Structure Descriptor
defining the characteristics of each table : SBE, EAS, END and
NVT. These are later used to access the virtual interrupt entries. The
internal cache of these tables in the interrupt controller is updated
and invalidated using a set of registers.
Still to address to complete the model but not fully required is the
support for block grouping. Escalation support will be necessary for
KVM guests.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190306085032.15744-7-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The PowerNV machine with need to encode the block id in the source
interrupt number before forwarding the source event notification to
the Router.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190306085032.15744-5-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The PowerNV machine can perform indirect loads and stores on the TIMA
on behalf of another CPU. Give the controller the possibility to call
the TIMA memory accessors with a XiveTCTX of its choice.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190306085032.15744-4-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
SPAPR_MEMORY_BLOCK_SIZE is logically a difference in memory addresses, and
hence of type hwaddr which is 64-bit. Previously it wasn't marked as such
which means that it could be treated as 32-bit. That will work in some
circumstances but if multiplied by another 32-bit value it could lead to
a 32-bit overflow and an incorrect result.
One specific instance of this in spapr_lmb_dt_populate() was spotted by
Coverity (CID 1399145).
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Introduce a new spapr_cap SPAPR_CAP_CCF_ASSIST to be used to indicate
the requirement for a hw-assisted version of the count cache flush
workaround.
The count cache flush workaround is a software workaround which can be
used to flush the count cache on context switch. Some revisions of
hardware may have a hardware accelerated flush, in which case the
software flush can be shortened. This cap is used to set the
availability of such hardware acceleration for the count cache flush
routine.
The availability of such hardware acceleration is indicated by the
H_CPU_CHAR_BCCTR_FLUSH_ASSIST flag being set in the characteristics
returned from the KVM_PPC_GET_CPU_CHAR ioctl.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Message-Id: <20190301031912.28809-2-sjitindarsingh@gmail.com>
[dwg: Small style fixes]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The spapr_cap SPAPR_CAP_IBS is used to indicate the level of capability
for mitigations for indirect branch speculation. Currently the available
values are broken (default), fixed-ibs (fixed by serialising indirect
branches) and fixed-ccd (fixed by diabling the count cache).
Introduce a new value for this capability denoted workaround, meaning that
software can work around the issue by flushing the count cache on
context switch. This option is available if the hypervisor sets the
H_CPU_BEHAV_FLUSH_COUNT_CACHE flag in the cpu behaviours returned from
the KVM_PPC_GET_CPU_CHAR ioctl.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Message-Id: <20190301031912.28809-1-sjitindarsingh@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Block layer patches:
- qcow2: Support for external data files
- qcow2: Default to 4KB for the qcow2 cache entry size
- Apply block driver whitelist for -drive format=help
- Several qemu-iotests improvements
# gpg: Signature made Fri 08 Mar 2019 12:54:27 GMT
# gpg: using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6
* remotes/kevin/tags/for-upstream: (33 commits)
qcow2 spec: Describe string header extensions
qemu-iotests: Add dependency to qemu-nbd tool
ahci-test: Add dependency to qemu-img tool
qemu-iotests: amend with external data file
qemu-iotests: General tests for qcow2 with external data file
qemu-iotests: Preallocation with external data file
qcow2: Implement data-file-raw create option
qcow2: Store data file name in the image
qcow2: Creating images with external data file
qcow2: Add basic data-file infrastructure
qcow2: Support external data file in qemu-img check
qcow2: Return error for snapshot operation with data file
qcow2: External file I/O
qcow2: Prepare qcow2_co_block_status() for data file
qcow2: Return 0/-errno in qcow2_alloc_compressed_cluster_offset()
qcow2: Don't assume 0 is an invalid cluster offset
qcow2: Prepare count_contiguous_clusters() for external data file
qcow2: Prepare qcow2_get_cluster_type() for external data file
qcow2: Pass bs to qcow2_get_cluster_type()
qcow2: Basic definitions for external data files
...
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Provide an option to force QEMU to always keep the external data file
consistent as a standalone read-only raw image.
At the moment, this means making sure that write_zeroes requests are
forwarded to the data file instead of just updating the metadata, and
checking that no backing file is used.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
bdrv_iterate_format (which is currently only used for printing out the
formats supported by the block layer) doesn't take format whitelisting
into account.
This creates a problem for tests: they enumerate supported formats to
decide which tests to enable, but then discover that QEMU doesn't let
them actually use some of those formats.
To avoid that, exclude formats that are not whitelisted from
enumeration, if whitelisting is in use. Since we have separate
whitelists for r/w and r/o, take this a parameter to
bdrv_iterate_format, and print two lists of supported formats (r/w and
r/o) in main qemu.
Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In existing code we create the gcontext dynamically at the first
access of the gcontext from caller. That can bring some complexity
and potential races during using iothread. Since the context itself
is not that big a resource, and we won't have millions of iothread,
let's simply create the gcontext unconditionally.
This will also be a preparation work further to move the thread
context push operation earlier than before (now it's only pushed right
before we want to start running the gmainloop).
Removing the g_once since it's not necessary, while introducing a new
run_gcontext boolean to show whether we want to run the gcontext.
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-id: 20190306115532.23025-3-peterx@redhat.com
Message-Id: <20190306115532.23025-3-peterx@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Add qgraph API that allows to add/remove nodes and edges from the graph,
implementation of Depth First Search to discover the paths and basic unit
test to check correctness of the API.
Included also a main executable that takes care of starting the framework,
create the nodes, set the available drivers/machines, discover the path and
run tests.
graph.h provides the public API to manage the graph nodes/edges
graph_extra.h provides a more private API used successively by the gtest integration part
qos-test.c provides the main executable
Signed-off-by: Emanuele Giuseppe Esposito <e.emanuelegiuseppe@gmail.com>
[Paolo's changes compared to the Google Summer of Code submission:
* added subprocess to test options
* refactored object creation to support live migration tests
* removed driver .before callback (unused)
* removed test .after callbacks (replaced by GTest destruction queue)]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
slirp migration code uses QEMU vmstate so far, when building WITH_QEMU.
Introduce slirp_state_{load,save,version}() functions to move the
state saving handling to libslirp side.
So far, the bitstream compatibility should remain equal with current
QEMU, as this is effectively using the same code, with the same format
etc. When libslirp is made standalone, we will need some mechanism to
ensure bitstream compatibility regardless of the libslirp version
installed. See the FIXME note in the code.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20190212162524.31504-3-marcandre.lureau@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
As with the previous patch to qemu-nbd, the nbd-server-start QMP command
also needs to be able to specify authorization when enabling TLS encryption.
First the client must create a QAuthZ object instance using the
'object-add' command:
{
'execute': 'object-add',
'arguments': {
'qom-type': 'authz-list',
'id': 'authz0',
'parameters': {
'policy': 'deny',
'rules': [
{
'match': '*CN=fred',
'policy': 'allow'
}
]
}
}
}
They can then reference this in the new 'tls-authz' parameter when
executing the 'nbd-server-start' command:
{
'execute': 'nbd-server-start',
'arguments': {
'addr': {
'type': 'inet',
'host': '127.0.0.1',
'port': '9000'
},
'tls-creds': 'tls0',
'tls-authz': 'authz0'
}
}
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <20190227162035.18543-3-berrange@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Currently any client which can complete the TLS handshake is able to use
the NBD server. The server admin can turn on the 'verify-peer' option
for the x509 creds to require the client to provide a x509 certificate.
This means the client will have to acquire a certificate from the CA
before they are permitted to use the NBD server. This is still a fairly
low bar to cross.
This adds a '--tls-authz OBJECT-ID' option to the qemu-nbd command which
takes the ID of a previously added 'QAuthZ' object instance. This will
be used to validate the client's x509 distinguished name. Clients
failing the authorization check will not be permitted to use the NBD
server.
For example to setup authorization that only allows connection from a client
whose x509 certificate distinguished name is
CN=laptop.example.com,O=Example Org,L=London,ST=London,C=GB
escape the commas in the name and use:
qemu-nbd --object tls-creds-x509,id=tls0,dir=/home/berrange/qemutls,\
endpoint=server,verify-peer=yes \
--object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,\
O=Example Org,,L=London,,ST=London,,C=GB' \
--tls-creds tls0 \
--tls-authz authz0 \
....other qemu-nbd args...
NB: a real shell command line would not have leading whitespace after
the line continuation, it is just included here for clarity.
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <20190227162035.18543-2-berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: split long line in --help text, tweak 233 to show that whitespace
after ,, in identity= portion is actually okay]
Signed-off-by: Eric Blake <eblake@redhat.com>
Let's use a wrapper instead of looking it up manually. This function can
than be reused when we explicitly want to have the bus hotplug handler
(e.g. when the bus hotplug handler was overwritten by the machine
hotplug handler).
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190228122849.4296-4-david@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
it will allow to return another hotplug handler than the default
one for a specific bus based device type. Which is needed to handle
non trivial plug/unplug sequences that need the access to resources
configured outside of bus where device is attached.
That will allow for returned hotplug handler to orchestrate wiring
in arbitrary order, by chaining other hotplug handlers when
it's needed.
PS:
It could be used for hybrid virtio-mem and virtio-pmem devices
where it will return machine as hotplug handler which will do
necessary wiring at machine level and then pass control down
the chain to bus specific hotplug handler.
Example of top level hotplug handler override and custom plug sequence:
some_machine_get_hotplug_handler(machine){
if (object_dynamic_cast(OBJECT(dev), TYPE_SOME_BUS_DEVICE)) {
return HOTPLUG_HANDLER(machine);
}
return NULL;
}
some_machine_device_plug(hotplug_dev, dev) {
if (object_dynamic_cast(OBJECT(dev), TYPE_SOME_BUS_DEVICE)) {
/* do machine specific initialization */
some_machine_init_special_device(dev)
/* pass control to bus specific handler */
hotplug_handler_plug(dev->parent_bus->hotplug_handler, dev)
}
}
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190228122849.4296-3-david@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
The qbus_is_full(BusState *bus) function (qdev_monitor.c) compares the max_index
value of the BusState structure with the max_dev value of the BusClass structure
to determine whether the maximum number of children has been reached for the
bus. The problem is, the max_index field of the BusState structure does not
necessarily reflect the number of devices that have been plugged into
the bus.
Whenever a child device is plugged into the bus, the bus's max_index value is
assigned to the child device and then incremented. If the child is subsequently
unplugged, the value of the max_index does not change and no longer reflects the
number of children.
When the bus's max_index value reaches the maximum number of devices
allowed for the bus (i.e., the max_dev field in the BusClass structure),
attempts to plug another device will be rejected claiming that the bus is
full -- even if the bus is actually empty.
To resolve the problem, a new 'num_children' field is being added to the
BusState structure to keep track of the number of children plugged into the
bus. It will be incremented when a child is plugged, and decremented when a
child is unplugged.
Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Pierre Morel<pmorel@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Message-Id: <1545062250-7573-1-git-send-email-akrowiak@linux.ibm.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Migation pull 2019-03-06
(This replaces the pull sent yesterday)
a) 4 small fixes including the cancel problem
that caused the ahci migration test to fail
intermittently
b) Yury's ignore-shared feature
c) Juan's extra tests
d) Wei Wang's free page hinting
e) Some Colo fixes from Zhang Chen
Diff from yesterdays pull:
1) A missing fix of mine (cleanup during exit)
2) Changes from Eric/Markus on 'Create socket-address parameter'
# gpg: Signature made Wed 06 Mar 2019 11:39:53 GMT
# gpg: using RSA key 0516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>" [full]
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A 9FA9 0516 331E BC5B FDE7
* remotes/dgilbert/tags/pull-migration-20190306a: (22 commits)
qapi/migration.json: Remove a variable that doesn't exist in example
Migration/colo.c: Make COLO node running after failover
Migration/colo.c: Fix double close bug when occur COLO failover
virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT
migration/ram.c: add the free page optimization enable flag
migration/ram.c: add a notifier chain for precopy
migration: API to clear bits of guest free pages from the dirty bitmap
migration: use bitmap_mutex in migration_bitmap_clear_dirty
bitmap: bitmap_count_one_with_offset
bitmap: fix bitmap_count_one
tests: Add basic migration precopy tcp test
migration: Create socket-address parameter
tests: Add migration xbzrle test
migration: Add capabilities validation
tests/migration-test: Add a test for ignore-shared capability
migration: Add an ability to ignore shared RAM blocks
migration: Introduce ignore-shared capability
exec: Change RAMBlockIterFunc definition
migration/rdma: clang compilation fix
migration: Cleanup during exit
...
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The new feature enables the virtio-balloon device to receive hints of
guest free pages from the free page vq.
A notifier is registered to the migration precopy notifier chain. The
notifier calls free_page_start after the migration thread syncs the dirty
bitmap, so that the free page optimization starts to clear bits of free
pages from the bitmap. It calls the free_page_stop before the migration
thread syncs the bitmap, which is the end of the current round of ram
save. The free_page_stop is also called to stop the optimization in the
case when there is an error occurred in the process of ram saving.
Note: balloon will report pages which were free at the time of this call.
As the reporting happens asynchronously, dirty bit logging must be
enabled before this free_page_start call is made. Guest reporting must be
disabled before the migration dirty bitmap is synchronized.
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
CC: Michael S. Tsirkin <mst@redhat.com>
CC: Dr. David Alan Gilbert <dgilbert@redhat.com>
CC: Juan Quintela <quintela@redhat.com>
CC: Peter Xu <peterx@redhat.com>
Message-Id: <1544516693-5395-8-git-send-email-wei.w.wang@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
dgilbert: Dropped kernel header update, fixed up CMD_ID_* name change
This patch adds the free page optimization enable flag, and a function
to set this flag. When the free page optimization is enabled, not all
the pages are needed to be sent in the bulk stage.
Why using a new flag, instead of directly disabling ram_bulk_stage when
the optimization is running?
Thanks for Peter Xu's reminder that disabling ram_bulk_stage will affect
the use of compression. Please see save_page_use_compression. When
xbzrle and compression are used, if free page optimizaion causes the
ram_bulk_stage to be disabled, save_page_use_compression will return
false, which disables the use of compression. That is, if free page
optimization avoids the sending of half of the guest pages, the other
half of pages loses the benefits of compression in the meantime. Using a
new flag to let migration_bitmap_find_dirty skip the free pages in the
bulk stage will avoid the above issue.
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
CC: Dr. David Alan Gilbert <dgilbert@redhat.com>
CC: Juan Quintela <quintela@redhat.com>
CC: Michael S. Tsirkin <mst@redhat.com>
CC: Peter Xu <peterx@redhat.com>
Message-Id: <1544516693-5395-7-git-send-email-wei.w.wang@intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Alexey Kardashevskiy