Commit Graph

545 Commits

Author SHA1 Message Date
Peter Krempa
9693b06630 qemu: domain: Move and unexport 'qemuDomainStorageIdNew/Reset'
They're used only inside qemu_domain.c. Move it before their usage,
and unexport them.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-02-14 13:13:59 +01:00
Peter Krempa
f0a4951616 qemu: domain: Store 'qomPath' in qemuDomainVcpuPrivate
The QOM path will be needed by code which is querying the cpu flags via
'qom-get' and thus needs a valid QOM path to the vCPU.

Add it into the private data and transfer from the queried data.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-02-07 18:04:52 +01:00
Lubomir Rintel
fc80b94a57 qemu: add qemuDomainIsMipsMalta()
This identifies various MIPS Malta machines, be it 32-bit or 64-bit,
little-endian or big-endian.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2022-02-02 10:07:19 +01:00
Tim Wiederhake
fdec0cbf43 Fix some typos
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2021-12-15 11:52:54 +01:00
Jiri Denemark
7ab39cf04b qemu: Drop driver parameter from qemuDomainSetFakeReboot
And its callers. The parameter is no longer used since virDomainObjSave
was replaced with qemuDomainSaveStatus wrapper.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2021-12-15 10:44:50 +01:00
Peter Krempa
7b94408db5 qemu: Store TLS config options for chardevs in qemuDomainChrSourcePrivate
When setting up TLS options from config in qemuDomainPrepareChardevSourceOne
we can also extract the x509 certificate path and default tlsVerify
setting so that 'qemuBuildChardevCommand' doesn't need to access the
config object any more.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-12-10 16:37:42 +01:00
Peter Krempa
1ea28569a0 qemuBuildChardevCommand: Split creation of the command and setup of other objects
Completely seprate the creation of the commandline string from the setup
of other objects instantiated on the commandline.

'qemuBuildChardevCommand' will aggregate the setup of individual
parameters such as -add-fd and setup of TLS and the -chardev parameter
itself while the code formatting the commandline will be moved into
qemuBuildChardevStr.

'fdset' names are then stored in qemuDomainChrSourcePrivate.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-12-10 16:37:42 +01:00
Peter Krempa
5b7a777bc8 qemu: Store chardev 'wait' flag in chardev source private data
We have just one case when we wish to wait for incomming connections for
a listening socket and that is for vhost-user network devices.

Passing this via a flag to qemuBuildChrChardevStr is unwieldy. Add a
field to qemuDomainChrSourcePrivate and populate it for our special
case inside of qemuDomainPrepareChardevSourceOne.

Since we wait for incomming connections only on startup of a new VM we
also need to pass in a flag whether qemuDomainPrepareChardevSourceOne
is called on a new start or on hotplug.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-12-10 16:37:42 +01:00
Peter Krempa
73871c3a30 qemu: domain: Refactor chardev definition preparing
Use the qemuDomainDeviceBackendChardevForeach helper to iterate all
eligible structs and convert the setup of the TLS defaults from the
config.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-12-10 16:37:42 +01:00
Peter Krempa
ff024b60cc qemu: Move creation and opening of chardev backend FDs to host prepare step
The opening of files for FD passing for a chardev backend was
historically done in the function which is formatting the commandline.

This has multiple problems. Firstly the function takes a lot of
parameters which need to be passed through the commandline formatters.
This made the 'qemuBuildChrChardevStr' extremely unappealing to the
extent that we have multiple other custom formatters in places which
didn't really want to use the function.

Additionally the function is also creating files in the host in certain
configurations which is wrong for a commandline formatter to do. This
meant that e.g. not all chardev test cases can be converted to use
DO_TEST_CAPS_LATEST as we attempt to use such code path and attempt to
create files outside of the test directory.

This patch moves the opening of the filedescriptors from
'qemuBuildChrChardevFileStr' into a new helper
'qemuProcessPrepareHostBackendChardevOne' which is called using
'qemuDomainDeviceBackendChardevForeach'.

To preserve test behaviour we also have another instance
'testPrepareHostBackendChardevOne' which is populating mock
filedescriptors.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-12-10 16:37:42 +01:00
Peter Krempa
728f0079ea qemu: domain: Introduce helpers for initializing chardev backend of devices
Introduce qemuDomainDeviceBackendChardevForeach(One) which calls the
callback if either given device has a chardev backend or for all chardev
backends of all devices.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-12-10 16:37:42 +01:00
Kristina Hanicova
01f9873724 qemu_domainjob: move jobs_queued to struct qemuDomainJobObj
I think it makes more sense for the variable about jobs to be in
the job object. I also renamed it to be consistent with the rest
of the struct.

Signed-off-by: Kristina Hanicova <khanicov@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>
2021-12-01 12:45:40 +01:00
Ján Tomko
f1ea5bd506 qemu: turn qemuDomainObjExitMonitor into void
This reverts my
    commit dc2fd51fd7
    Check for domain liveness in qemuDomainObjExitMonitor
which fixed the symptoms of the bug later fixed by
    commit 81f50cb92d
    qemu: Avoid calling qemuProcessStop without a job

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2021-12-01 10:56:58 +01:00
Ján Tomko
8a51f4c6e4 qemu: qemuDomainObjExitMonitor: do not warn on unused result
This wrapper for qemuDomainObjExitMonitorInternal was
extended by my commit dc2fd51fd7
to check whether the domain is still alive, because
we were observing crashes if the QEMU process died
while some of our APIs were in the monitor and the thread
processing the EOF event freed the domain definition.

This bug was fixed by:
    commit 81f50cb92d
    qemu: Avoid calling qemuProcessStop without a job
but we kept checking for the return value since.

Remove the G_GNUC_WARN_UNUSED_RESULT attribute since
all of the calls that could set def->id to -1 are protected
by qemuProcessBeginStopJob and cannot happen while we have a job
in the monitor.

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2021-12-01 10:56:58 +01:00
Or Ozeri
9696427ad6 qemu: add disk post parse to qemublocktest
The post parse callback is part of the real (non-test) processing flow.
This commit adds it (for disks) to the qemublocktest flow as well.
Specifically, this will be needed for tests that use luks encryption,
so that the default encryption engine (which is added in an upcoming commit)
will be overridden by qemu.

Signed-off-by: Or Ozeri <oro@il.ibm.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2021-10-25 14:06:15 +02:00
Peter Krempa
aee82fe616 conf: Introduce 'effectiveBootIndex' into 'virDomainDeviceInfo'
'effectiveBootIndex' is a copy of 'bootIndex' if '<boot order=' was
present and left unassigned if not. This allows hypervisor drivers to
reinterpret <os><boot> without being visible in the XML.

QEMU driver had a internal implementation for disks, which is now
replaced. Additionally this will simplify a refactor of network boot
assignment.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:26:02 +02:00
Ján Tomko
0b2a2e84e4 qemu: remove private data from virDomainFSDef
This reverts commit 801e6da29c

They are not needed anymore.

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2021-10-06 12:03:12 +02:00
Ján Tomko
1c9d4f9ea3 qemu: domain: introduce qemuDomainGetVHostUserFSSocketPath
Intended as a replacement for qemuVirtioFSCreateSocketFilename,
to be used outside of qemu_virtiofs.c

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2021-10-06 12:03:12 +02:00
Michal Privoznik
9985f62b51 qemu: Wire up MEMORY_DEVICE_SIZE_CHANGE event
As advertised in previous commit, this event is delivered to us
when virtio-mem module changes the allocation inside the guest.
It comes with one attribute - size - which holds the new size of
the virtio-mem (well, allocated size), in bytes.
Mind you, this is not necessarily the same number as 'requested
size'. It almost certainly will be when sizing the memory up, but
it might not be when sizing the memory down - the guest kernel
might be unable to free some blocks.

This current size is reported in the domain XML as an output
element only.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-01 11:04:47 +02:00
Peter Krempa
db66d0247a qemu: Simplify qemuDomainSecretInfo
Now that we've removed support for plaintext secrets qemuDomainSecretInfo
can be simplified by removing the 'type' field and merging in all the
fields from 'qemuDomainSecretAES'.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-09-22 14:53:56 +02:00
Peter Krempa
ed98e8ec99 qemu: Remove VIR_DOMAIN_SECRET_INFO_TYPE_PLAIN and associated code
There's no code which could set it any more so we can remove the
generators.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-09-22 14:53:56 +02:00
Peter Krempa
3d13acc3bc qemu: domain: Remove qemuDomainSupportsEncryptedSecret
The answer is now always 'true', so we can remove the function and
simplify the logic in places where it's called.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-09-22 14:53:55 +02:00
Peter Krempa
7dee442677 conf: validate: Move qemu-specific LUN disk validation to global validation
LUN disks are supported only by VMX and QEMU drivers and the VMX
implementation is a subset of qemu's implementation, thus we can move
the qemu-specific validator to the global validation code providing that
we allow the format to be 'none' (qemu driver always sets 'raw' if it's
not set) and allow disk type 'volume' as a source (qemu always
translates the source, and VMX doesn't implement 'volume' at all).

Moving the code to the global validation allows us to stop calling it
from the qemu specific validation and also deduplicates the checks.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2021-09-09 10:17:28 +02:00
Peter Krempa
fa11852433 qemu: domain: Remove qemuDomainIsUsingNoShutdown
Directly use 'priv->allowReboot' as we now document what the behaiour is
to avoid another lookup.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2021-08-25 15:32:44 +02:00
Peter Krempa
6ab6d3f074 qemuDomainObjPrivate: Annotate 'allowReboot' field
Save further readers the headache of determining what it actually does
and note that it's not used with qemu version supporting the
'set-action' command.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2021-08-25 15:32:44 +02:00
Michal Privoznik
b5958b2863 qemuDomainOpenFile: Take @cfg instead of driver
Again, we don't need full driver, just its config.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Tested-by: Ján Tomko <jtomko@redhat.com>
2021-08-16 09:24:38 +02:00
Michal Privoznik
e0dcdaefe2 qemuDomainOpenFile: Take virDomainDef instead of virDomainObj
The function doesn't really need domain object, but domain
definition from which it takes seclabels.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Tested-by: Ján Tomko <jtomko@redhat.com>
2021-08-16 09:24:05 +02:00
Peter Krempa
93a42f8507 qemu: domain: Store passthrough arguments in NULL-terminated string list
We always process the full list so there's no value in storing the count
separately.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-08-09 10:09:00 +02:00
Peter Krempa
d1aa253730 qemu: domain: Store capability overrides in NULL-terminated string list
We always process the full list so there's no value in storing the count
separately.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-08-09 10:09:00 +02:00
Peter Krempa
b7b8ea965b qemu: domain: Store passthrough environment variables in a struct
Previously they were stored in two separate arrays. This way it's
obvious when referencing the same one.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-08-09 10:09:00 +02:00
Peter Krempa
e637d34277 qemuDomainCheckCCWS390AddressSupport: Remove duplicated checker
For validation of explicitly configured addresses we already ported the
same style of checks to qemuValidateDomainDeviceDefAddress and implicit
address assignment should do the right thing in the first place, thus
the function is redundant and can be removed.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-06-15 16:58:23 +02:00
Michal Privoznik
b159ff83a5 qemuDomainSupportsVideoVga: Fix const correctness
This function doesn't modify passed video definition. Make the
argument const.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2021-06-11 21:53:40 +02:00
Peter Krempa
34c3291139 qemu: Track creation of <transient> disk overlay individually
In preparation for hotplug of <transient> disks we'll need to track
whether the overlay file was created individually per-disk.

Add 'transientOverlayCreated' to 'struct _qemuDomainDiskPrivate' and
remove 'inhibitDiskTransientDelete' from 'qemuDomainObjPrivate' and
adjust the code for the change.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2021-05-24 20:38:08 +02:00
Peter Krempa
2976b6aaeb qemu: Move 'bootindex' handling for disks out of command line formatter
The logic assigning the bootindices from the legacy boot order
configuration was spread through the command line formatters for the
disk device and for the floppy controller.

This patch adds 'effectiveBootindex' property to the disk private data
which holds the calculated boot index and moves the logic of determining
the boot index into 'qemuProcessPrepareDomainDiskBootorder' called from
'qemuProcessPrepareDomainStorage'.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2021-05-24 20:38:07 +02:00
Tim Wiederhake
5729d94917 Fix spelling
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>
2021-04-15 15:42:21 +02:00
Michal Privoznik
c8238579fb lib: Drop internal virXXXPtr typedefs
Historically, we declared pointer type to our types:

  typedef struct _virXXX virXXX;
  typedef virXXX *virXXXPtr;

But usefulness of such declaration is questionable, at best.
Unfortunately, we can't drop every such declaration - we have to
carry some over, because they are part of public API (e.g.
virDomainPtr). But for internal types - we can do drop them and
use what every other C project uses 'virXXX *'.

This change was generated by a very ugly shell script that
generated sed script which was then called over each file in the
repository. For the shell script refer to the cover letter:

https://listman.redhat.com/archives/libvir-list/2021-March/msg00537.html

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2021-04-13 17:00:38 +02:00
Peter Krempa
a6444c8019 qemu: Add per-VM control of deprecation behavior
Similar to the qemu.conf knob 'deprecation_behavior' add a per-VM knob
in the QEMU namespace:

  <qemu:deprecation behavior='...'/>

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
2021-04-06 17:07:56 +02:00
Peter Krempa
516906d681 qemu: domain: Store list of temporary bitmaps for migration in status XML
Add status XML infrastructure for storing a list of block dirty bitmaps
which are temporarily used when migrating a VM with
VIR_MIGRATE_NON_SHARED_DISK for cleanup after a libvirtd restart during
migration.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
2021-02-20 13:21:21 +01:00
Daniel P. Berrangé
970a59d746 qemu: implement virDomainGetMessages API
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2021-02-12 09:19:13 +00:00
Peter Krempa
4ebc278657 qemu: Convert 'priv->dbusVMStateIds' to a GSList
The conversion removes the use of virStringListAdd/virStringListRemove
which try to add dynamic properties to a string list which is really
inefficient.

Storing the dbus VMState ids in a GSList is pretty straightforward and
the slightly increased complexity of the code will be paid back by
removing the string list helpers later.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2021-02-11 17:05:32 +01:00
Daniel P. Berrangé
30626ed15b qemu: add ability to associate a string message with taint warning
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2021-02-03 17:31:31 +00:00
Peter Krempa
40242b7452 qemuDomainGetStorageSourceByDevstr: Lookup also backup 'store' nodenames
Nodename may be asociated to a disk backup job, add support to looking
up in that chain too. This is specifically useful for the
BLOCK_WRITE_THRESHOLD event which can be registered for any nodename.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-12-08 15:12:34 +01:00
Peter Krempa
c1720b9ac7 qemuDomainDiskLookupByNodename: Lookup also backup 'store' nodenames
Nodename may be asociated to a disk backup job, add support to looking
up in that chain too. This is specifically useful for the
BLOCK_WRITE_THRESHOLD event which can be registered for any nodename.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-12-08 15:12:34 +01:00
Michal Privoznik
d4eb2aabca qemu: Drop @qemuCaps argument from qemuDomainDefValidateMemoryHotplug()
After previous cleanup the @qemuCaps argument in
qemuDomainDefValidateMemoryHotplug() is unused and thus doesn't
need to be passed.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2020-12-04 17:01:37 +01:00
Peter Krempa
926563dc3a qemuDomainSnapshotForEachQcow2: Pass in 'def' rather than selecting it internally
In some cases such as when creating an internal inactive snapshot we
know that the domain definition in the snapshot is equivalent to the
current definition. Additionally we set up the current definition for
the snapshotting but not the one contained in the snapshot. Thus in some
cases the caller knows better which def to use.

Make qemuDomainSnapshotForEachQcow2 take the definition by the caller
and copy the logic for selecting the definition to callers where we
don't know for sure that the above claim applies.

This fixes internal inactive snapshots when <disk type='volume'> is used
as we translate the pool/vol combo only in the current def.

Resolves: https://gitlab.com/libvirt/libvirt/-/issues/97
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2020-11-24 17:59:26 +01:00
Daniel P. Berrangé
044eed3f94 qemu: add helper method for checking if ESP SCSI is builtin
The NCR53C90 ESP SCSI controller is only usable when built-in to the
machine type. This method will facilitate checking that restriction
across many places.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2020-11-20 12:09:51 +00:00
Nikolay Shirokovskiy
1f209eac1d qemu: remove duplicate code for removing remnant files
This patch also changes functionality a bit.

First if unlinking of old config file is failed we rollback and return error
previously and now we return success. I don't think this makes much difference.
I guess in both cases on libvirtd restart we have to deal with both new and old
config existing on disk with different names but same uuid.

Second if unlinking of old autolink is failed we rollback previously which
was not right as at this point we already unlink old config file. So this
is fixed now.

Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
2020-11-13 14:49:50 +03:00
Peter Krempa
62a01d84a3 util: hash: Retire 'virHashTable' in favor of 'GHashTable'
Don't hide our use of GHashTable behind our typedef. This will also
promote the use of glibs hash function directly.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Matt Coleman <matt@datto.com>
2020-11-06 10:40:51 +01:00
Peter Krempa
d6d4c08daf util: hash: Change type of hash table name/key to 'char'
All users of virHashTable pass strings as the name/key of the entry.
Make this an official requirement by turning the variables to 'const
char *'.

For any other case it's better to use glib's GHashTable.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2020-10-22 15:02:46 +02:00
Michal Privoznik
0b66196d86 qemu: Set noqueue qdisc for TAP devices
By default, pfifo_fast queueing discipline (qdisc) is set on
newly created interfaces (including TAPs). This qdisc has three
queues and packets that want to be sent through given NIC are
placed into one of the queues based on TOS field. Queues are then
emptied based on their priority allowing interactive sessions
stay interactive whilst something else is downloading a large
file.

Obviously, this means that kernel has to be involved and some
locking has to happen (when placing packets into queues). If
virtualization is taken into account then the above algorithm
happens twice - once in the guest and the second time in the
host.

This is arguably not optimal as it burns host CPU cycles
needlessly. Guest already made it choice and sent packets in the
order it wants.

To resolve this, Linux kernel offers 'noqueue' qdisc which can be
applied on virtual interfaces and in fact for 'lo' it is by
default:

  lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue

Set it for other TAP devices we create for domains too. With this
change I was able to squeeze 1Mbps more from a macvtap attached
to a guest and to my 1Gbps LAN (as measured by iperf3).

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1329644
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
2020-10-13 16:31:29 +02:00