11804 Commits

Author SHA1 Message Date
Peter Krempa
3d4f0aba0d qemuBlockStorageSourceAttachRollback: Sanitize warning messages
Mention the QMP command 'device_add' rather than 'qemuMonitorAddDevice'
and remove the weird formatting.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:26:01 +02:00
Peter Krempa
fbc088ab82 qemuMonitorJSONAddDeviceProps: Refactor cleanup
Use automatic memory freeing and remove 'ret' variable and 'cleanup'
label.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:26:01 +02:00
Peter Krempa
2154718c29 qemu: Rename 'qemuMonitorAddDeviceArgs' to 'qemuMonitorAddDeviceProps'
We commonly use 'props' for the JSON object describing something. Rename
the monitor device addition code.

Additionally the common approach is to clear the pointer if it was
consumed so the arguments are adjusted to do so.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:26:01 +02:00
Peter Krempa
daaa28d774 qemuDomainHotplugAddVcpu: Refactor cleanup
Use g_autoptr for 'vcpuprops' and remove the 'cleanup' label and 'ret'
varlaible which is no longer needed.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:26:01 +02:00
Peter Krempa
605a1e9d2e qemu: Move watchdog model validation into the validation code
Report the error from 'qemuValidateDomainWatchdogDef' rather than
'qemuBuildWatchdogDevStr'.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:26:01 +02:00
Peter Krempa
7c48fa2f58 qemu: capabilities: Introduce QEMU_CAPS_DEVICE_JSON
The flag will be used to switch use of JSON arguments for -device once
qemu will support it.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:26:00 +02:00
Peter Krempa
1a97c8f50e qemu: capabilities: Introduce QEMU_CAPS_CHARDEV_JSON
The flag will be used to switch use of JSON arguments for -chardev once
qemu will support it.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:26:00 +02:00
Peter Krempa
803d3f2ca0 virQEMUBuildDriveCommandlineFromJSON: Open-code in callers
Optimize the number of string copies by using the virBuffers in the
callers directly. Simplest way to achieve this is to just open code the
one function call 'virQEMUBuildDriveCommandlineFromJSON' was wrapping
in the two callers.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:26:00 +02:00
Peter Krempa
424dc5d2d2 qemu: Remove 'qemuBuildCommandLineFlags' and associated code
The -netdev formatter code switched to a real virQEMUCaps flag so we can
remove the old flags which used to enable JSON for -netdev for
validation purposes.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:26:00 +02:00
Peter Krempa
63a833038f qemu: command: Format netdev as JSON when QEMU_CAPS_NETDEV_JSON is present
Base the JSON output on a regular capability flag rather than purely
internal flag. This will prepare for the time when QEMU will accept JSON
argumets for -netdev.

For now the capability is not set (thus we for now don't have QMP
schema validation) but that will be addressed later.

To achieve this 'qemuBuildNetdevCommandlineFromJSON' is introduced
and all callers of 'virQEMUBuildNetdevCommandlineFromJSON' are
refactored to use the new helper.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:26:00 +02:00
Peter Krempa
c6a9285925 qemuBuildObjectCommandlineFromJSON: Remove checks for 'type' and 'alias'
We validate the generated props against the QMP schema which makes sure
that the objects are generated properly.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:26:00 +02:00
Peter Krempa
cacfd540f0 qemu: capabilities: Introduce QEMU_CAPS_NETDEV_JSON
Introduce a capability that will be asserted once '-netdev' will accept
JSON. For now it will be dormant (only used by tests).

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:26:00 +02:00
Peter Krempa
2e2d871773 qemu: capabilities: Rename QEMU_CAPS_OBJECT_QAPIFIED to QEMU_CAPS_OBJECT_JSON
Unify it with the upcoming capabilities for -netdev and -device.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:25:59 +02:00
Peter Krempa
6da02fecca qemuBuildObjectCommandlineFromJSON: Format directly into the virCommand
All callers basically end up dumping the buffer into a string and then
adding '-object' 'props' arguments to virCommand. Simplify all callers
by doing this in the function itself.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:25:59 +02:00
Peter Krempa
f8f9c49302 qemuBuildInputDevStr: Don't mix generators for -object and -device
Input devices of VIR_DOMAIN_INPUT_TYPE_EVDEV type are instantiated via
an '-object' rather than a '-device'. Mixing them in one function is a
bad idea as the caller then needs to use the string correctly which is
not the case in 'qemuDomainAttachInputDevice'.

Generate a JSON object for '-object' explicitly.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:25:59 +02:00
Peter Krempa
d8f3fb187d qemuBuildMemoryCellBackendStr: Return JSON props instead of a buffer
Rename the function to 'qemuBuildMemoryCellBackendProps' and return the
properties before conversion to commandline arguments. This requires
changes in the caller.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 10:25:59 +02:00
Peter Krempa
618e8665db qemu: capabilities: Remove QEMU_CAPS_PIIX4_ACPI_HOTPLUG_BRIDGE
Commit 58ba0f6a3d7342fba29edbbf2bb9cb5497c870e5 added a capability which
is supported by all qemu versions we support. Remove it and the
associated dead code. Since the capability isn't present in any upstream
release we can delete it completely.

Specifically the commit itself states that it was introduced "around
(qemu) 2.1". The rest of the code handles properly that the feature is
used only on x86 with the i440fx machine so the capability is pointless.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 09:41:22 +02:00
Peter Krempa
bdc3e8f47b qemuValidateDomainDefPCIFeature: Fix validation logic
The error that "acpi-bridge-hotplug" is not supported would be triggered
only if both the ICH9 and PIIX don't support the capability and the
machine is q35. This makes no sense.

We want to check that the appropriate platform supports the appropriate
feature.

Fixes: 7300ccc9b3e
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 09:41:22 +02:00
Peter Krempa
7d074c5683 qemuValidateDomainDefPCIFeature: un-break error messages
https://www.libvirt.org/coding-style.html#error-message-format

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-12 09:41:22 +02:00
Ani Sinha
bef0f0d8be qemu: command: add support for acpi-bridge-hotplug feature
This change adds backend qemu command line support for new libvirt
global feature 'acpi-bridge-hotplug'. This option can be used as
following:

<feature>
  <pci>
    <acpi-bridge-hotplug state='off|on'/>
  </pci>
</feature>

The '<pci>' sub-element under '<feature>' is also newly introduced.

'acpi-bridge-hotplug' turns on the following command line option to
qemu for x86 guests:

(pc): -global PIIX4_PM.acpi-pci-hotplug-with-bridge-support=<off|on>

(q35): -global ICH9-LPC.acpi-pci-hotplug-with-bridge-support=<off|on>

This change also adds the required qemuxml2argv unit tests in order to
test correct qemu arguments. Unit tests have also been added to test
qemu capability validation checks as well as checks for using this
option with the right architecture.

Signed-off-by: Ani Sinha <ani@anisinha.ca>
Reviewed-by: Laine Stump <laine@redhat.com>
2021-10-10 13:21:04 -04:00
Ani Sinha
7300ccc9b3 conf: introduce support for acpi-bridge-hotplug feature
This change introduces a new libvirt sub-element <pci> under
<features> that can be used to configure all pci related features.
Currently the only sub-sub element supported by this sub-element is
'acpi-bridge-hotplug' as shown below:

<features>
  <pci>
    <acpi-bridge-hotplug state='on|off'/>
  </pci>
</features>

The above option is only available for the QEMU driver, for x86 guests
only. It is a global option, affecting all PCI bridge controllers on
the guest.

The 'acpi-bridge-hotplug' option enables or disables ACPI hotplug
support for cold-plugged pci bridges. Examples of bridges include the
PCI-PCI bridge (pci-bridge controller) for pc (i440fx) machinetypes,
or PCIe-PCI bridges and pcie-root-port controllers for q35
machinetypes.

For pc machinetypes in x86, this option has been available in QEMU
since version 2.1. Please see the following changes in qemu repo:

9e047b982452c6 ("piix4: add acpi pci hotplug support")
133a2da488062e ("pc: acpi: generate AML only for PCI0 devices if PCI
               bridge hotplug is disabled")

For q35 machinetypes, this was introduced in QEMU 6.1 with the
following changes in qemu repo:

(a) c0e427d6eb5fef ("hw/acpi/ich9: Enable ACPI PCI hot-plug")
(b) 17858a16950860 ("hw/acpi/ich9: Set ACPI PCI hot-plug as default on
                   Q35")

The reasons for enabling ACPI based hotplug for PCIe (q35) based
machines (as opposed to native hotplug) are outlined in (b). There are
use cases where users would still want to use native
hotplug. Therefore, this config option enables users to choose either
ACPI based hotplug or native hotplug for bridges (for example for pcie
root port controller in q35 machines).

Qemu capability validation checks have also been added along with
related unit tests to exercise the new conf option.

Signed-off-by: Ani Sinha <ani@anisinha.ca>
Reviewed-by: Laine Stump <laine@redhat.com>
2021-10-10 13:13:45 -04:00
Ani Sinha
58ba0f6a3d qemu: capablities: detect acpi-pci-hotplug-with-bridge-support
qemu added support for i440fx specific global boolean flag

PIIX4_PM.acpi-pci-hotplug-with-bridge-support

around version 2.1. This flag is enabled by default. When disabled, it
turns off acpi pci hotplug for cold plugged pci bridges in i440fx
machine types.

Very recently, in qemu version 6.1, the same global option was also
added for q35 machine types as well.

ICH9-LPC.acpi-pci-hotplug-with-bridge-support

This option turns on or off acpi based hotplug for cold plugged pcie
bridges like pcie root ports. This flag is also enabled by
default. Please refer to the following qemu changes:

c0e427d6eb5fef ("hw/acpi/ich9: Enable ACPI PCI hot-plug")
17858a16950860 ("hw/acpi/ich9: Set ACPI PCI hot-plug as default on Q35")

This patch adds the corresponding qemu capabilities in libvirt. For
i440fx, the capability is detected as
QEMU_CAPS_PIIX_ACPI_HOTPLUG_BRIDGE. For q35, the capability is
detected as QEMU_CAPS_ICH9_ACPI_HOTPLUG_BRIDGE.

Please note that the test specific qemu capabilities .replies files
has already been updated as a part of regular refreshing them when a
new qemu version is released. Hence, no updates to those files are
required.

Signed-off-by: Ani Sinha <ani@anisinha.ca>
Reviewed-by: Laine Stump <laine@redhat.com>
2021-10-10 13:12:50 -04:00
Ján Tomko
b96ca3b848 qemu: export vhost-user-fs-related functions
Prepare for hotplug support.

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
842ffd1563 qemu: vhost-user-fs: build extdevice for zpci
Other devices (includes 9p-based fsdev) call this wrapper
before formatting the device.

Add it here too.

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
c172a3733e qemu: alias: prepare qemuAssignDeviceFSAlias for disjunct ranges
Iterate through the array to find the first free index.

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
0b2a2e84e4 qemu: remove private data from virDomainFSDef
This reverts commit 801e6da29c0202946d44b42136cc4ee229932a29

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
e7801a490c qemu: do not put virtiofs socket in private data
Reconstruct the socket path from priv->libDir in every user.

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
cf5b3482c1 qemu: vhost-user-fs: separate building of device string
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
387e265f90 qemu: vhost-user-fs: separate building of chardev string
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
Ján Tomko
da4efc5433 qemu: vhost-user-fs: format alias on the command line
The commit adding the vhost-user-fs device forgot to format
the device's alias on the command line.

Thankfully it was not needed yet because virtiofs migration
is not yet supported, but it will be needed in the future
to allow hot(un)plug.

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2021-10-06 12:03:11 +02:00
Michal Privoznik
f60bc4f620 qemu: Check if unpriv_sgio is already set before trying to set it
In case when libvirt runs inside a restricted container it may
not have enough permissions to modify unpriv_sgio. However, it
may have been set beforehand by sysadmin or an orchestration
tool. Therefore, let's check whether the currently set value is
the one we want and if it is refrain from writing to the file.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2010306
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-05 14:58:52 +02:00
Ani Sinha
400979fd06 qemu: capabilities: remove -en from piix4-acpi-root-hotplug-en
The capability name piix4-acpi-root-hotplug-en is not conventional and
appreared to be confusing to some. "en" suffix is also incorrect as the
capability in qemu is used to both enable and disable hotplug on the pci root
bus on the i440fx. Hence, rename it to piix4.acpi-root-pci-hotplug so that it
is clearer, less confusing and more accurate.

Signed-off-by: Ani Sinha <ani@anisinha.ca>
Reviewed-by: Laine Stump <laine@redhat.com>
2021-10-05 00:07:23 -04:00
Ani Sinha
133d7983d6 qemu: command: add support to enable/disable hotplug on pci-root controller
This change adds qemu backend command line support for enabling or disabling
hotplug on the pci-root controller using the 'target' sub-element of the
pci-root controller as shown below:

<controller type='pci' model='pci-root'>
  <target hotplug='off'/>
</controller>

'<target hotplug='off/on'/>' is only valid for pc (i440fx-based x86)
machinetypes and turns on the following command line option that is passed
to qemu for x86 guests:

-global PIIX4_PM.acpi-root-pci-hotplug=<off/on>

Before introduction of this attribute, hotplug was always enabled for
pci-root of an i440fx-based machinetype, and since its introduction
the default setting has always been "on" for those machinetypes.

This change also adds the required qemuxml2argv unit tests in order to test
correct qemu arguments. Unit tests have also been added to test qemu capability
validation checks.

Signed-off-by: Ani Sinha <ani@anisinha.ca>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Laine Stump <laine@redhat.com>
2021-10-01 14:42:18 -04:00
Ani Sinha
8eadf82fb5 conf: introduce option to enable/disable pci hotplug on pci-root controller
This change introduces libvirt xml support to enable/disable hotplug on the
pci-root controller. It adds a 'target' subelement for the pci-root controller
with a 'hotplug' property. This property can be used to enable or disable
hotplug for the pci-root controller. For example, in order to disable hotplug
on the pci-root controller, one has to use set '<target hotplug='off'>' as
shown below:

<controller type='pci' model='pci-root'>
  <target hotplug='off'/>
</controller>

'<target hotplug='on'>' option would enable hotplug for pci-root controller.
This is also the default value. This option is only available for pc machine
types and is applicable for qemu/kvm accelerator only.This feature was
introduced from qemu version 5.2 with the following change in qemu repository:

3d7e78aa7777f ("Introduce a new flag for i440fx to disable PCI hotplug on the root bus")

The above qemu commit describes some reasons why users might to disable hotplug
on PCI root buses.

Related unit tests to exercise the new conf option has also been added.

Signed-off-by: Ani Sinha <ani@anisinha.ca>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Laine Stump <laine@redhat.com>
2021-10-01 14:19:44 -04:00
Ani Sinha
fdec09b00a qemu: capablities: detect presence of acpi-root-pci-hotplug for i440fx machines
The following change in qemu added support for a global boolean flag specific
to i440fx machines that would turn off or on acpi based hotplug for pci root
bus:

3d7e78aa7777f ("Introduce a new flag for i440fx to disable PCI hotplug on the root bus")

The option is passed as "-global PIIX4_PM.acpi-root-pci-hotplug=on" etc in qemu
commandline. It is enabled by default. This patch adds the corresponding qemu
capabilities in libvirt as QEMU_CAPS_PIIX_ACPI_ROOT_PCI_HOTPLUG.

Please note that the test specific qemu capabilities .replies files has already
been updated as a part of regular refreshing them when a new qemu version is
released. Hence, no updates to those files are required.

Signed-off-by: Ani Sinha <ani@anisinha.ca>
Reviewed-by: Laine Stump <laine@redhat.com>
2021-10-01 14:19:41 -04:00
Michal Privoznik
b1c3b5dfec qemuDomainSetMemoryFlags: Take virtio-mem into consideration
The qemuDomainSetMemoryFlags() allows for memballoon
(<currentMemory/>) changes for both active and inactive guests.
And just before doing any change, we have to make sure that the
new size is not greater than the total memory (<memory/>).

However, the total memory includes not only the regular guest
memory, but also sum of maximum sizes of all virtio-mems (in fact
all memory devices for that matter). But virtio-mem devices are
modified differently (via virDomainUpdateDevice()) and thus the
upper limit for new balloon size has to be lowered.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-01 11:05:02 +02:00
Michal Privoznik
51f65e9522 qemu: Account for both memballoon and virtio-mem
Reporting how much memory is exposed to the guest happens under
<currentMemory/> which is taken from def->mem.cur_balloon. The
reported amount should account for both balloon size and the sum
of @currentsize of all virtio-mems. For instance, if domain has
4GiB via balloon and additional 2GiB via virtio-mem, then the
domain XML should report 6GiB. The same applies for domain
statistics.

The way to achieve this is to account for either balloon or
virtio-mem when the size of the other is changed, e.g. on balloon
change we have to add all @currentsize (for non virtio-mem these
will be zero, so the check for memory model is needless, but
makes it more obvious what's happening), and vice versa.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-01 11:04:57 +02:00
Michal Privoznik
5c2d6908a6 qemu: Refresh the current size of virtio-mem on monitor reconnect
If the QEMU driver restarts it loses the track of the current size
of virtio-mem (because it's runtime type of information and thus
not stored in XML) and therefore, we have to refresh it when
reconnecting to the domain monitor.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-01 11:04:53 +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
Michal Privoznik
99e4ae2b02 qemu: Wire up <memory/> offline update
Updating offline XML of <memory/> devices might come handy when
dealing with virtio-mem devices. But it's implemented to just
replace one virDomainMemoryDef with another so it can be used to
change almost anything.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-01 11:04:21 +02:00
Michal Privoznik
3ec559661a qemu: Wire up <memory/> live update
As advertised in one of previous commits, we want to be able to
change 'requested-size' attribute of virtio-mem on the fly. This
commit does exactly that. Changing anything else is checked for
and forbidden.

Once guest has changed the allocation, QEMU emits an event which
we will use to track the allocation. In the next commit.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-01 11:04:16 +02:00
Michal Privoznik
363866a1e2 qemu: Build command line for virtio-mem
Nothing special is happening here. All important changes were
done when for 'virtio-pmem' (adjusting the code to put virtio
memory on PCI bus, generating alias using
qemuDomainDeviceAliasIndex(). The only bit that might look
suspicious is no prealloc for virtio-mem. But if you think about
it, the whole purpose of this device is to change amount of
memory exposed to guest on the fly. There is no point in locking
the whole backend in memory.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-01 11:04:05 +02:00
Michal Privoznik
f931cb7f21 conf: Introduce virtio-mem <memory/> model
The virtio-mem is paravirtualized mechanism of adding/removing
memory to/from a VM. A virtio-mem-pci device is split into blocks
of equal size which are then exposed (all or only a requested
portion of them) to the guest kernel to use as regular memory.
Therefore, the device has two important attributes:

  1) block-size, which defines the size of a block
  2) requested-size, which defines how much memory (in bytes)
     is the device requested to expose to the guest.

The 'block-size' is configured on command line and immutable
throughout device's lifetime. The 'requested-size' can be set on
the command line too, but also is adjustable via monitor. In
fact, that is how management software places its requests to
change the memory allocation. If it wants to give more memory to
the guest it changes 'requested-size' to a bigger value, and if it
wants to shrink guest memory it changes the 'requested-size' to a
smaller value. Note, value of zero means that guest should
release all memory offered by the device. Of course, guest has to
cooperate. Therefore, there is a third attribute 'size' which is
read only and reflects how much memory the guest still has. This
can be different to 'requested-size', obviously. Because of name
clash, I've named it 'current' and it is dealt with in future
commits (it is a runtime information anyway).

In the backend, memory for virtio-mem is backed by usual objects:
memory-backend-{ram,file,memfd} and their size puts the cap on
the amount of memory that a virtio-mem device can offer to a
guest. But we are already able to express this info using <size/>
under <target/>.

Therefore, we need only two more elements to cover 'block-size'
and 'requested-size' attributes. This is the XML I've came up
with:

  <memory model='virtio-mem'>
    <source>
      <nodemask>1-3</nodemask>
      <pagesize unit='KiB'>2048</pagesize>
    </source>
    <target>
      <size unit='KiB'>2097152</size>
      <node>0</node>
      <block unit='KiB'>2048</block>
      <requested unit='KiB'>1048576</requested>
    </target>
    <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
  </memory>

I hope by now it is obvious that:

  1) 'requested-size' must be an integer multiple of
     'block-size', and
  2) virtio-mem-pci device goes onto PCI bus and thus needs PCI
     address.

Then there is a limitation that the minimal 'block-size' is
transparent huge page size (I'll leave this without explanation).

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-01 11:02:53 +02:00
Michal Privoznik
ed7c51b42e qemu_capabilities: Introduce QEMU_CAPS_MEMORY_BACKEND_RESERVE
This capability tracks whether memory-backend-* supports .reserve
attribute which is going to be important for backends associated
with virtio-mem devices.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-01 11:02:09 +02:00
Michal Privoznik
284d9c46d7 qemu_capabilities: Introduce QEMU_CAPS_DEVICE_VIRTIO_MEM_PCI
This commit introduces a new capability that reflects virtio-mem-pci
device support in QEMU:

  QEMU_CAPS_DEVICE_VIRTIO_MEM_PCI, /* -device virtio-mem-pci */

The virtio-mem-pci device was introduced in QEMU 5.1.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2021-10-01 11:01:32 +02:00
Michal Privoznik
9c47d2754c qemuBuildNumaCommandLine: Separate out building of CPU list
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2021-10-01 10:52:35 +02:00
Michal Privoznik
c9f47bfc7a qemuBuildNumaCommandLine: Move vars into loops
There are two variables that are used only in a single
loop. Move their definitions into their respective blocks.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2021-10-01 10:52:35 +02:00
Ján Tomko
0522f02f35 qemu: deprecate QEMU_CAPS_FSDEV_CREATEMODE
Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2021-09-27 10:11:22 +02:00
Ján Tomko
43fac71b70 qemu: assume QEMU_CAPS_FSDEV_CREATEMODE
Added by QEMU commit:
b96feb2cb9 "9pfs: local: Add support for custom fmode/dmode in 9ps
mapped security modes"
in 2.10.0

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2021-09-27 10:11:22 +02:00