On a Monday in 2021, Ani Sinha wrote:
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 only/kvm accelerator onlt.This feature was
s/onlt./only. /
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@xxxxxxxxxxx>
---
docs/formatdomain.rst | 12 ++++----
src/qemu/qemu_validate.c | 9 +++++-
.../pc-i440fx-acpi-root-hotplug-disable.xml | 30 +++++++++++++++++++
.../pc-i440fx-acpi-root-hotplug-enable.xml | 30 +++++++++++++++++++
.../pc-i440fx-acpi-root-hotplug-disable.xml | 1 +
.../pc-i440fx-acpi-root-hotplug-enable.xml | 1 +
tests/qemuxml2xmltest.c | 4 +++
7 files changed, 81 insertions(+), 6 deletions(-)
create mode 100644 tests/qemuxml2argvdata/pc-i440fx-acpi-root-hotplug-disable.xml
create mode 100644 tests/qemuxml2argvdata/pc-i440fx-acpi-root-hotplug-enable.xml
create mode 120000 tests/qemuxml2xmloutdata/pc-i440fx-acpi-root-hotplug-disable.xml
create mode 120000 tests/qemuxml2xmloutdata/pc-i440fx-acpi-root-hotplug-enable.xml
@@ -3879,6 +3879,14 @@ qemuValidateDomainDeviceDefControllerPCI(const virDomainControllerDef *cont,
/* hotplug */
if (pciopts->hotplug != VIR_TRISTATE_SWITCH_ABSENT) {
switch ((virDomainControllerModelPCI) cont->model) {
+ case VIR_DOMAIN_CONTROLLER_MODEL_PCI_ROOT:
+ if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_PIIX_ACPI_ROOT_PCI_HOTPLUG)) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ _("setting the %s property on a pci-root device is not supported by this QEMU binary"),
+ "hotplug");
No need to create a new translatable string, the one used by the case
below can be reused:
virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
_("setting the hotplug property on a '%s' device is not supported by this QEMU binary"),
"pci-root");
Jano
+ return -1;
+ }
+ break;
case VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT_PORT:
case VIR_DOMAIN_CONTROLLER_MODEL_PCIE_SWITCH_DOWNSTREAM_PORT:
if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_PCIE_ROOT_PORT_HOTPLUG)) {
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