On Sun, Sep 12, 2021 at 08:56:29AM +0530, Ani Sinha wrote:
> This change introduces libvirt xml support for the following two pm options:
>
> <pm>
> <acpi-hotplug-bridge enabled='no'/>
> <acpi-root-hotplug enabled='yes'/>
> </pm>
> +``acpi-hotplug-bridge``
> + :since:`Since 7.8.0` This option enables or disables BIOS ACPI based
> hotplug support
> + for cold plugged bridges. It is available only for x86 guests, both for
> q35 and pc
> + machine types. For pc machines, the support is available from `QEMU
> 2.12`. For q35
> + machines, the support is available from `QEMU 6.1`. Examples of cold
> plugged bridges
> + include PCI-PCI bridges for pc machine types (pci-bridge controller). For
> q35 machines,
> + it includes PCIE root ports (pcie-root-port controller). This is a global
> option that
> + affects all bridges. No other bridge specific option is required to be
> specified.
Can you confirm my understanding of the situation..
- i440fx / PCI topology - hotplug always uses ACPI
- q35 / PCIe topology - hotplug historically used native PCIe hotplug,
but in 6.1 switched to ACPI
Given, the name "acpi-hotplug-bridge", am I right that this option
has *no* effect, if the q35 machine is using native PCIe hotplug
approach ? IOW, is it a no-op until 6.1 based machine types for q35 ?
Regards,
Daniel
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