Where are the acpiphp and pci_hotplug kernel modules for KVM hotplug in CentOS/RHEL?

Question

On the this how-to I read the following:

I loaded the following modules to get pci hotplug working:

• acpiphp
• pci_hotplug

You can either add these to your distro's module list to load on boot, or run a command like this.

for m in acpiphp pci_hotplug; do sudo modprobe ${m}; done

However, on CentOS 6.3 and Red Hat Enterprise Linux 6.3 this modules does not exist, on Ubuntu Server and Debian 6 it does.

Why? Any workaround?

Solution

Probably, it's already built into your kernel (rather than a module). Have you actually tried hotplugging devices?

I don't have access to a CentOS/RHEL machine now, but on Fedora, I see the kernel configuration contains this:

CONFIG_HOTPLUG_PCI=y
CONFIG_HOTPLUG_PCI_ACPI=y

While on Ubuntu 12.04, I see this:

CONFIG_HOTPLUG_PCI=y
CONFIG_HOTPLUG_PCI_ACPI=m

Comments

[Giovanni Bennelli]

CONFIG_HOTPLUG_PCI=y CONFIG_HOTPLUG_PCI_FAKE=m CONFIG_HOTPLUG_PCI_ACPI=y CONFIG_HOTPLUG_PCI_ACPI_IBM=m # CONFIG_HOTPLUG_PCI_CPCI is not set CONFIG_HOTPLUG_PCI_SHPC=m

[gertvdijk]

@GiovanniBennelli So, my thoughts are valid, right? Again: Have you actually tried hotplugging devices?

[Giovanni Bennelli]

ok, PCI hotplug support, in the guest, work fine.