6ce071f609
Before a PCI device can be assigned to a guest with VFIO, that device must be bound to the vfio-pci driver rather than to the device's normal host driver. The vfio-pci driver provides APIs that permit QEMU to perform all the necessary operations to make the device accessible to the guest. In the past vfio-pci was the only driver that supplied these APIs, but there are now vendor/device-specific "VFIO variant" drivers that provide the basic vfio-pci driver functionality/API while adding support for device-specific operations (for example these device-specific drivers may support live migration of certain devices). All that is needed to make this functionality available is to bind the vendor-specific "VFIO variant" driver to the device (rather than the generic vfio-pci driver, which will continue to work, just without the extra functionality). But until now libvirt has required that all PCI devices being assigned to a guest with VFIO specifically have the "vfio-pci" driver bound to the device. So even if the user manually binds a shiny new vendor-specific VFIO variant driver to the device (and puts "managed='no'" in the config to prevent libvirt from changing the binding), libvirt will just fail during startup of the guest (or during hotplug) because the driver bound to the device isn't exactly "vfio-pci". Beginning with kernel 6.1, it's possible to determine from the sysfs directory for a device whether the currently-bound driver is the vfio-pci driver or a VFIO variant - the device directory will have a subdirectory called "vfio-dev". We can use that to appropriately widen the list of drivers that libvirt will allow for VFIO device assignment. This patch doesn't remove the explicit check for the exact "vfio-pci" driver (since that would cause systems with pre-6.1 kernels to behave incorrectly), but adds an additional check for the vfio-dev directory, so that any VFIO variant driver is acceptable for libvirt to continue setting up for VFIO device assignment. Signed-off-by: Laine Stump <laine@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Libvirt API for virtualization
Libvirt provides a portable, long term stable C API for managing the virtualization technologies provided by many operating systems. It includes support for QEMU, KVM, Xen, LXC, bhyve, Virtuozzo, VMware vCenter and ESX, VMware Desktop, Hyper-V, VirtualBox and the POWER Hypervisor.
For some of these hypervisors, it provides a stateful management daemon which runs on the virtualization host allowing access to the API both by non-privileged local users and remote users.
Layered packages provide bindings of the libvirt C API into other languages including Python, Perl, PHP, Go, Java, OCaml, as well as mappings into object systems such as GObject, CIM and SNMP.
Further information about the libvirt project can be found on the website:
License
The libvirt C API is distributed under the terms of GNU Lesser General Public License, version 2.1 (or later). Some parts of the code that are not part of the C library may have the more restrictive GNU General Public License, version 2.0 (or later). See the files COPYING.LESSER and COPYING for full license terms & conditions.
Installation
Instructions on building and installing libvirt can be found on the website:
https://libvirt.org/compiling.html
Contributing
The libvirt project welcomes contributions in many ways. For most components the best way to contribute is to send patches to the primary development mailing list. Further guidance on this can be found on the website:
https://libvirt.org/contribute.html
Contact
The libvirt project has two primary mailing lists:
- libvirt-users@redhat.com (for user discussions)
- libvir-list@redhat.com (for development only)
Further details on contacting the project are available on the website: