Commit 10c73bf1 fixed a bug that I had introduced back in commit 70249927 - if a vhost-scsi device had no manually assigned PCI address, one wouldn't be assigned automatically. There was a slight problem with the logic of the fix though - in the case of domains with pcie-root (e.g. those with a q35 machinetype), qemuDomainDeviceCalculatePCIConnectFlags() will attempt to determine if the host-side PCI device is Express or legacy by examining sysfs based on the host-side PCI address stored in hostdev->source.subsys.u.pci.addr, but that part of the union is only valid for PCI hostdevs, *not* for SCSI hostdevs. So we end up trying to read sysfs for some probably-non-existent device, which fails, and the function virPCIDeviceIsPCIExpress() returns failure (-1). By coincidence, the return value is being examined as a boolean, and since -1 is true, we still end up assigning the vhost-scsi device to an Express slot, but that is just by chance (and could fail in the case that the gibberish in the "hostside PCI address" was the address of a real device that happened to be legacy PCI). Since (according to Paolo Bonzini) vhost-scsi devices appear just like virtio-scsi devices in the guest, they should follow the same rules as virtio devices when deciding whether they should be placed in an Express or a legacy slot. That's accomplished in this patch by returning early with virtioFlags, rather than erroneously using hostdev->source.subsys.u.pci.addr. It also adds a test case for PCIe to assure it doesn't get broken in the future.
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 2.1 (or later). See the files COPYING.LESSER
and COPYING
for full license terms & conditions.
Installation
Libvirt uses the GNU Autotools build system, so in general can be built and installed with the usual commands. For example, to build in a manner that is suitable for installing as root, use:
$ ./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var
$ make
$ sudo make install
While to build & install as an unprivileged user
$ ./configure --prefix=$HOME/usr
$ make
$ make install
The libvirt code relies on a large number of 3rd party libraries. These will
be detected during execution of the configure
script and a summary printed
which lists any missing (optional) dependencies.
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: