During hotplug of a NVMe disk we need to adjust the memlock limit. The computation of the limit is handled by qemuDomainGetMemLockLimitBytes() which looks at given domain definition and accounts for various device types (as different types require different amounts). But during disk hotplug the disk is not added to domain definition until the very last moment. Therefore, qemuDomainGetMemLockLimitBytes() has this @forceVFIO argument which tells it to assume VFIO even if there are no signs of VFIO in domain definition. And this kind of works, until the amount needed for NVMe disks changed (in v9.3.0-rc1~52). What's missing in the commit is making @forceVFIO behave the same as if there was an NVMe disk present in the domain definition. But, we can do even better - just mimic whatever we're doing for hostdevs. IOW - introduce qemuDomainAdjustMaxMemLockNVMe() that behaves the same as qemuDomainAdjustMaxMemLockHostdev(). There are subtle differences though: 1) qemuDomainAdjustMaxMemLockHostdev() can afford placing hostdev right at the end of vm->def->hostdevs, because the array was already reallocated (at the beginning of qemuDomainAttachHostPCIDevice()). But qemuDomainAdjustMaxMemLockNVMe() doesn't have that luxury. 2) qemuDomainAdjustMaxMemLockHostdev() places a virDomainHostdevDef pointer into domain definition, while qemuDomainStorageSourceAccessModifyNVMe() (which calls qemuDomainAdjustMaxMemLock()) sees a virStorageSource pointer but domain definition contains virDomainDiskDef. But that's okay, we can create a dummy disk definition and append it into the domain definition. After this, qemuDomainAdjustMaxMemLock() can be called with @forceVFIO = false, as the disk is now part of domain definition (when computing the new limit). Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2014030#c28 Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Martin Kletzander <mkletzan@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: