Bug 1955681

Summary: [RFE] Support vDPA devices without enabling real-time policy
Product: Red Hat OpenStack Reporter: Stephen Finucane <stephenfin>
Component: openstack-novaAssignee: Artom Lifshitz <alifshit>
Status: ASSIGNED --- QA Contact: nova-maint
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: dasmith, eglynn, jhakimra, kchamart, sbauza, sgordon, vromanso
Target Milestone: ---Keywords: FutureFeature, Triaged
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
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Last Closed: Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version: Xena
Bug Depends On: 1873409, 1939776    
Bug Blocks:    

Description Stephen Finucane 2021-04-30 16:19:25 UTC
Description of problem:

During Wallaby, we added support for creating instances with vDPA network devices. However, due to how this was implemented by QEMU/libvirt, it was necessary for users to enable the real-time policy ('hw:cpu_realtime=yes') to enable locked memory. Users shouldn't need to set this mostly unrelated set of tweaks to simply use vDPA. This could be resolved either by libvirt, which could increase the memlock limit via prlimit(2) as it does for VFIO devices, or nova could provide a way for users to request locked memory and only locked memory. This RFE tracks testing of the chosen solution along with any potential work needed in nova along the way.