Intel Preparing Virtual IA32_SPEC_CTRL Support For The Linux Kernel

[phoronix]

Phoronix: Intel Preparing Virtual IA32_SPEC_CTRL Support For The Linux Kernel

Intel on Sunday posted a set of Linux patches implementing SPEC CTRL virtualization support for this VMX feature with new Intel CPUs to help with migrating virtual machines to hosts with different CPU microarchitectures where their security mitigations may be different...

https://www.phoronix.com/news/Intel-Virtual-IA32_SPEC_CTRL

[Lbibass]

Seems like this would be useful with xenon CPUs with a mix of E and P cores. Not sure if there were plans for that in their CPU timeline, but I guess it could be helpful if you’re making a node with both P and E cores depending on the needs of the users.

[tildearrow]

pass throughed -> passed through

[CommunityMember]

Seems like this would be useful with xenon CPUs with a mix of E and P cores. Not sure if there were plans for that in their CPU timeline, but I guess it could be helpful if you’re making a node with both P and E cores depending on the needs of the users.

The real use case, as documented in the patch, is for the hyperscalers and large datacenters with a mixed host environment where it is necessary to move VMs across different generations of hosts with different micro-architectural mitigation approaches for current (and future) architectural exploits. While some of the larger hyperscalers may be able to ensure that VMs are only migrated to to the same generation of hardware (because they have many many thousands of the same generation), that is certainly not a guarantee going forward. In some ideal world all hardware is perfect. We do not live in that world.

[hamishmb]

Interesting thought, probably not something I'd have considered, good that we've got smart people working on this stuff.