Re: [PATCH v3 10/26] accel/mshv: Add vCPU creation and execution loop

[Magnus Kulke <magnuskulke@linux.microsoft.com>]

On Wed, Aug 27, 2025 at 12:24:39PM +0100, Daniel P. Berrangé wrote:
> So every MSHV  vCPU has a corresponding Linux thread, similar
> to the model with KVM.  In libvirt we rely on the vCPU thread
> being controllable with all the normal Linux process related
> APIs. For example, setting thread CPU affinity, setting NUMA
> memory policy, setting scheduler priorities, putting threads
> into cgroups and applying a wide variety of cgroup controls.
> 
> Will there be any significant "gotchas" with the threads for
> MSHV vCPUs, that would mean the above libvirt controls would
> either raise errors, or silently not have any effect ?
> 

Hi Daniel,

I am not aware of any such gotchas. The MSHV vCPU threads should
be regular threads that spend most of their time blocked in
ioctl(MSHV_RUN) calls, and as such they should be controllable by
the facilities you mentioned. I know that that folks who tested this
code have been using numactl for reliable performance assessments
without running into issues.

best,

magnus