Re: [PATCH] KVM: VMX: CPU frequency scaling for intel x86_64 KVM guests

Paolo Bonzini
2022-05-31T18:11:46Z

On 5/31/22 13:43, Metin Kaya wrote:
> Thanks, Jack.
>
> Reviewed-by: Metin Kaya <metikaya@amazon.co.uk>
>

Please try a bit harder. "Reviewed-by" is neither "this matches what's
been forever in the Amazon kernel" nor "I guarantee that Jack is a nice
guy and doesn't screw up". I'm sure he is but everybody screws up, and
in this case the patch:

- does not even *apply* to the upstream kernel, because it uses
(presumably Amazon-specific) CAP numbers above 10000

- does not work if the vCPU is moved from one physical CPU to another

- does not work if the intel_pstate driver writes to MSR_HWP_REQUEST

- does not include documentation for the new capability

- does not include a selftest

- is unacceptable anyway because, as mentioned in the cover letter, it
isn't undone when the process exits

Jack, please understand that I am not really blaming you in any way, and
ask some of your colleagues with upstream kernel experience (Alex Graf,
David Woodhouse, Filippo Sironi, Jan Schoenherr, Amit Shah are the ones
I know) which patches could be good targets for including upstream.

Paolo