Re: [PATCH] x86/its: use Sapphire Rapids+ feature to opt out

[Dave Hansen]

On 10/21/25 07:39, Jon Kohler wrote:
> For BHI_CTRL, depending on what QEMU the VM was originally *started* on,
> the guest may have access to Sapphire Rapids models, but BHI_CTRL may
> not have existed in the QEMU source at that time, as those were introduced
> into two different timeframes.

I have two solutions for you here, and neither of them involves patching
the kernel.

First, I personally volunteer to travel to your customers' homes to
provide in-person education with my "education stick" about why updating
software is important.

Second, if they continue to be education-resistant, I offer to
personally travel to the datacenters where these VMs are running to
inspect the racks where they run and brainstorm solutions. A warning,
though: I am quite clumsy and I've been known to bump into power cables
and circuit breakers.