Re: [PATCH 2/2] x86/speculation: Support "Enhanced IBRS" on future CPUs

[Linus Torvalds]

On Mon, Feb 19, 2018 at 4:13 PM, Alan Cox <gnomes@xxxxxxxxxxxxxxxxxxx> wrote:
>
> In theory there's nothing stopping a guest getting a 'you are about to
> gain/lose IBRS' message or having a new 'CPU' hotplugged and the old one
> removed.

I'm not convinced we handle the case of hotplug CPU's with different
CPU models correctly.

In fact, I'd be very surprised it it worked in the general case.

            Linus