Messages in this thread | | | Subject | Re: [RFC][PATCH] x86: proposed new ARCH_CAPABILITIES MSR bit for RSB-underflow | From | Arjan van de Ven <> | Date | Fri, 16 Feb 2018 11:47:27 -0800 |
| |
On 2/16/2018 11:43 AM, Linus Torvalds wrote: > On Fri, Feb 16, 2018 at 11:38 AM, Linus Torvalds > <torvalds@linux-foundation.org> wrote: >> >> Of course, your patch still doesn't allow for "we claim to be skylake >> for various other independent reasons, but the RSB issue is fixed". > > .. maybe nobody ever has a reason to do that, though?
yeah I would be extremely surprised > > Who knows, virtualization people may simply want the user to specify > the model, but then make the Spectre decisions be based on actual > hardware capabilities (whether those are "current" or "some minimum > base").
once you fake to be skylake when you're not, you do that for a reason; normallyt that reason is that you COULD migrate to a skylake. (and migration is not supposed to be visble to the guest OS)
and at that point you are a skylake for all intents and purposes.
(and the virtualization people also really hate it when the hardware burst the bubble of this fakeing hardware to be not what it is)
| |