Re: [RESEND RFC PATCH] x86/bugs: Add "unknown" reporting for MMIO Stale Data

[Pawan Gupta]

On Sat, Jul 30, 2022 at 12:02:34AM +0200, Borislav Petkov wrote:
> On Fri, Jul 29, 2022 at 02:46:27PM -0700, Pawan Gupta wrote:
> > Let me see if there is a way to distinguish between 4. and 5. below:
> > 
> >    CPU category				  X86_BUG_MMIO_STALE_DATA	X86_BUG_MMIO_UNKNOWN
> > -----------------------------------------------------------------------------------------------
> > 1. Known affected (in cpu list)			1				0
> > 2. CPUs with HW immunity (MMIO_NO=1)		0				0
> > 3. Other vendors				0				0
> > 4. Older Intel CPUs				0				1
> > 5. Not affected current CPUs (but MMIO_NO=0)	0				?
> 
> Not affected current CPUs should be arch_cap_mmio_immune() == true, no?

That would be true in most cases, with some exceptions like systems
that did not update the microcode.