Re: [PATCH] x86/speculation: Add document to describe Spectre and its mitigations

[Arjan van de Ven]

On 1/14/2019 5:06 AM, Jiri Kosina wrote:
> On Mon, 14 Jan 2019, Pavel Machek wrote:
>
> > Frankly I'd not call it Meltdown, as it works only on data in the cache,
> > so the defense is completely different. Seems more like a l1tf
> > :-).
>
> Meltdown on x86 also seems to work only for data in L1D, but the pipeline
> could be constructed in a way that data are actually fetched into L1D
> before speculation gives up, which is not the case on ppc (speculation
> aborts on L2->L1 propagation IIRC). That's why flushing L1D on ppc is
> sufficient, but on x86 it's not.

assuming L1D is not shared between SMT threads obviously :)

>