Messages in this thread | | | Subject | Re: [PATCH] x86/speculation: Add document to describe Spectre and its mitigations | From | Arjan van de Ven <> | Date | Mon, 14 Jan 2019 06:39:33 -0800 |
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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 :)
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