<story><title>CacheOut: Leaking Data on Intel CPUs via Cache Evictions</title><url>https://cacheoutattack.com/</url></story><parent_chain><item><author>kohtatsu</author><text>Did AMD design their processors with these side channel attacks in mind, or is it a matter of where the security research is focused?</text></item></parent_chain><comment><author>makomk</author><text>Mostly, it seems to be a difference in design philosphy - AMD processors prevent speculative reads of data that shouldn&amp;#x27;t be accessible almost everywhere, whereas Intel ones allow them pretty much everywhere. This particular attack requires TSX which AMD processors don&amp;#x27;t have, but I don&amp;#x27;t think it&amp;#x27;d work on AMD processors anyway because they&amp;#x27;re not missing the security check that Intel ones are. If I remember rightly, there were other now-mitigated exploits for this line fill buffer leak that didn&amp;#x27;t require TSX.&lt;p&gt;(The one exception is also interesting. AMD processors allow speculative reads past the end of x86 segments and past BOUND instructions, which of course no-one uses these days. This suggests there may have been a deliberate decision to block them in the more important cases.)</text></comment>
<story><title>CacheOut: Leaking Data on Intel CPUs via Cache Evictions</title><url>https://cacheoutattack.com/</url></story><parent_chain><item><author>kohtatsu</author><text>Did AMD design their processors with these side channel attacks in mind, or is it a matter of where the security research is focused?</text></item></parent_chain><comment><author>Symmetry</author><text>In this case AMD just doesn&amp;#x27;t support TSX instructions.  For previous vulnerabilities with Meltdown I&amp;#x27;d guess that AMD just didn&amp;#x27;t feel they had the engineering resources to do after the fact validation of memory access permissions without architecturally leaking data in some weird corner case.  But then along comes Meltdown and it turns out that non-architectural leaks are a thing that can happen and if you try to do after the fact validation you can&amp;#x27;t prevent them.</text></comment>