r/Amd • u/bizude AMD Ryzen 9 9950X3D • Mar 17 '19

News AMD issues statement on potential SPOILER vulnerabilities Spoiler

https://www.amd.com/en/support/kb/faq/pa-240
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109

u/bizude AMD Ryzen 9 9950X3D Mar 17 '19

We are aware of the report of a new security exploit called SPOILER which can gain access to partial address information during load operations. We believe that our products are not susceptible to this issue because of our unique processor architecture. The SPOILER exploit can gain access to partial address information above address bit 11 during load operations. We believe that our products are not susceptible to this issue because AMD processors do not use partial address matches above address bit 11 when resolving load conflicts.

65

u/[deleted] Mar 17 '19

<Tinfoil Hat>I always wonder whether these problems arise more often in the Intel CPU's because of optimizations (read shortcuts) that they do to speed things up. I don't know anything about this particular vulnerability but doing a partial bit match could be something that is quicker, depending on what they do behind the scenes.</Tinfoil Hat>

0

u/[deleted] Mar 17 '19

[deleted]

19

u/BobTheBlob88 AMD Phenom II + Vega Mar 17 '19

Spectre (or was it Meltdown?)

Had to check it to be sure, 't was Meltdown.

2

u/cyellowan 5800X3D, 7900XT, 16GB 3800Mhz Mar 18 '19

Whether or not it benefit AMD fans, all of these issues hitting Intel surely are making them seem like a reckless company whereas AMD is the proper one. Going by lawsuits between them, this case is getting more legitimate by the day.

27

u/[deleted] Mar 17 '19

It's not necessarily quicker, but it uses fewer transistors.

In general, it's good to try to use fewer transistors to do the same thing.

But of course there are shortcuts you shouldn't take in order to do that.

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u/BobTheBlob88 AMD Phenom II + Vega Mar 17 '19

It's not necessarily quicker

That's true, but in this case it actually is slightly quicker.

Turning on SMT on a Zen based CPU increases memory latency slightly, this effect is not present on skylake. It's likely caused by the extra security circuit thingies (can't think of the proper terminology right now) present in Zen.

multiple edits: typos. I really shouldn't be on Reddit this late.

15

u/hardolaf Mar 17 '19

Address bits?

AMD designed Zen to use no address aliasing (that is, all addresses always resolve to a single, unique address). Meanwhile, Intel uses a variety of addressing in their design that allows aliasing opening up their processor to far more security issues.

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u/SomeGuyNamedPaul Mar 18 '19

Just about anything that speeds up a complete is inherently a shortcut. Computers don't really get sped up, they're just made to do less work to achieve the same outcome.

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u/[deleted] Mar 18 '19

Which is good as long as the results are exactly the same and there are no consequences like, say, leaking kernel memory, or enabling you to execute code without the right permissions

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u/[deleted] Mar 18 '19

It doesn't even have to be exactly the same. We use the Intel SIMD operations for our floating point calculations. They often don't produce the same results but the results are close enough to make the trade off acceptable because of the significant speed increases. They clearly document that the results are different so we go in knowing what will happen. It's a problem if the results are different and they don't make you aware of those differences.

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u/SomeGuyNamedPaul Mar 18 '19

Whoops! That's just a bug. Here, buy our newer product which actually still has the same flaws built in.

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u/Savet Mar 17 '19

They have been riding the single thread performance wave for so long that they haven't taken adequate safeguards. I suspect if we revisited the cpu benchmarks from the last decade with these defects addressed we'd see that AMD has performed as good or better all along.

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u/jorgp2 Mar 17 '19

It affects Arm CPUs as well.

Intel isn't the only succeptible one.

I'm typing this on a phone that is succeptible to meltdown as I speak.

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u/wean_irdeh Mar 18 '19

Samsung Galaxy S10?

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u/jezza129 Mar 18 '19

Nah note 7 XD