Massive security hole in CPU's incoming?Official Meltdown/Spectre Discussion Thread

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rainy

Senior member
Jul 17, 2013
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I can hardly imagine that Intel could do anything better for Epyc sales./s

Btw, have they more surprises in their bag?
 
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Jan Olšan

Senior member
Jan 12, 2017
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If Ian Cutress is reading this...
https://twitter.com/IanCutress/status/948452457667022849
"Some published academic workarounds and patch methods give a 0.3% perf hit on average."

The 0.27% was the hit cited by the original research from academics. The final code in Linux is different and its main author stated that he doesn't find the low number representative, it's more like 10x that in general tasks (of course, it looks to be worse in syscall-heavy stuff). I think he states that somewhere in the LKML discussion but I can't find the exact message now (I saw it when writing about it yesterday and forgot to bookmark...).

But in any case, the "0,3 %" is for the research, not for the actual implementation. It might have been measured on CPU heavy code like encoding (I didn't read the paper).
 

BigDaveX

Senior member
Jun 12, 2014
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You know, part of me wonders whether maybe, just maybe Intel were so desperate in the mid-2000s, what with AMD consistently slaughtering their product line-up across the board (or at least matching it, where Turion and Pentium M/Core 1 were concerned), that they deliberately compromised the security and data integrity of their chips in an attempt to get any sort of advantage over AMD.

Okay, that's probably not what actually happened... but it'd be funny as hell if Intel needlessly compromised their chips in an effort to defeat K10 and Bulldozer, only for it to come back and bite them just when AMD happens to have a very strong competitor on the market.
 
Feb 27, 2014
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You know, part of me wonders whether maybe, just maybe Intel were so desperate in the mid-2000s, what with AMD consistently slaughtering their product line-up across the board (or at least matching it, where Turion and Pentium M/Core 1 were concerned), that they deliberately compromised the security and data integrity of their chips in an attempt to get any sort of advantage over AMD.

Okay, that's probably not what actually happened... but it'd be funny as hell if Intel needlessly compromised their chips in an effort to defeat K10 and Bulldozer, only for it to come back and bite them just when AMD happens to have a very strong competitor on the market.

I was thinking the same...
 

realibrad

Lifer
Oct 18, 2013
12,337
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You know, part of me wonders whether maybe, just maybe Intel were so desperate in the mid-2000s, what with AMD consistently slaughtering their product line-up across the board (or at least matching it, where Turion and Pentium M/Core 1 were concerned), that they deliberately compromised the security and data integrity of their chips in an attempt to get any sort of advantage over AMD.

Okay, that's probably not what actually happened... but it'd be funny as hell if Intel needlessly compromised their chips in an effort to defeat K10 and Bulldozer, only for it to come back and bite them just when AMD happens to have a very strong competitor on the market.

I doubt it because if they knew about it, they would have fixed it at some point because it would hurt given the massive lead they took after Core.
 

crazylocha

Member
Jun 21, 2010
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bauerbrazil2014 and BigDaveX,
How long ago did AMD incorporate the MMU into their silicon? From both the Phoronix and the register articles, the MMU doesn't seem to be affected. Bulldozer? Or since Zen?
 

BigDaveX

Senior member
Jun 12, 2014
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bauerbrazil2014 and BigDaveX,
How long ago did AMD incorporate the MMU into their silicon? From both the Phoronix and the register articles, the MMU doesn't seem to be affected. Bulldozer? Or since Zen?

Even earlier than that, if memory serves; I seem to recall that it was introduced in some form with K10.
 
May 11, 2008
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bauerbrazil2014 and BigDaveX,
How long ago did AMD incorporate the MMU into their silicon? From both the Phoronix and the register articles, the MMU doesn't seem to be affected. Bulldozer? Or since Zen?

Piledriver, k10 and bobcat are affected.
 

Stuka87

Diamond Member
Dec 10, 2010
6,240
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I guess the question if ryzen is vulnerable or not comes from not being on the list of 22 tested machines ?

Timestamp of list :
https://youtu.be/ewe3-mUku94?t=1763

AMD is not effected because they use a different implementation.

AMD processors are not subject to the types of attacks that the kernel page table isolation feature protects against. The AMD microarchitecture does not allow memory references, including speculative references, that access higher privileged data when running in a lesser privileged mode when that access would result in a page fault.
-Tom Lendacky
AMD
 
May 11, 2008
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zinfamous

No Lifer
Jul 12, 2006
110,629
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So, is Intel actually refusing to fix the bug, instead requesting an OS-based patch that affects AMD performance as well?

shady af if true...not that I can't understand the desperation there.
 
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Stuka87

Diamond Member
Dec 10, 2010
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So, is Intel actually refusing to fix the bug, instead requesting an OS-based patch that affects AMD performance as well?

shady af if true...not that I can't understand the desperation there.

Intel would have to replace every single CPU with ones that have a fix. There is no way to patch the CPU with a fix.
 
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Stuka87

Diamond Member
Dec 10, 2010
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That is strange because the guys from the 34c3 video tested their attack on piledriver, k10 and bobcat architecture and their exploits works on those models.
But ryzen is not tested.

If you are referencing the video noted above, thats a different issue. That video goes into detail on cache attacks. That is not related to this Intel bug.
 

zinfamous

No Lifer
Jul 12, 2006
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Intel would have to replace every single CPU with ones that have a fix. There is no way to patch the CPU with a fix.

yeah, that makes sense. One can honestly see how Intel has no other choice but to demand an OS workaround, but this certainly won't sit well outside of the US with European vendors and EU laws that are consumer protection-based.

Interesting to see how vendors respond, seeing TR offering no such security issue, no performance hit (outside of broad OS patch), and at least 3 years of hardware support that won't require the annual Intel replacement for updated chips.
 

french toast

Senior member
Feb 22, 2017
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Does not seem like a problem for general desktop users.
It's enterprise that is going to be affected.
I hope intel does not get it's way and force the fix on AMD CPUs.
Intel's problem and intel should pay the price.
 
May 11, 2008
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If you are referencing the video noted above, thats a different issue. That video goes into detail on cache attacks. That is not related to this Intel bug.

It all seems to be about accessing page tables which happen through the mmu and the translation look aside buffer and page tables in main memory.
This is about that.
https://lwn.net/Articles/569635/
Do you have detailed information about this Intel bug ?
It seems i have missed something when reading your post.
 

dark zero

Platinum Member
Jun 2, 2015
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Actually I think that Ryzen is totally secure. It has a new uARCH. And the newer Cats processors (excluding Bobcat) were slow due the security measures. So... Maybe that infamous monocore AMD E1 2100 despite being slower than a Pentium III was at least secure?

But I see the Bulldozer and the STARS uarch being hit hard with this. I fear that those guys will be on the same boat of Intel.

BTW.... I wonder if VIA proccesors are affected by this..
 

zinfamous

No Lifer
Jul 12, 2006
110,629
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So if it's correct what I saw in this? thread, that this very same flaw was publicly demonstrated at some conference in 2016, and would likely therefore be known by large hacker groups for perhaps sometime before that and certainly after, could this be tied to some of the more recent data hacks, like Equifax and others?

I'm not too familiar with how those breaches occurred, but was wondering if some these $$billion screw-ups lead back to a *potentially known* flaw in Intel's architecture, if these companies will start going after Intel for compensation.

...I'm also concerned that this design was an active decision to introduce false performance metrics to remain competitive against their more secure rival, for a decade and more. That would be extremely troubling.