techspot AMD admits that Zen 3 CPUs are vulnerable to a new Spectre-style attack

[UltraMega]

Quote

In a recently published whitepaper, titled "Security Analysis of AMD Predictive Store Forwarding," AMD describes the nature of the vulnerability and discusses the associated complications. In simple terms, the implementation of Predictive Store Forwarding (PSF) reopens the lines of attack previously threatened by Spectre v1, v2, and v4, because of its speculative nature.

https://www.techspot.com/news/89173-amd-admits-zen-3-cpus-vulnerable-new-spectre.html

 

According to people who understand this much better than I do, though I guess it's similar to spectre in how it works, it's something that can only occur in more specific and rare scenarios. 

[tictoc]

Link to the white paper: https://www.amd.com/system/files/documents/security-analysis-predictive-store-forwarding.pdf

 

This is similar to Spectre v4.  Unfortunate that this vulnerability exists, but not too surprising since CPU design is done so far out in front of release.  On the plus side it is somewhat refreshing that it was AMD that disclosed the vulnerability.

[ENTERPRISE]

Nice to see AMD's transparency with this. One more only hopes any forthcoming patches do not nerf performance.

[J7SC_Orion]

7 hours ago, ENTERPRISE said:

Nice to see AMD's transparency with this. One more only hopes any forthcoming patches do not nerf performance.

 

...yeah, AMD seems to handle the communication abut this well. FYI, apparently, Phoronix is planning a performance impact analysis of certain bits in the affected predictive branches being turned off, or at least 'nerfed'...

 

 

 

Edited April 6, 2021 by J7SC_Orion

[Sir Beregond]

Disappointing, but appreciate AMD being forthcoming with this one.

[tictoc]

1 hour ago, ENTERPRISE said:

Nice to see AMD's transparency with this. One more only hopes any forthcoming patches do not nerf performance.

 

59 minutes ago, J7SC_Orion said:

 

...yeah, AMD seems to handle the communication abut this well. FYI, apparently, Phornonix is planning a performance impact analysis of certain bits in the affected predictive branches being turned off, or at least 'nerfed'...

 

Some preliminary testing was done over the weekend, with a custom kernel on Linux, that disabled PSF.  Performance hit is pretty much 0, at least for the workloads that were tested.  https://www.phoronix.com/scan.php?page=article&item=amd-zen3-psf&num=1

 

[ENTERPRISE]

2 hours ago, tictoc said:

 

 

Some preliminary testing was done over the weekend, with a custom kernel on Linux, that disabled PSF.  Performance hit is pretty much 0, at least for the workloads that were tested.  https://www.phoronix.com/scan.php?page=article&item=amd-zen3-psf&num=1

 

Nice ! Good to see that so far the performance hit will be negligible.