Re: [tip: x86/urgent] x86/CPU/AMD: Clear RDRAND CPUID bit on AMD family 15h/16h

[Pavel Machek]

On Fri 2019-08-23 01:10:49, tip-bot2 for Tom Lendacky wrote:
> The following commit has been merged into the x86/urgent branch of tip:
> 
> Commit-ID:     c49a0a80137c7ca7d6ced4c812c9e07a949f6f24
> Gitweb:        https://git.kernel.org/tip/c49a0a80137c7ca7d6ced4c812c9e07a949f6f24
> Author:        Tom Lendacky <thomas.lendacky@xxxxxxx>
> AuthorDate:    Mon, 19 Aug 2019 15:52:35 
> Committer:     Borislav Petkov <bp@xxxxxxx>
> CommitterDate: Mon, 19 Aug 2019 19:42:52 +02:00
> 
> x86/CPU/AMD: Clear RDRAND CPUID bit on AMD family 15h/16h
> 
> There have been reports of RDRAND issues after resuming from suspend on
> some AMD family 15h and family 16h systems. This issue stems from a BIOS
> not performing the proper steps during resume to ensure RDRAND continues
> to function properly.

There are quite a few unanswered questions here.

a) Is there/should there be CVE for this?

b) Can we perform proper steps in kernel, thus making RDRAND usable
even when BIOS is buggy?

Best regards,
									Pavel
									
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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