Re: [PATCH 0/2] x86/rdrand: implement sanity check for RDSEED

[Mikhail Paulyshka]

On 3/12/25 3:40 PM, Borislav Petkov wrote:
> On Wed, Mar 12, 2025 at 03:31:28PM +0300, Mikhail Paulyshka wrote:
> > On the AMD Cyan Skillfish (Family 0x17 Model 0x47 Stepping 0x0), which
> > is a Zen2-based APU found on the AMD BC-250 board, there is a situation
> > where RDRAND works fine, but RDSEED generates FF. This leads to some
> > applications that use RDSEED to generate random numbers (such as
> > Qt and KDE) into a nearly unusable state.
> >
> > Although AMD has fixed the Zen2 RDRAND issues in 2019 with a microcode update,
> > no such update has been released for the Family 0x17 Model 0x47 core.
> What's the microcode level on that machine?
> dmesg | grep -i microcode [ 0.059689] [ T0] Zenbleed: please update your microcode for the most 
optimal fix [ 0.663746] [ T1] microcode: Current revision: 0x08407007
> Also, send
>
> cpuid -r

https://paste.debian.net/1362645