On Tue Jul 25, 2023 at 1:27 AM UTC, Jonathan Gray wrote: On Mon, Jul 24, 2023 at 01:41:36PM -0400, Marc Deslauriers wrote: Hi,
There seems to be confusion regarding which is the correct commit:
Your blog post says it's 0bc3126c9cfa0b8c761483215c25382f831a7c6f which is for family 17h.
This post says it's b250b32ab1d044953af2dc5e790819a7703b7ee6 which is for family 19h.
I assume the 17h family one is the correct one?
Thanks,
Marc. Yes, but it by no means covers all zen 2 models. See amd-ucode/README
Family=0x17 Model=0x31 Stepping=0x00: Patch=0x0830107a Length=3200 bytes Family=0x17 Model=0xa0 Stepping=0x00: Patch=0x08a00008 Length=3200 bytes
17-31-00 Rome/Castle Peak 0x0830107a 17-a0-00 Mendocino 0x08a00008
Models missing include:
17-60-01 Renoir 0x0860010b 17-68-01 Lucienne 0x08608105 17-71-00 Matisse 0x08701032 17-90-02 Van Gogh
The known good patch levels are used by xen and linux. But the microcode for Renoir, Lucienne and Matisse is not available as far as I can tell. the amd security bulletin at https://www.amd.com/en/resources/product-security/bulletin/amd-sb-7008.html states that really only 2nd-gen epyc is fixed. etas for all other cpus (consumer level) are in october/november/december.
quoting above: 2nd Gen AMD EPYC™ Processors "Rome" (fixed) AMD Ryzen 3000 Series Desktop Processors "Matisse" (Target Dec 2023) AMD Ryzen 4000 Series Desktop Processors with Radeon Graphics "Renoir" AM4 (Target Dec 2023) AMD Ryzen Threadripper 3000 Series Processors "Castle Peak" HEDT (Target Oct 2023) AMD Ryzen Threadripper PRO 3000WX Series Processors "Castle Peak" WS SP3 (Target Nov 2023/Dec 2023) AMD Ryzen 5000 Series Mobile Processors with Radeon Graphics "Lucienne" (Target Dec 2023) AMD Ryzen 4000 Series Mobile Processors with Radeon Graphics "Renoir" (Target Nov 2023) AMD Ryzen 7020 Series Processors "Mendocino" FT6 (Target Dec 2023)
this is a disaster of a security announcement from AMD. nothing is fixed except for epyc. the only workaround anyone really has is the chicken bit, thankfully.
A timing and power-based side channel attack leveraging the x86 PREFETCH instructions on some AMD CPUs could potentially result in leaked kernel address space information.