[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen stable-4.16] x86/AMD: extend Zenbleed check to models "good" ucode isn't known for
commit 08539e8315fdae5f5bfd655d53ed35fd2922fe6c Author: Jan Beulich <jbeulich@xxxxxxxx> AuthorDate: Wed Aug 23 09:26:36 2023 +0200 Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> CommitDate: Tue Sep 19 19:38:04 2023 +0100 x86/AMD: extend Zenbleed check to models "good" ucode isn't known for Reportedly the AMD Custom APU 0405 found on SteamDeck, models 0x90 and 0x91, (quoting the respective Linux commit) is similarly affected. Put another instance of our Zen1 vs Zen2 distinction checks in amd_check_zenbleed(), forcing use of the chickenbit irrespective of ucode version (building upon real hardware never surfacing a version of 0xffffffff). Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> (cherry picked from commit 145a69c0944ac70cfcf9d247c85dee9e99d9d302) --- xen/arch/x86/cpu/amd.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/xen/arch/x86/cpu/amd.c b/xen/arch/x86/cpu/amd.c index 60c6d88edf..a591038757 100644 --- a/xen/arch/x86/cpu/amd.c +++ b/xen/arch/x86/cpu/amd.c @@ -800,10 +800,17 @@ void amd_check_zenbleed(void) case 0xa0 ... 0xaf: good_rev = 0x08a00008; break; default: /* - * With the Fam17h check above, parts getting here are Zen1. - * They're not affected. + * With the Fam17h check above, most parts getting here are + * Zen1. They're not affected. Assume Zen2 ones making it + * here are affected regardless of microcode version. + * + * Zen1 vs Zen2 isn't a simple model number comparison, so use + * STIBP as a heuristic to distinguish. */ - return; + if (!boot_cpu_has(X86_FEATURE_AMD_STIBP)) + return; + good_rev = ~0U; + break; } rdmsrl(MSR_AMD64_DE_CFG, val); -- generated by git-patchbot for /home/xen/git/xen.git#stable-4.16
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