Messages in this thread Patch in this message | | | Date | Sat, 12 Aug 2023 20:30:09 +0200 | From | Borislav Petkov <> | Subject | Re: [RFC][PATCH 05/17] x86/cpu: Cleanup the untrain mess |
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On Wed, Aug 09, 2023 at 03:26:35PM +0200, Peter Zijlstra wrote: > I think simply setting UNRET for SRSO at this point will be sufficient. > That ensures the entry_untrain_ret thing gets called, and the > alternative there DTRT. > > The feature isn't used anywhere else afaict. > > Then later, after the fancy alternatives happen, this can be cleaned up > again.
Yes, this fixes it for >= Zen3:
--- diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 4b0a770fbacb..611d048f6415 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -2448,6 +2448,7 @@ static void __init srso_select_mitigation(void) * like ftrace, static_call, etc. */ setup_force_cpu_cap(X86_FEATURE_RETHUNK); + setup_force_cpu_cap(X86_FEATURE_UNRET); if (boot_cpu_data.x86 == 0x19) { setup_force_cpu_cap(X86_FEATURE_SRSO_ALIAS); -- Regards/Gruss, Boris.
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