Messages in this thread | | | Date | Thu, 9 May 2024 11:21:44 +0300 | Subject | Re: [PATCH v5 3/3] x86/bugs: Add 'spectre_bhi=vmexit' cmdline option | From | Nikolay Borisov <> |
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On 9.05.24 г. 8:24 ч., Josh Poimboeuf wrote: > On Wed, May 08, 2024 at 06:10:21PM +0300, Nikolay Borisov wrote: >>> @@ -1659,19 +1662,22 @@ static void __init bhi_select_mitigation(void) >>> return; >>> } >>> + /* Mitigate in hardware if supported */ >>> if (spec_ctrl_bhi_dis()) >>> return; >>> if (!IS_ENABLED(CONFIG_X86_64)) >>> return; >>> - /* Mitigate KVM by default */ >>> - setup_force_cpu_cap(X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT); >>> - pr_info("Spectre BHI mitigation: SW BHB clearing on vm exit\n"); >>> + if (bhi_mitigation == BHI_MITIGATION_VMEXIT_ONLY) { >>> + pr_info("Spectre BHI mitigation: SW BHB clearing on vm exit only\n"); >>> + setup_force_cpu_cap(X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT); >>> + return; >>> + } >> >> nit: How about setting CLEAR_BHB_LOOP_ON_VMEXIT unconditionally, then >> afterwards checking if MITIGATION_VMEXIT_ONLY is set and if yes simply >> return, that way you don't duplicate the setup of the VMEXIT code > > I think the duplication actually makes it more readable. In both cases > it puts the setting of the features together along with the > corresponding pr_info().
Right, my suggestion also meant that setting + pr info will be together, unconditional and if MITIGATION_VMEXIT_ONLY is set we return early, without setting X86_FEATURE_CLEAR_BHB_LOOP. In any case it's a minor remark, feel free to ignore.
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
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