Re: [PATCH v2 4/8] x86/spec_ctrl: Add sysctl knobs to enable/disable SPEC_CTRL feature

From: Peter Zijlstra
Date: Mon Jan 08 2018 - 10:08:18 EST


On Fri, Jan 05, 2018 at 06:12:19PM -0800, Tim Chen wrote:
> +void scan_spec_ctrl_feature(struct cpuinfo_x86 *c)
> +{
> + if ((!c->cpu_index) && (boot_cpu_has(X86_FEATURE_SPEC_CTRL))) {

We should test X86_BUG_SPECTRE_V1 here too before default enabling this,
no?

> + if (!ibrs_admin_disabled) {
> + dynamic_ibrs = 1;
> + ibrs_enabled = IBRS_ENABLED;
> + }
> + }
> +}