Date:   Fri, 24 Feb 2023 10:52:57 -0800
From:   Josh Poimboeuf <jpoimboe@kernel.org>
To:     Kim Phillips <kim.phillips@amd.com>
Cc:     x86@kernel.org, Borislav Petkov <bp@alien8.de>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        Joao Martins <joao.m.martins@oracle.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        David Woodhouse <dwmw@amazon.co.uk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Juergen Gross <jgross@suse.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Tony Luck <tony.luck@intel.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Alexey Kardashevskiy <aik@amd.com>, kvm@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v9 7/8] x86/cpu: Support AMD Automatic IBRS
Message-ID: <20230224185257.o3mcmloei5zqu7wa@treble>
References: <20230124163319.2277355-1-kim.phillips@amd.com>
 <20230124163319.2277355-8-kim.phillips@amd.com>
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On Tue, Jan 24, 2023 at 10:33:18AM -0600, Kim Phillips wrote:
> @@ -1495,8 +1495,12 @@ static void __init spectre_v2_select_mitigation(void)
>  		pr_err(SPECTRE_V2_EIBRS_EBPF_MSG);
>  
>  	if (spectre_v2_in_ibrs_mode(mode)) {
> -		x86_spec_ctrl_base |= SPEC_CTRL_IBRS;
> -		update_spec_ctrl(x86_spec_ctrl_base);
> +		if (boot_cpu_has(X86_FEATURE_AUTOIBRS)) {
> +			msr_set_bit(MSR_EFER, _EFER_AUTOIBRS);

Doesn't this only enable it on the boot CPU?

-- 
Josh