linux-kernel - [PATCH v4 3/7] x86/cpu: Make X86_FEATURE_LFENCE

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Message-ID: <20221201015003.295769-4-kim.phillips@amd.com>
Date:   Wed, 30 Nov 2022 19:49:59 -0600
From:   Kim Phillips <kim.phillips@....com>
To:     <x86@...nel.org>
CC:     Kim Phillips <kim.phillips@....com>,
        Babu Moger <Babu.Moger@....com>,
        Borislav Petkov <bp@...en8.de>, Borislav Petkov <bp@...e.de>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
        Joao Martins <joao.m.martins@...cle.com>,
        Jonathan Corbet <corbet@....net>,
        "Konrad Rzeszutek Wilk" <konrad.wilk@...cle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        David Woodhouse <dwmw@...zon.co.uk>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Juergen Gross <jgross@...e.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Tony Luck <tony.luck@...el.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Alexey Kardashevskiy <aik@....com>, <kvm@...r.kernel.org>,
        <linux-doc@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v4 3/7] x86/cpu: Make X86_FEATURE_LFENCE_RDTSC a scattered feature bit

It's a part of the CPUID 0x80000021 leaf, and this allows us to
group this and other CPUID 0x80000021 EAX feature bits to being
propagated via kvm_set_cpu_caps() instead of open-coding them in
__do_cpuid_func().

Unlike the other CPUID 0x80000021 EAX feature bits,
X86_FEATURE_LFENCE_RDTSC already had an entry in cpufeatures.h.

Signed-off-by: Kim Phillips <kim.phillips@....com>
---
 arch/x86/kernel/cpu/scattered.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
index d0734cc19d37..caa03466cd9e 100644
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -46,6 +46,7 @@ static const struct cpuid_bit cpuid_bits[] = {
 	{ X86_FEATURE_PROC_FEEDBACK,    CPUID_EDX, 11, 0x80000007, 0 },
 	{ X86_FEATURE_MBA,		CPUID_EBX,  6, 0x80000008, 0 },
 	{ X86_FEATURE_NO_NESTED_DATA_BP,CPUID_EAX,  0, 0x80000021, 0 },
+	{ X86_FEATURE_LFENCE_RDTSC,	CPUID_EAX,  2, 0x80000021, 0 },
 	{ X86_FEATURE_NULL_SEL_CLR_BASE,CPUID_EAX,  6, 0x80000021, 0 },
 	{ X86_FEATURE_PERFMON_V2,	CPUID_EAX,  0, 0x80000022, 0 },
 	{ X86_FEATURE_AMD_LBR_V2,	CPUID_EAX,  1, 0x80000022, 0 },
-- 
2.34.1