linux-kernel - [PATCH 3.16 048/131] KVM/VMX: Expose SSBD properly to guests

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Message-ID: <lsq.1538257387.354890251@decadent.org.uk>
Date:   Sat, 29 Sep 2018 22:43:07 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org,
        "Konrad Rzeszutek Wilk" <konrad.wilk@...cle.com>,
        "Thomas Gleixner" <tglx@...utronix.de>, kvm@...r.kernel.org,
        "Radim Krčmář" <rkrcmar@...hat.com>,
        "Paolo Bonzini" <pbonzini@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH 3.16 048/131] KVM/VMX: Expose SSBD properly to guests

3.16.59-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>

commit 0aa48468d00959c8a37cd3ac727284f4f7359151 upstream.

The X86_FEATURE_SSBD is an synthetic CPU feature - that is
it bit location has no relevance to the real CPUID 0x7.EBX[31]
bit position. For that we need the new CPU feature name.

Fixes: 52817587e706 ("x86/cpufeatures: Disentangle SSBD enumeration")
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: kvm@...r.kernel.org
Cc: "Radim Krčmář" <rkrcmar@...hat.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Link: https://lkml.kernel.org/r/20180521215449.26423-2-konrad.wilk@oracle.com
[bwh: Backported to 3.16:
 - Fix guest_cpuid_has_spec_ctrl() as well
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -318,7 +318,7 @@ static inline int __do_cpuid_ent(struct
 
 	/* cpuid 7.0.edx*/
 	const u32 kvm_cpuid_7_0_edx_x86_features =
-		F(SPEC_CTRL) | F(SSBD) | F(ARCH_CAPABILITIES);
+		F(SPEC_CTRL) | F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES);
 
 	/* all calls to cpuid_count() should be made on the same cpu */
 	get_cpu();
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -123,7 +123,7 @@ static inline bool guest_cpuid_has_spec_
 	if (best && (best->ebx & bit(X86_FEATURE_AMD_IBRS)))
 		return true;
 	best = kvm_find_cpuid_entry(vcpu, 7, 0);
-	return best && (best->edx & (bit(X86_FEATURE_SPEC_CTRL) | bit(X86_FEATURE_SSBD)));
+	return best && (best->edx & (bit(X86_FEATURE_SPEC_CTRL) | bit(X86_FEATURE_SPEC_CTRL_SSBD)));
 }
 
 static inline bool guest_cpuid_has_arch_capabilities(struct kvm_vcpu *vcpu)