linux-kernel - [PATCH 3/3] KVM: x86: use Intel speculation bugs and features as derived in generic x86 code

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Message-Id: <1566376002-17121-4-git-send-email-pbonzini@redhat.com>
Date:   Wed, 21 Aug 2019 10:26:42 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     jmattson@...hat.com, ehabkost@...hat.com, konrad.wilk@...cle.com
Subject: [PATCH 3/3] KVM: x86: use Intel speculation bugs and features as derived in generic x86 code

Similar to AMD bits, set the Intel bits from the vendor-independent
feature and bug flags, because KVM_GET_SUPPORTED_CPUID does not care
about the vendor and they should be set on AMD processors as well.

Suggested-by: Jim Mattson <jmattson@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/cpuid.c | 6 ++++++
 arch/x86/kvm/x86.c   | 7 +++++++
 2 files changed, 13 insertions(+)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 43caeb6059b9..dd5985eb61b4 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -392,6 +392,12 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry, int index)
 
 		entry->edx &= kvm_cpuid_7_0_edx_x86_features;
 		cpuid_mask(&entry->edx, CPUID_7_EDX);
+		if (boot_cpu_has(X86_FEATURE_IBPB) && boot_cpu_has(X86_FEATURE_IBRS))
+			entry->edx |= F(SPEC_CTRL);
+		if (boot_cpu_has(X86_FEATURE_STIBP))
+			entry->edx |= F(INTEL_STIBP);
+		if (boot_cpu_has(X86_FEATURE_SSBD))
+			entry->edx |= F(SPEC_CTRL_SSBD);
 		/*
 		 * We emulate ARCH_CAPABILITIES in software even
 		 * if the host doesn't support it.
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 93b0bd45ac73..6b81c7609d09 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1254,6 +1254,13 @@ static u64 kvm_get_arch_capabilities(void)
 	if (l1tf_vmx_mitigation != VMENTER_L1D_FLUSH_NEVER)
 		data |= ARCH_CAP_SKIP_VMENTRY_L1DFLUSH;
 
+	if (!boot_cpu_has_bug(X86_BUG_CPU_MELTDOWN))
+		data |= ARCH_CAP_RDCL_NO;
+	if (!boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS))
+		data |= ARCH_CAP_SSB_NO;
+	if (!boot_cpu_has_bug(X86_BUG_MDS))
+		data |= ARCH_CAP_MDS_NO;
+
 	return data;
 }
 
-- 
1.8.3.1