linux-kernel - [PATCH 34/61] KVM: x86: Handle RDTSCP CPUID adjustment in VMX code

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Date:   Sat,  1 Feb 2020 10:51:51 -0800
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 34/61] KVM: x86: Handle RDTSCP CPUID adjustment in VMX code

Move the clearing of the RDTSCP CPUID bit into VMX, which has a separate
VMCS control to enable RDTSCP in non-root, to eliminate an instance of
the undesirable "unsigned f_* = *_supported ? F(*) : 0" pattern in the
common CPUID handling code.  Drop ->rdtscp_supported() since CPUID
adjustment was the last remaining user.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/cpuid.c   | 3 +--
 arch/x86/kvm/vmx/vmx.c | 4 ++++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index a1f46b3ca16e..fc507270f3f3 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -424,7 +424,6 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 	unsigned f_gbpages = 0;
 	unsigned f_lm = 0;
 #endif
-	unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
 	unsigned f_xsaves = kvm_x86_ops->xsaves_supported() ? F(XSAVES) : 0;
 	unsigned f_intel_pt = kvm_x86_ops->pt_supported() ? F(INTEL_PT) : 0;
 
@@ -446,7 +445,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
 		F(PAT) | F(PSE36) | 0 /* Reserved */ |
 		f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
-		F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp |
+		F(FXSR) | F(FXSR_OPT) | f_gbpages | F(RDTSCP) |
 		0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
 	/* cpuid 1.ecx */
 	const u32 kvm_cpuid_1_ecx_x86_features =
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index a9728cc0c343..3990ba691d07 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7119,6 +7119,10 @@ static void vmx_set_supported_cpuid(struct kvm_cpuid_entry2 *entry)
 		    boot_cpu_has(X86_FEATURE_OSPKE))
 			cpuid_entry_set(entry, X86_FEATURE_PKU);
 		break;
+	case 0x80000001:
+		if (!cpu_has_vmx_rdtscp())
+			cpuid_entry_clear(entry, X86_FEATURE_RDTSCP);
+		break;
 	default:
 		break;
 	}
-- 
2.24.1