linux-kernel - [PATCH 21/26] KVM: x86: Handle RDTSCP CPUID adjustment in VMX code

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Message-Id: <20200129234640.8147-22-sean.j.christopherson@intel.com>
Date:   Wed, 29 Jan 2020 15:46:35 -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 21/26] 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/include/asm/kvm_host.h | 1 -
 arch/x86/kvm/cpuid.c            | 3 +--
 arch/x86/kvm/svm.c              | 6 ------
 arch/x86/kvm/vmx/vmx.c          | 6 ++++--
 4 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 8a685509c218..3cd11257257c 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1144,7 +1144,6 @@ struct kvm_x86_ops {
 	int (*get_tdp_level)(struct kvm_vcpu *vcpu);
 	u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
 	int (*get_lpage_level)(void);
-	bool (*rdtscp_supported)(void);
 
 	void (*set_tdp_cr3)(struct kvm_vcpu *vcpu, unsigned long cr3);
 
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index e376d648f94d..ce7f6dfcf832 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -410,7 +410,6 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, 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;
 
@@ -432,7 +431,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, 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/svm.c b/arch/x86/kvm/svm.c
index 1092d5e6c683..2adc3a474b80 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -6096,11 +6096,6 @@ static int svm_get_lpage_level(void)
 	return PT_PDPE_LEVEL;
 }
 
-static bool svm_rdtscp_supported(void)
-{
-	return boot_cpu_has(X86_FEATURE_RDTSCP);
-}
-
 static bool svm_xsaves_supported(void)
 {
 	return boot_cpu_has(X86_FEATURE_XSAVES);
@@ -7476,7 +7471,6 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
 
 	.cpuid_update = svm_cpuid_update,
 
-	.rdtscp_supported = svm_rdtscp_supported,
 	.xsaves_supported = svm_xsaves_supported,
 	.umip_emulated = svm_umip_emulated,
 	.pt_supported = svm_pt_supported,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 3845ca7da6e0..f244b2356847 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7145,6 +7145,10 @@ static void vmx_set_supported_cpuid(struct kvm_cpuid_entry2 *entry)
 		if (vmx_umip_emulated())
 			cpuid_entry_set(entry, X86_FEATURE_UMIP);
 		break;
+	case 0x80000001:
+		if (!cpu_has_vmx_rdtscp())
+			cpuid_entry_clear(entry, X86_FEATURE_RDTSCP);
+		break;
 	default:
 		break;
 	}
@@ -7884,8 +7888,6 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
 
 	.cpuid_update = vmx_cpuid_update,
 
-	.rdtscp_supported = vmx_rdtscp_supported,
-
 	.set_supported_cpuid = vmx_set_supported_cpuid,
 
 	.has_wbinvd_exit = cpu_has_vmx_wbinvd_exit,
-- 
2.24.1