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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	linux-kernel@vger.kernel.org,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Vitaly Kuznetsov" <vkuznets@redhat.com>,
	"Wanpeng Li" <wanpengli@tencent.com>,
	"Jim Mattson" <jmattson@google.com>,
	kvm@vger.kernel.org,
	"Sean Christopherson" <sean.j.christopherson@intel.com>
Subject: [PATCH v2 05/16] KVM: VMX: Drop initialization of IA32_FEATURE_CONTROL MSR
Date: Mon, 21 Oct 2019 17:08:20 -0700	[thread overview]
Message-ID: <20191022000820.1854-1-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20191021234632.32363-1-sean.j.christopherson@intel.com>

Remove the code to initialize IA32_FEATURE_CONTROL MSR when KVM is
loaded now that the MSR is initialized during boot on all CPUs that
support VMX, i.e. can possibly load kvm_intel.

Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/vmx/vmx.c | 48 +++++++++++++++++-------------------------
 1 file changed, 19 insertions(+), 29 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index d4575ffb3cec..23c9e4b91b31 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2192,24 +2192,26 @@ static __init int vmx_disabled_by_bios(void)
 	u64 msr;
 
 	rdmsrl(MSR_IA32_FEATURE_CONTROL, msr);
-	if (msr & FEATURE_CONTROL_LOCKED) {
-		/* launched w/ TXT and VMX disabled */
-		if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX)
-			&& tboot_enabled())
-			return 1;
-		/* launched w/o TXT and VMX only enabled w/ TXT */
-		if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX)
-			&& (msr & FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX)
-			&& !tboot_enabled()) {
-			printk(KERN_WARNING "kvm: disable TXT in the BIOS or "
-				"activate TXT before enabling KVM\n");
-			return 1;
-		}
-		/* launched w/o TXT and VMX disabled */
-		if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX)
-			&& !tboot_enabled())
-			return 1;
+
+	if (WARN_ON_ONCE(!(msr & FEATURE_CONTROL_LOCKED)))
+		return 1;
+
+	/* launched w/ TXT and VMX disabled */
+	if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX) &&
+	    tboot_enabled())
+		return 1;
+	/* launched w/o TXT and VMX only enabled w/ TXT */
+	if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX) &&
+	    (msr & FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX) &&
+	    !tboot_enabled()) {
+		pr_warn("kvm: disable TXT in the BIOS or "
+			"activate TXT before enabling KVM\n");
+		return 1;
 	}
+	/* launched w/o TXT and VMX disabled */
+	if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX) &&
+	    !tboot_enabled())
+		return 1;
 
 	return 0;
 }
@@ -2226,7 +2228,6 @@ static int hardware_enable(void)
 {
 	int cpu = raw_smp_processor_id();
 	u64 phys_addr = __pa(per_cpu(vmxarea, cpu));
-	u64 old, test_bits;
 
 	if (cr4_read_shadow() & X86_CR4_VMXE)
 		return -EBUSY;
@@ -2254,17 +2255,6 @@ static int hardware_enable(void)
 	 */
 	crash_enable_local_vmclear(cpu);
 
-	rdmsrl(MSR_IA32_FEATURE_CONTROL, old);
-
-	test_bits = FEATURE_CONTROL_LOCKED;
-	test_bits |= FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX;
-	if (tboot_enabled())
-		test_bits |= FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX;
-
-	if ((old & test_bits) != test_bits) {
-		/* enable and lock */
-		wrmsrl(MSR_IA32_FEATURE_CONTROL, old | test_bits);
-	}
 	kvm_cpu_vmxon(phys_addr);
 	if (enable_ept)
 		ept_sync_global();
-- 
2.22.0


  parent reply	other threads:[~2019-10-22  0:08 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-21 23:46 [PATCH v2 00/16] x86/cpu: Clean up handling of VMX features Sean Christopherson
2019-10-21 23:54 ` [PATCH v2 01/16] x86/intel: Initialize IA32_FEATURE_CONTROL MSR at boot Sean Christopherson
2019-10-22  0:15   ` Sean Christopherson
2019-10-25 14:09   ` Borislav Petkov
2019-10-25 15:11     ` Sean Christopherson
2019-10-21 23:56 ` [PATCH v2 02/16] x86/mce: WARN once if IA32_FEATURE_CONTROL MSR is left unlocked Sean Christopherson
2019-10-25 14:22   ` Borislav Petkov
2019-10-22  0:08 ` [PATCH v2 03/16] x86/centaur: Use common IA32_FEATURE_CONTROL MSR initialization Sean Christopherson
2019-10-22  0:08 ` [PATCH v2 04/16] x86/zhaoxin: " Sean Christopherson
2019-10-22  0:08 ` Sean Christopherson [this message]
2019-10-22 10:51   ` [PATCH v2 05/16] KVM: VMX: Drop initialization of IA32_FEATURE_CONTROL MSR Paolo Bonzini
2019-10-22 15:16     ` Sean Christopherson
2019-11-14 18:34       ` Sean Christopherson
2019-11-15 10:10         ` Paolo Bonzini
2019-10-25 16:26   ` Borislav Petkov
2019-10-25 16:39     ` Borislav Petkov
2019-10-22  0:08 ` [PATCH v2 06/16] x86/cpu: Clear VMX feature flag if VMX is not fully enabled Sean Christopherson
2019-10-25 16:38   ` Borislav Petkov
2019-11-14 18:32     ` Sean Christopherson
2019-11-15 10:05       ` Paolo Bonzini
2019-11-15 10:34         ` Borislav Petkov
2019-11-15 15:34           ` Sean Christopherson
2019-11-15 15:39             ` Borislav Petkov
2019-10-22  0:08 ` [PATCH v2 07/16] KVM: VMX: Use VMX feature flag to query BIOS enabling Sean Christopherson
2019-10-22  0:08 ` [PATCH v2 08/16] KVM: VMX: Check for full VMX support when verifying CPU compatibility Sean Christopherson
2019-10-22  0:08 ` [PATCH v2 09/16] x86/vmx: Introduce VMX_FEATURES_* Sean Christopherson
2019-10-22  0:08 ` [PATCH v2 10/16] x86/cpu: Detect VMX features on Intel, Centaur and Zhaoxin CPUs Sean Christopherson
2019-10-22  0:08 ` [PATCH v2 11/16] x86/cpu: Print VMX flags in /proc/cpuinfo using VMX_FEATURES_* Sean Christopherson
2019-10-22  0:08 ` [PATCH v2 12/16] x86/cpufeatures: Drop synthetic VMX feature flags Sean Christopherson
2019-10-22  0:08 ` [PATCH v2 13/16] KVM: VMX: Use VMX_FEATURE_* flags to define VMCS control bits Sean Christopherson
2019-10-22  0:09 ` [PATCH v2 14/16] x86/cpufeatures: Clean up synthetic virtualization flags Sean Christopherson
2019-10-22  0:12 ` [PATCH v2 15/16] perf/x86: Provide stubs of KVM helpers for non-Intel CPUs Sean Christopherson
2019-10-22  0:12 ` [PATCH v2 16/16] KVM: VMX: Allow KVM_INTEL when building for Centaur and/or Zhaoxin CPUs Sean Christopherson

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