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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>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Arnaldo Carvalho de Melo" <acme@kernel.org>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Alexander Shishkin" <alexander.shishkin@linux.intel.com>,
	"Jiri Olsa" <jolsa@redhat.com>,
	"Namhyung Kim" <namhyung@kernel.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Sean Christopherson" <sean.j.christopherson@intel.com>,
	"Vitaly Kuznetsov" <vkuznets@redhat.com>,
	"Wanpeng Li" <wanpengli@tencent.com>,
	"Jim Mattson" <jmattson@google.com>,
	"Joerg Roedel" <joro@8bytes.org>,
	"Tony Luck" <tony.luck@intel.com>,
	"Tony W Wang-oc" <TonyWWang-oc@zhaoxin.com>,
	"Shuah Khan" <shuah@kernel.org>,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	linux-edac@vger.kernel.org, linux-kselftest@vger.kernel.org,
	"Borislav Petkov" <bp@suse.de>,
	"Jarkko Sakkinen" <jarkko.sakkinen@linux.intel.com>
Subject: [PATCH v3 09/19] x86/cpu: Clear VMX feature flag if VMX is not fully enabled
Date: Mon, 18 Nov 2019 19:12:30 -0800
Message-ID: <20191119031240.7779-10-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20191119031240.7779-1-sean.j.christopherson@intel.com>

Now that the IA32_FEATURE_CONTROL MSR is guaranteed to be configured and
locked, clear the VMX capability flag if the IA32_FEATURE_CONTROL MSR is
not supported or if BIOS disabled VMX, i.e. locked IA32_FEATURE_CONTROL
and did not set the appropriate VMX enable bit.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kernel/cpu/feature_control.c | 28 ++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/feature_control.c b/arch/x86/kernel/cpu/feature_control.c
index 33c9444dda52..2bd1a9e6021a 100644
--- a/arch/x86/kernel/cpu/feature_control.c
+++ b/arch/x86/kernel/cpu/feature_control.c
@@ -5,15 +5,26 @@
 #include <asm/msr-index.h>
 #include <asm/processor.h>
 
+#undef pr_fmt
+#define pr_fmt(fmt)	"x86/cpu: " fmt
+
+#define FEAT_CTL_UNSUPPORTED_MSG "IA32_FEATURE_CONTROL MSR unsupported on VMX capable CPU, suspected hardware or hypervisor issue.\n"
+
 void init_feature_control_msr(struct cpuinfo_x86 *c)
 {
+	bool tboot = tboot_enabled();
 	u64 msr;
 
-	if (rdmsrl_safe(MSR_IA32_FEATURE_CONTROL, &msr))
+	if (rdmsrl_safe(MSR_IA32_FEATURE_CONTROL, &msr)) {
+		if (cpu_has(c, X86_FEATURE_VMX)) {
+			pr_err_once(FEAT_CTL_UNSUPPORTED_MSG);
+			clear_cpu_cap(c, X86_FEATURE_VMX);
+		}
 		return;
+	}
 
 	if (msr & FEAT_CTL_LOCKED)
-		return;
+		goto update_caps;
 
 	/*
 	 * Ignore whatever value BIOS left in the MSR to avoid enabling random
@@ -28,8 +39,19 @@ void init_feature_control_msr(struct cpuinfo_x86 *c)
 	 */
 	if (cpu_has(c, X86_FEATURE_VMX) && IS_ENABLED(CONFIG_KVM)) {
 		msr |= FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX;
-		if (tboot_enabled())
+		if (tboot)
 			msr |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX;
 	}
 	wrmsrl(MSR_IA32_FEATURE_CONTROL, msr);
+
+update_caps:
+	if (!cpu_has(c, X86_FEATURE_VMX))
+		return;
+
+	if ((tboot && !(msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX)) ||
+	    (!tboot && !(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX))) {
+		pr_err_once("VMX (%s TXT) disabled by BIOS\n",
+			    tboot ? "inside" : "outside");
+		clear_cpu_cap(c, X86_FEATURE_VMX);
+	}
 }
-- 
2.24.0


  parent reply index

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-19  3:12 [PATCH v3 00/19] x86/cpu: Clean up handling of VMX features Sean Christopherson
2019-11-19  3:12 ` [PATCH v3 01/19] x86/msr-index: Clean up bit defines for IA32_FEATURE_CONTROL MSR Sean Christopherson
2019-11-19 11:15   ` Borislav Petkov
2019-11-19 23:18     ` Sean Christopherson
2019-11-20 17:48       ` Borislav Petkov
2019-11-21  9:46   ` Jarkko Sakkinen
2019-11-21 22:14     ` Sean Christopherson
2019-11-29 21:06       ` Jarkko Sakkinen
2019-11-29 21:11         ` Jarkko Sakkinen
2019-11-19  3:12 ` [PATCH v3 02/19] selftests: kvm: Replace manual MSR defs with common msr-index.h Sean Christopherson
2019-11-19  3:12 ` [PATCH v3 03/19] tools arch x86: Sync msr-index.h from kernel sources Sean Christopherson
2019-11-19  3:12 ` [PATCH v3 04/19] x86/intel: Initialize IA32_FEATURE_CONTROL MSR at boot Sean Christopherson
2019-11-19  4:41   ` Kai Huang
2019-11-19  5:03     ` Sean Christopherson
2019-11-21 10:39   ` Jarkko Sakkinen
2019-11-21 10:41     ` Jarkko Sakkinen
2019-11-21 11:05       ` Borislav Petkov
2019-11-21 22:12         ` Sean Christopherson
2019-11-22 12:34           ` Borislav Petkov
2019-11-19  3:12 ` [PATCH v3 05/19] x86/mce: WARN once if IA32_FEATURE_CONTROL MSR is left unlocked Sean Christopherson
2019-11-21 10:45   ` Jarkko Sakkinen
2019-11-19  3:12 ` [PATCH v3 06/19] x86/centaur: Use common IA32_FEATURE_CONTROL MSR initialization Sean Christopherson
2019-11-19  3:12 ` [PATCH v3 07/19] x86/zhaoxin: " Sean Christopherson
2019-11-19  3:12 ` [PATCH v3 08/19] KVM: VMX: Drop initialization of IA32_FEATURE_CONTROL MSR Sean Christopherson
2019-11-19  3:12 ` Sean Christopherson [this message]
2019-11-19  3:12 ` [PATCH v3 10/19] KVM: VMX: Use VMX feature flag to query BIOS enabling Sean Christopherson
2019-11-19  3:12 ` [PATCH v3 11/19] KVM: VMX: Check for full VMX support when verifying CPU compatibility Sean Christopherson
2019-11-19  3:12 ` [PATCH v3 12/19] x86/vmx: Introduce VMX_FEATURES_* Sean Christopherson
2019-11-21 16:52   ` Borislav Petkov
2019-11-21 21:50     ` Sean Christopherson
2019-11-22 18:36       ` Borislav Petkov
2019-11-22 19:09         ` Sean Christopherson
2019-11-19  3:12 ` [PATCH v3 13/19] x86/cpu: Detect VMX features on Intel, Centaur and Zhaoxin CPUs Sean Christopherson
2019-11-19  3:12 ` [PATCH v3 14/19] x86/cpu: Print VMX flags in /proc/cpuinfo using VMX_FEATURES_* Sean Christopherson
2019-11-19  3:12 ` [PATCH v3 15/19] x86/cpufeatures: Drop synthetic VMX feature flags Sean Christopherson
2019-11-19  3:12 ` [PATCH v3 16/19] KVM: VMX: Use VMX_FEATURE_* flags to define VMCS control bits Sean Christopherson
2019-11-19  3:12 ` [PATCH v3 17/19] x86/cpufeatures: Clean up synthetic virtualization flags Sean Christopherson
2019-11-19  3:12 ` [PATCH v3 18/19] perf/x86: Provide stubs of KVM helpers for non-Intel CPUs Sean Christopherson
2019-11-19  3:12 ` [PATCH v3 19/19] KVM: VMX: Allow KVM_INTEL when building for Centaur and/or Zhaoxin CPUs Sean Christopherson

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