From: Sean Christopherson <seanjc@google.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Andrew Cooper <Andrew.Cooper3@citrix.com>
Subject: [PATCH 12/16] x86/virt: Drop unnecessary check on extended CPUID level in cpu_has_svm()
Date: Thu, 1 Dec 2022 23:26:51 +0000 [thread overview]
Message-ID: <20221201232655.290720-13-seanjc@google.com> (raw)
In-Reply-To: <20221201232655.290720-1-seanjc@google.com>
Drop the explicit check on the extended CPUID level in cpu_has_svm(), the
kernel's cached CPUID info will leave the entire SVM leaf unset if said
leaf is not supported by hardware. Prior to using cached information,
the check was needed to avoid false positives due to Intel's rather crazy
CPUID behavior of returning the values of the maximum supported leaf if
the specified leaf is unsupported.
Fixes: 682a8108872f ("x86/kvm/svm: Simplify cpu_has_svm()")
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/include/asm/virtext.h | 6 ------
1 file changed, 6 deletions(-)
diff --git a/arch/x86/include/asm/virtext.h b/arch/x86/include/asm/virtext.h
index 0b373543514f..eddc0eeb836f 100644
--- a/arch/x86/include/asm/virtext.h
+++ b/arch/x86/include/asm/virtext.h
@@ -39,12 +39,6 @@ static inline int cpu_has_svm(const char **msg)
return 0;
}
- if (boot_cpu_data.extended_cpuid_level < SVM_CPUID_FUNC) {
- if (msg)
- *msg = "can't execute cpuid_8000000a";
- return 0;
- }
-
if (!boot_cpu_has(X86_FEATURE_SVM)) {
if (msg)
*msg = "svm not available";
--
2.39.0.rc0.267.gcb52ba06e7-goog
next prev parent reply other threads:[~2022-12-01 23:28 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-01 23:26 [PATCH 00/16] x86/reboot: KVM: Clean up "emergency" virt code Sean Christopherson
2022-12-01 23:26 ` [PATCH 01/16] x86/reboot: VMCLEAR active VMCSes before emergency reboot Sean Christopherson
2022-12-01 23:26 ` [PATCH 02/16] x86/reboot: Expose VMCS crash hooks if and only if KVM_INTEL is enabled Sean Christopherson
2022-12-01 23:26 ` [PATCH 03/16] x86/reboot: Harden virtualization hooks for emergency reboot Sean Christopherson
2022-12-01 23:26 ` [PATCH 04/16] x86/reboot: Assert that IRQs are disabled when turning off virtualization Sean Christopherson
2022-12-01 23:26 ` [PATCH 05/16] x86/reboot: KVM: Handle VMXOFF in KVM's reboot callback Sean Christopherson
2022-12-01 23:26 ` [PATCH 06/16] x86/reboot: KVM: Disable SVM during reboot via virt/KVM " Sean Christopherson
2022-12-01 23:26 ` [PATCH 07/16] x86/reboot: Hoist "disable virt" helpers above "emergency reboot" path Sean Christopherson
2022-12-01 23:26 ` [PATCH 08/16] x86/reboot: Disable virtualization during reboot iff callback is registered Sean Christopherson
2022-12-01 23:26 ` [PATCH 09/16] x86/virt: KVM: Open code cpu_has_vmx() in KVM VMX Sean Christopherson
2022-12-01 23:26 ` [PATCH 10/16] x86/virt: KVM: Move VMXOFF helpers into " Sean Christopherson
2022-12-01 23:26 ` [PATCH 11/16] KVM: SVM: Make KVM_AMD depend on CPU_SUP_AMD or CPU_SUP_HYGON Sean Christopherson
2022-12-01 23:26 ` Sean Christopherson [this message]
2022-12-01 23:26 ` [PATCH 13/16] x86/virt: KVM: Open code cpu_has_svm() into kvm_is_svm_supported() Sean Christopherson
2022-12-01 23:26 ` [PATCH 14/16] x86/virt: KVM: Move "disable SVM" helper into KVM SVM Sean Christopherson
2022-12-01 23:26 ` [PATCH 15/16] KVM: x86: Force kvm_rebooting=true during emergency reboot/crash Sean Christopherson
2022-12-01 23:26 ` [PATCH 16/16] KVM: SVM: Use "standard" stgi() helper when disabling SVM Sean Christopherson
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