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: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Andrew Cooper <Andrew.Cooper3@citrix.com>,
Kai Huang <kai.huang@intel.com>, Chao Gao <chao.gao@intel.com>
Subject: [PATCH v4 12/19] x86/virt: Drop unnecessary check on extended CPUID level in cpu_has_svm()
Date: Fri, 21 Jul 2023 13:18:52 -0700 [thread overview]
Message-ID: <20230721201859.2307736-13-seanjc@google.com> (raw)
In-Reply-To: <20230721201859.2307736-1-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 a27801f2bc71..be50c414efe4 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";
--
2.41.0.487.g6d72f3e995-goog
next prev parent reply other threads:[~2023-07-21 20:20 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-21 20:18 [PATCH v4 00/19] x86/reboot: KVM: Clean up "emergency" virt code Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 01/19] x86/reboot: VMCLEAR active VMCSes before emergency reboot Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 02/19] x86/reboot: Harden virtualization hooks for " Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 03/19] x86/reboot: KVM: Handle VMXOFF in KVM's reboot callback Sean Christopherson
2023-07-24 23:57 ` Huang, Kai
2023-07-21 20:18 ` [PATCH v4 04/19] x86/reboot: KVM: Disable SVM during reboot via virt/KVM " Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 05/19] x86/reboot: Assert that IRQs are disabled when turning off virtualization Sean Christopherson
2023-07-24 21:19 ` Peter Zijlstra
2023-07-24 21:41 ` Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 06/19] x86/reboot: Hoist "disable virt" helpers above "emergency reboot" path Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 07/19] x86/reboot: Disable virtualization during reboot iff callback is registered Sean Christopherson
2023-07-24 23:57 ` Huang, Kai
2023-07-21 20:18 ` [PATCH v4 08/19] x86/reboot: Expose VMCS crash hooks if and only if KVM_{INTEL,AMD} is enabled Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 09/19] x86/virt: KVM: Open code cpu_has_vmx() in KVM VMX Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 10/19] x86/virt: KVM: Move VMXOFF helpers into " Sean Christopherson
2023-07-28 9:08 ` Xu Yilun
2023-07-28 9:43 ` Huang, Kai
2023-07-21 20:18 ` [PATCH v4 11/19] KVM: SVM: Make KVM_AMD depend on CPU_SUP_AMD or CPU_SUP_HYGON Sean Christopherson
2023-07-21 20:18 ` Sean Christopherson [this message]
2023-07-21 20:18 ` [PATCH v4 13/19] x86/virt: KVM: Open code cpu_has_svm() into kvm_is_svm_supported() Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 14/19] KVM: SVM: Check that the current CPU supports SVM in kvm_is_svm_supported() Sean Christopherson
2023-07-24 21:21 ` Peter Zijlstra
2023-07-24 21:40 ` Sean Christopherson
2023-07-25 9:16 ` Peter Zijlstra
2023-07-27 16:39 ` Sean Christopherson
2023-07-24 22:29 ` Dmitry Torokhov
2023-07-24 23:53 ` Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 15/19] KVM: VMX: Ensure CPU is stable when probing basic VMX support Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 16/19] x86/virt: KVM: Move "disable SVM" helper into KVM SVM Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 17/19] KVM: x86: Force kvm_rebooting=true during emergency reboot/crash Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 18/19] KVM: SVM: Use "standard" stgi() helper when disabling SVM Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 19/19] KVM: VMX: Skip VMCLEAR logic during emergency reboots if CR4.VMXE=0 Sean Christopherson
2023-07-25 3:51 ` Huang, Kai
2023-07-25 18:15 ` Sean Christopherson
2023-07-25 22:20 ` Huang, Kai
2023-08-04 0:40 ` [PATCH v4 00/19] x86/reboot: KVM: Clean up "emergency" virt code Sean Christopherson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230721201859.2307736-13-seanjc@google.com \
--to=seanjc@google.com \
--cc=Andrew.Cooper3@citrix.com \
--cc=bp@alien8.de \
--cc=chao.gao@intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=kai.huang@intel.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®