From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>,
Borislav Petkov <bp@alien8.de>
Cc: "Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, "Radim Krčmář" <rkrcmar@redhat.com>,
"Vitaly Kuznetsov" <vkuznets@redhat.com>,
"Wanpeng Li" <wanpengli@tencent.com>,
"Jim Mattson" <jmattson@google.com>,
kvm@vger.kernel.org
Subject: Re: [PATCH v2 06/16] x86/cpu: Clear VMX feature flag if VMX is not fully enabled
Date: Fri, 15 Nov 2019 11:05:24 +0100 [thread overview]
Message-ID: <5aacaba0-76e2-9824-ebd4-fa510bce712d@redhat.com> (raw)
In-Reply-To: <20191114183238.GH24045@linux.intel.com>
On 14/11/19 19:32, Sean Christopherson wrote:
>>> + pr_err_once("x86/cpu: VMX disabled, IA32_FEATURE_CONTROL MSR unsupported\n");
>
> My thought for having the print was to alert the user that something is
> royally borked with their system. There's nothing the user can do to fix
> it per se, but it does indicate that either their hardware or the VMM
> hosting their virtual machine is broken. So maybe be more explicit about
> it being a likely hardware/VMM issue?
Yes, good idea.
>>> +update_caps:
>>> + if (!cpu_has(c, X86_FEATURE_VMX))
>>> + return;
>>
>> If this test is just so we can save us the below code, I'd say remove it
>> for the sake of having less code in that function. The test is cheap and
>> not on a fast path so who cares if we clear an alrady cleared bit. But
>> maybe this evolves in the later patches...
>
> I didn't want to print the "VMX disabled by BIOS..." message if VMX isn't
> supported in the first place. Later patches also add more code in this
> flow, but avoiding the print message is the main motiviation.
I agree on this too.
Paolo
>>> +
>>> + if ((tboot && !(msr & FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX)) ||
>>> + (!tboot && !(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX))) {
>>> + pr_err_once("x86/cpu: VMX disabled by BIOS (TXT %s)\n",
>>> + tboot ? "enabled" : "disabled");
>>> + clear_cpu_cap(c, X86_FEATURE_VMX);
>>> + }
>>> }
>>
>> --
>> Regards/Gruss,
>> Boris.
>>
>> https://people.kernel.org/tglx/notes-about-netiquette
>
next prev parent reply other threads:[~2019-11-15 10:05 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 ` [PATCH v2 05/16] KVM: VMX: Drop initialization of IA32_FEATURE_CONTROL MSR Sean Christopherson
2019-10-22 10:51 ` 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 [this message]
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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