From: Paolo Bonzini <pbonzini@redhat.com>
To: "Sean Christopherson" <sean.j.christopherson@intel.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
x86@kernel.org, "Peter Zijlstra" <peterz@infradead.org>,
"Arnaldo Carvalho de Melo" <acme@kernel.org>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Tony Luck" <tony.luck@intel.com>,
"Tony W Wang-oc" <TonyWWang-oc@zhaoxin.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
linux-edac@vger.kernel.org, Borislav Petkov <bp@suse.de>,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Subject: Re: [PATCH 01/16] x86/intel: Initialize IA32_FEATURE_CONTROL MSR at boot
Date: Mon, 7 Oct 2019 19:05:32 +0200 [thread overview]
Message-ID: <afd37a28-d135-7c34-bd63-7c11099998bc@redhat.com> (raw)
In-Reply-To: <20191004215615.5479-2-sean.j.christopherson@intel.com>
On 04/10/19 23:56, Sean Christopherson wrote:
> Always lock IA32_FEATURE_CONTROL if it exists, even if the CPU doesn't
> support VMX, so that other existing and future kernel code that queries
> IA32_FEATURE_CONTROL can assume it's locked.
Possibly stupid question: why bother locking it? It makes sense to lock
the MSR bits to _off_ in the firmware, but if the BIOS hasn't locked it,
why should the OS?
It seems to me that locking introduces a lot of complication.
Paolo
next prev parent reply other threads:[~2019-10-07 17:05 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-04 21:55 [PATCH 00/16] x86/cpu: Clean up handling of VMX features Sean Christopherson
2019-10-04 21:56 ` [PATCH 01/16] x86/intel: Initialize IA32_FEATURE_CONTROL MSR at boot Sean Christopherson
2019-10-07 17:05 ` Paolo Bonzini [this message]
2019-10-07 17:10 ` Sean Christopherson
2019-10-04 21:56 ` [PATCH 02/16] x86/mce: WARN once if IA32_FEATURE_CONTROL MSR is left unlocked Sean Christopherson
2019-10-04 21:56 ` [PATCH 03/16] x86/centaur: Use common IA32_FEATURE_CONTROL MSR initialization Sean Christopherson
2019-10-04 21:56 ` [PATCH 04/16] x86/zhaoxin: " Sean Christopherson
2019-10-04 21:56 ` [PATCH 05/16] KVM: VMX: Drop initialization of IA32_FEATURE_CONTROL MSR Sean Christopherson
2019-10-04 23:24 ` Jim Mattson
2019-10-04 21:56 ` [PATCH 06/16] x86/cpu: Clear VMX feature flag if VMX is not fully enabled Sean Christopherson
2019-10-04 21:56 ` [PATCH 07/16] KVM: VMX: Use VMX feature flag to query BIOS enabling Sean Christopherson
2019-10-04 23:26 ` Jim Mattson
2019-10-04 21:56 ` [PATCH 08/16] KVM: VMX: Check for full VMX support when verifying CPU compatibility Sean Christopherson
2019-10-04 23:35 ` Jim Mattson
2019-10-04 21:56 ` [PATCH 09/16] x86/vmx: Introduce VMX_FEATURES_* Sean Christopherson
2019-10-07 17:08 ` Paolo Bonzini
2019-10-07 17:13 ` Sean Christopherson
2019-10-04 21:56 ` [PATCH 10/16] x86/cpu: Detect VMX features on Intel, Centaur and Zhaoxin CPUs Sean Christopherson
2019-10-07 17:11 ` Paolo Bonzini
2019-10-07 19:54 ` Sean Christopherson
2019-10-08 6:55 ` Paolo Bonzini
2019-10-04 21:56 ` [PATCH 11/16] x86/cpu: Print VMX features as separate line item in /proc/cpuinfo Sean Christopherson
2019-10-07 17:12 ` Paolo Bonzini
2019-10-07 19:56 ` Sean Christopherson
2019-10-08 6:57 ` Paolo Bonzini
2019-10-08 16:53 ` Jim Mattson
2019-10-09 19:16 ` Sean Christopherson
2019-10-09 21:13 ` Paolo Bonzini
2019-10-04 21:56 ` [PATCH 12/16] x86/cpufeatures: Drop synthetic VMX feature flags Sean Christopherson
2019-10-04 21:56 ` [PATCH 13/16] KVM: VMX: Use VMX_FEATURE_* flags to define VMCS control bits Sean Christopherson
2019-10-04 21:56 ` [PATCH 14/16] x86/cpufeatures: Clean up synthetic virtualization flags Sean Christopherson
2019-10-04 21:56 ` [PATCH 15/16] perf/x86: Provide stubs of KVM helpers for non-Intel CPUs Sean Christopherson
2019-10-04 21:56 ` [PATCH 16/16] KVM: VMX: Allow KVM_INTEL when building for Centaur and/or Zhaoxin CPUs Sean Christopherson
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