From: Jacob Keller <jacob.e.keller@intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: TonyWWang-oc@zhaoxin.com, acme@kernel.org,
alexander.shishkin@linux.intel.com, bp@alien8.de, bp@suse.de,
hpa@zytor.com, jacob.jun.pan@linux.intel.com,
jarkko.sakkinen@linux.intel.com, jmattson@google.com,
jolsa@redhat.com, joro@8bytes.org, kvm@vger.kernel.org,
lenb@kernel.org, linux-edac@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-pm@vger.kernel.org, mark.rutland@arm.com, mingo@redhat.com,
namhyung@kernel.org, pbonzini@redhat.com, peterz@infradead.org,
rkrcmar@redhat.com, shuah@kernel.org, tglx@linutronix.de,
tony.luck@intel.com, vkuznets@redhat.com, wanpengli@tencent.com,
x86@kernel.org
Subject: Re: [PATCH v5 13/19] x86/cpufeatures: Add flag to track whether MSR IA32_FEAT_CTL is configured
Date: Tue, 25 Feb 2020 15:54:34 -0800 [thread overview]
Message-ID: <5434303a-0742-3811-fd14-6445d296c0f0@intel.com> (raw)
In-Reply-To: <20200225232900.GO9245@linux.intel.com>
On 2/25/2020 3:29 PM, Sean Christopherson wrote:
> On Tue, Feb 25, 2020 at 02:52:32PM -0800, Jacob Keller wrote:
>> On 2/25/2020 2:12 PM, Sean Christopherson wrote:
>>> On Tue, Feb 25, 2020 at 01:49:13PM -0800, Jacob Keller wrote:
>>>> Hi Sean,
>>>>
>>>> I suspect something is wrong and the features are enabled even though
>>>> the BIOS has it disabled, leading to later failure because of this.
>>>
>>> Hrm. On the failing kernel, what are the values of MSR 0x3a for all CPUs,
>>> i.e. what's the output of 'sudo rdmsr -a 0x3a'?
>>>
>>
>> On the old (fedora 30) kernel, every cpu reports as '1'.
>>
>> I can't easily test the failing kernel because it crashes during boot.
>
> No need, your BIOS is likely locking the MSR, I doubt the value is any
> different when running the new kernel.
>
> Does reverting commit a4d0b2fdbcf7 ("KVM: VMX: Use VMX feature flag to
> query BIOS enabling") resolve the issue?
>
> Is the failing kernel an (umodified) upstream kernel? A stable kernel?
> Or something else? Assuming it's an unmodified upstream kernel, can you
> send your .config? I've tried all the obvious Kconfig combinations but
> haven't been able to reproduce the problem. Staring at the code hasn't
> yielded any revelations either.
>
I reverted the suggested commit and added some prints:
[ 26.056398] X86_FEATURE_MSR_IA32_FEAT_CTL is enabled
[ 26.062426] X86_FEATURE_VMX is enabled
[ 26.066923] kvm: disabled by bios
So the old code flow is finding KVM to be disabled, but both features
are set...
The code that sets this is run first:
> Feb 25 15:46:05 jbrandeb-saw1 kernel: x86/cpu: FEAT_CTL_LOCKED is set
> Feb 25 15:46:05 jbrandeb-saw1 kernel: x86/cpu: FEAT_CTL_VMX_ENABLED_INSIDE_SMX is unset
> Feb 25 15:46:05 jbrandeb-saw1 kernel: x86/cpu: FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX is unset
> Feb 25 15:46:05 jbrandeb-saw1 kernel: x86/cpu: MSR locked by bios
> Feb 25 15:46:05 jbrandeb-saw1 kernel: x86/cpu: VMX (outside TXT) disabled by BIOS
> Feb 25 15:46:05 jbrandeb-saw1 kernel: x86/cpu: disabling X86_FEATURE_VMX
But somehow... it is still set later...
So there's something weird going on. Maybe "boot_cpu_has" in the
vmx_disabled_by_bios is wrong? Hmm.
next prev parent reply other threads:[~2020-02-25 23:54 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-21 4:44 [PATCH v5 00/19] x86/cpu: Clean up handling of VMX features Sean Christopherson
2019-12-21 4:44 ` [PATCH v5 01/19] x86/msr-index: Clean up bit defines for IA32_FEATURE_CONTROL MSR Sean Christopherson
2019-12-21 4:44 ` [PATCH v5 02/19] selftests: kvm: Replace manual MSR defs with common msr-index.h Sean Christopherson
2019-12-21 4:44 ` [PATCH v5 03/19] tools arch x86: Sync msr-index.h from kernel sources Sean Christopherson
2019-12-21 4:44 ` [PATCH v5 04/19] x86/intel: Initialize IA32_FEAT_CTL MSR at boot Sean Christopherson
2019-12-21 4:44 ` [PATCH v5 05/19] x86/mce: WARN once if IA32_FEAT_CTL MSR is left unlocked Sean Christopherson
2019-12-21 4:45 ` [PATCH v5 06/19] x86/centaur: Use common IA32_FEAT_CTL MSR initialization Sean Christopherson
2019-12-21 4:45 ` [PATCH v5 07/19] x86/zhaoxin: " Sean Christopherson
2019-12-21 4:45 ` [PATCH v5 08/19] x86/cpu: Clear VMX feature flag if VMX is not fully enabled Sean Christopherson
2019-12-21 4:45 ` [PATCH v5 09/19] x86/vmx: Introduce VMX_FEATURES_* Sean Christopherson
2019-12-21 4:45 ` [PATCH v5 10/19] x86/cpu: Detect VMX features on Intel, Centaur and Zhaoxin CPUs Sean Christopherson
2019-12-21 4:45 ` [PATCH v5 11/19] x86/cpu: Print VMX flags in /proc/cpuinfo using VMX_FEATURES_* Sean Christopherson
2019-12-21 4:45 ` [PATCH v5 12/19] x86/cpu: Set synthetic VMX cpufeatures during init_ia32_feat_ctl() Sean Christopherson
2019-12-21 4:45 ` [PATCH v5 13/19] x86/cpufeatures: Add flag to track whether MSR IA32_FEAT_CTL is configured Sean Christopherson
2020-02-25 21:49 ` Jacob Keller
2020-02-25 22:12 ` Sean Christopherson
2020-02-25 22:52 ` Jacob Keller
2020-02-25 23:29 ` Sean Christopherson
2020-02-25 23:54 ` Jacob Keller [this message]
2020-02-26 0:41 ` Jacob Keller
2020-02-26 0:42 ` Sean Christopherson
2020-02-26 0:58 ` Jacob Keller
2020-02-26 20:41 ` Jacob Keller
2020-02-26 20:57 ` Sean Christopherson
2020-02-26 21:03 ` Jacob Keller
2020-02-26 21:25 ` Sean Christopherson
2020-02-26 21:53 ` Jacob Keller
2020-02-27 2:12 ` Sean Christopherson
2020-02-27 4:20 ` Huang, Kai
2020-02-27 18:09 ` Jacob Keller
2019-12-21 4:45 ` [PATCH v5 14/19] KVM: VMX: Drop initialization of IA32_FEAT_CTL MSR Sean Christopherson
2019-12-21 4:45 ` [PATCH v5 15/19] KVM: VMX: Use VMX feature flag to query BIOS enabling Sean Christopherson
2019-12-21 4:45 ` [PATCH v5 16/19] KVM: VMX: Check for full VMX support when verifying CPU compatibility Sean Christopherson
2019-12-21 4:45 ` [PATCH v5 17/19] KVM: VMX: Use VMX_FEATURE_* flags to define VMCS control bits Sean Christopherson
2020-01-13 18:32 ` Borislav Petkov
2020-01-13 18:37 ` Sean Christopherson
2020-01-13 18:38 ` Borislav Petkov
2020-01-13 18:42 ` Sean Christopherson
2020-01-13 18:52 ` [PATCH] KVM: VMX: Rename define to CPU_BASED_USE_TSC_OFFSETTING Borislav Petkov
2020-01-13 20:16 ` Sean Christopherson
2020-01-14 9:31 ` Borislav Petkov
2020-01-14 17:27 ` Sean Christopherson
2019-12-21 4:45 ` [PATCH v5 18/19] perf/x86: Provide stubs of KVM helpers for non-Intel CPUs Sean Christopherson
2019-12-21 4:45 ` [PATCH v5 19/19] KVM: VMX: Allow KVM_INTEL when building for Centaur and/or Zhaoxin CPUs Sean Christopherson
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