From: Maxim Levitsky <mlevitsk@redhat.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>, Tao Xu <tao3.xu@intel.com>,
Jim Mattson <jmattson@google.com>,
linux-kernel@vger.kernel.org, Joerg Roedel <joro@8bytes.org>,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>, Wanpeng Li <wanpengli@tencent.com>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Jingqi Liu <jingqi.liu@intel.com>
Subject: Re: [PATCH 2/2] kvm/x86: don't expose MSR_IA32_UMWAIT_CONTROL unconditionally
Date: Wed, 27 May 2020 18:17:00 +0300 [thread overview]
Message-ID: <69386188ba90a8852525f1c984d5df57c21ee2e7.camel@redhat.com> (raw)
In-Reply-To: <20200527012140.GD31696@linux.intel.com>
On Tue, 2020-05-26 at 18:21 -0700, Sean Christopherson wrote:
> On Sat, May 23, 2020 at 07:14:55PM +0300, Maxim Levitsky wrote:
> > This msr is only available when the host supports WAITPKG feature.
> >
> > This breaks a nested guest, if the L1 hypervisor is set to ignore
> > unknown msrs, because the only other safety check that the
> > kernel does is that it attempts to read the msr and
> > rejects it if it gets an exception.
> >
> > Fixes: 6e3ba4abce KVM: vmx: Emulate MSR IA32_UMWAIT_CONTROL
>
> Same comments on the line wraps and Fixes tag.
I rewrote the commit message and I hope that the new version
is better. I fixed the 'fixes' message as well.
>
> For the code:
>
> Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Thank you!
Best regards,
Maxim Levitsky
>
> > Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> > ---
> > arch/x86/kvm/x86.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index b226fb8abe41b..4752293312947 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -5316,6 +5316,10 @@ static void kvm_init_msr_list(void)
> > min(INTEL_PMC_MAX_GENERIC,
> > x86_pmu.num_counters_gp))
> > continue;
> > break;
> > + case MSR_IA32_UMWAIT_CONTROL:
> > + if (!kvm_cpu_cap_has(X86_FEATURE_WAITPKG))
> > + continue;
> > + break;
> > default:
> > break;
> > }
> > --
> > 2.26.2
> >
next prev parent reply other threads:[~2020-05-27 15:17 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-23 16:14 [PATCH 0/2] Fix issue with not starting nesting guests on my system Maxim Levitsky
2020-05-23 16:14 ` [PATCH 1/2] kvm/x86/vmx: enable X86_FEATURE_WAITPKG in KVM capabilities Maxim Levitsky
2020-05-27 1:20 ` Sean Christopherson
2020-05-27 15:16 ` Maxim Levitsky
2020-05-23 16:14 ` [PATCH 2/2] kvm/x86: don't expose MSR_IA32_UMWAIT_CONTROL unconditionally Maxim Levitsky
2020-05-27 1:21 ` Sean Christopherson
2020-05-27 15:17 ` Maxim Levitsky [this message]
2020-05-27 1:03 ` [PATCH 0/2] Fix issue with not starting nesting guests on my system Krish Sadhukhan
2020-05-27 1:22 ` Sean Christopherson
2020-05-27 1:13 ` Sean Christopherson
2020-05-27 15:17 ` Maxim Levitsky
2020-05-27 15:17 ` Maxim Levitsky
2020-05-27 17:00 ` Paolo Bonzini
-- strict thread matches above, loose matches on Subject: below --
2020-05-20 16:07 [PATCH 0/2] Fix breakage from adding MSR_IA32_UMWAIT_CONTROL Maxim Levitsky
2020-05-20 16:07 ` [PATCH 2/2] kvm/x86: don't expose MSR_IA32_UMWAIT_CONTROL unconditionally Maxim Levitsky
2020-05-20 16:33 ` Vitaly Kuznetsov
2020-05-20 16:56 ` Maxim Levitsky
2020-05-20 17:15 ` Vitaly Kuznetsov
2020-05-20 17:39 ` Maxim Levitsky
2020-05-21 8:03 ` Xiaoyao Li
2020-05-20 21:05 ` Paolo Bonzini
2020-05-20 21:09 ` Maxim Levitsky
2020-05-21 4:33 ` Xiaoyao Li
2020-05-21 5:28 ` Tao Xu
2020-05-21 6:37 ` Xiaoyao Li
2020-05-21 6:44 ` Tao Xu
2020-05-21 8:40 ` Paolo Bonzini
2020-06-30 13:41 ` Maxim Levitsky
2020-05-21 8:24 ` Paolo Bonzini
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