From: Sean Christopherson <seanjc@google.com>
To: Oliver Upton <oupton@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Jim Mattson <jmattson@google.com>,
kvm@vger.kernel.org, Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Joerg Roedel <joro@8bytes.org>, David Dunn <daviddunn@google.com>
Subject: Re: [PATCH v4 1/8] KVM: nVMX: Keep KVM updates to BNDCFGS ctrl bits across MSR write
Date: Thu, 7 Apr 2022 00:34:00 +0000 [thread overview]
Message-ID: <Yk4xd4hAij3ZQame@google.com> (raw)
In-Reply-To: <CAOQ_Qsj6KwV_OjDS-JwOkPs76Z9FiCBVBTGgp-_hZHQ6BAeExg@mail.gmail.com>
On Wed, Apr 06, 2022, Oliver Upton wrote:
> Hey Sean,
>
> On Wed, Apr 6, 2022 at 5:26 PM Sean Christopherson <seanjc@google.com> wrote:
> >
> > On Fri, Mar 04, 2022, Paolo Bonzini wrote:
> > > On 3/4/22 00:44, Sean Christopherson wrote:
> > > >
> > > > diff --git a/arch/x86/kvm/vmx/nested.h b/arch/x86/kvm/vmx/nested.h
> > > > index c92cea0b8ccc..46dd1967ec08 100644
> > > > --- a/arch/x86/kvm/vmx/nested.h
> > > > +++ b/arch/x86/kvm/vmx/nested.h
> > > > @@ -285,8 +285,8 @@ static inline bool nested_cr4_valid(struct kvm_vcpu *vcpu, unsigned long val)
> > > > }
> > > >
> > > > /* No difference in the restrictions on guest and host CR4 in VMX operation. */
> > > > -#define nested_guest_cr4_valid nested_cr4_valid
> > > > -#define nested_host_cr4_valid nested_cr4_valid
> > > > +#define nested_guest_cr4_valid kvm_is_valid_cr4
> > > > +#define nested_host_cr4_valid kvm_is_valid_cr4
> > >
> > > This doesn't allow the theoretically possible case of L0 setting some
> > > CR4-fixed-0 bits for L1. I'll send another one.
> >
> > Are you still planning on sending a proper patch for this?
> >
> > And more importantly, have we shifted your view on this patch/series?
>
> Sorry, I should've followed up. If nobody else complains, let's just
> leave everything as-is and avoid repeating the mistakes of the patches
> to blame (hey, I authored one of those!)
The problem is that if we leave things as is, someone will inevitably think it's
the right thing to do and will repeat those mistakes. I don't see why we wouldn't
add the quirk, broken userspace gets to keep its broken behavior unless it opts
into to disabling the quirk.
next prev parent reply other threads:[~2022-04-07 0:34 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-01 6:03 [PATCH v4 0/8] KVM: x86: VMX ctrl MSR + KVM quirk fixes Oliver Upton
2022-03-01 6:03 ` [PATCH v4 1/8] KVM: nVMX: Keep KVM updates to BNDCFGS ctrl bits across MSR write Oliver Upton
2022-03-01 18:00 ` Paolo Bonzini
2022-03-01 18:43 ` Oliver Upton
2022-03-02 12:21 ` Paolo Bonzini
2022-03-02 20:51 ` Oliver Upton
2022-03-02 21:22 ` Paolo Bonzini
2022-03-02 21:54 ` Oliver Upton
2022-03-03 1:43 ` Sean Christopherson
2022-03-03 6:29 ` Paolo Bonzini
2022-03-03 16:15 ` Sean Christopherson
2022-03-03 21:44 ` Jim Mattson
2022-03-03 23:44 ` Sean Christopherson
2022-03-04 15:50 ` Paolo Bonzini
2022-04-07 0:26 ` Sean Christopherson
2022-04-07 0:29 ` Oliver Upton
2022-04-07 0:32 ` Oliver Upton
2022-04-07 0:34 ` Sean Christopherson [this message]
2022-05-27 16:55 ` Sean Christopherson
2022-03-01 6:03 ` [PATCH v4 2/8] KVM: nVMX: Keep KVM updates to PERF_GLOBAL_CTRL " Oliver Upton
2022-03-01 18:01 ` Paolo Bonzini
2022-04-07 0:21 ` Sean Christopherson
2022-03-01 6:03 ` [PATCH v4 3/8] KVM: nVMX: Drop nested_vmx_pmu_refresh() Oliver Upton
2022-03-01 6:03 ` [PATCH v4 4/8] KVM: x86: Introduce KVM_CAP_DISABLE_QUIRKS2 Oliver Upton
2022-03-09 16:01 ` Paolo Bonzini
2022-03-01 6:03 ` [PATCH v4 5/8] KVM: nVMX: Add a quirk for KVM tweaks to VMX control MSRs Oliver Upton
2022-04-07 0:28 ` Sean Christopherson
2022-03-01 6:03 ` [PATCH v4 6/8] selftests: KVM: Separate static alloc from KVM_GET_SUPPORTED_CPUID call Oliver Upton
2022-03-01 6:03 ` [PATCH v4 7/8] selftests: KVM: Add test for PERF_GLOBAL_CTRL VMX control MSR bits Oliver Upton
2022-03-01 16:59 ` David Dunn
2022-03-01 6:03 ` [PATCH v4 8/8] selftests: KVM: Add test for BNDCFGS " Oliver Upton
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