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Date:   Mon, 30 Mar 2020 11:38:24 -0700
From:   Sean Christopherson <sean.j.christopherson@intel.com>
To:     Jim Mattson <jmattson@google.com>
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Joerg Roedel <joro@8bytes.org>, kvm list <kvm@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Ben Gardon <bgardon@google.com>,
        Junaid Shahid <junaids@google.com>,
        Liran Alon <liran.alon@oracle.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        John Haxby <john.haxby@oracle.com>,
        Miaohe Lin <linmiaohe@huawei.com>,
        Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [PATCH v3 03/37] KVM: nVMX: Invalidate all EPTP contexts when
 emulating INVEPT for L1
Message-ID: <20200330183824.GI24988@linux.intel.com>
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On Mon, Mar 23, 2020 at 05:12:04PM -0700, Jim Mattson wrote:
> On Mon, Mar 23, 2020 at 4:51 PM Paolo Bonzini <pbonzini@redhat.com> wrote:
> >
> > On 23/03/20 17:44, Sean Christopherson wrote:
> > > So I think
> > >
> > >   Fixes: 14c07ad89f4d ("x86/kvm/mmu: introduce guest_mmu")
> > >
> > > would be appropriate?
> > >
> >
> > Yes.
> 
> I think it was actually commit efebf0aaec3d ("KVM: nVMX: Do not flush
> TLB on L1<->L2 transitions if L1 uses VPID and EPT").

Hmm, commit efebf0aaec3d it only changed flushing behavior, it didn't
affect KVM's behavior with respect to refreshing unsync'd SPTE, i.e.
reloading guest_mmu.

It's somewhat of a moot point, because _technically_ there is no bug since,
at the time of this fix, KVM always flushes and reloads on nested VM-Enter.