linux-kernel - Re: [PATCH v3 00/11] KVM: VMX: Clean up Hyper-V PV TLB flush

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Message-ID: <YD6KUoZGE2UASLa5@google.com>
Date:   Tue, 2 Mar 2021 10:56:18 -0800
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 00/11] KVM: VMX: Clean up Hyper-V PV TLB flush

On Wed, Jan 27, 2021, Paolo Bonzini wrote:
> On 27/10/20 22:23, Sean Christopherson wrote:
> > Clean up KVM's PV TLB flushing when running with EPT on Hyper-V, i.e. as
> > a nested VMM.  No real goal in mind other than the sole patch in v1, which
> > is a minor change to avoid a future mixup when TDX also wants to define
> > .remote_flush_tlb.  Everything else is opportunistic clean up.
> > 
> > Patch 1 legitimately tested on VMX (no SVM), everything else effectively
> > build tested only.
> > 
> > v3:
> >    - Add a patch to pass the root_hpa instead of pgd to vmx_load_mmu_pgd()
> >      and retrieve the active PCID only when necessary.  [Vitaly]
> >    - Selectively collects reviews (skipped a few due to changes). [Vitaly]
> >    - Explicitly invalidate hv_tlb_eptp instead of leaving it valid when
> >      the mismatch tracker "knows" it's invalid. [Vitaly]
> >    - Change the last patch to use "hv_root_ept" instead of "hv_tlb_pgd"
> >      to better reflect what is actually being tracked.
> > 
> > v2: Rewrite everything.
> > Sean Christopherson (11):
> >    KVM: x86: Get active PCID only when writing a CR3 value
> >    KVM: VMX: Track common EPTP for Hyper-V's paravirt TLB flush
> >    KVM: VMX: Stash kvm_vmx in a local variable for Hyper-V paravirt TLB
> >      flush
> >    KVM: VMX: Fold Hyper-V EPTP checking into it's only caller
> >    KVM: VMX: Do Hyper-V TLB flush iff vCPU's EPTP hasn't been flushed
> >    KVM: VMX: Invalidate hv_tlb_eptp to denote an EPTP mismatch
> >    KVM: VMX: Don't invalidate hv_tlb_eptp if the new EPTP matches
> >    KVM: VMX: Explicitly check for hv_remote_flush_tlb when loading pgd
> >    KVM: VMX: Define Hyper-V paravirt TLB flush fields iff Hyper-V is
> >      enabled
> >    KVM: VMX: Skip additional Hyper-V TLB EPTP flushes if one fails
> >    KVM: VMX: Track root HPA instead of EPTP for paravirt Hyper-V TLB
> >      flush
> > 
> >   arch/x86/include/asm/kvm_host.h |   4 +-
> >   arch/x86/kvm/mmu.h              |   2 +-
> >   arch/x86/kvm/svm/svm.c          |   4 +-
> >   arch/x86/kvm/vmx/vmx.c          | 134 ++++++++++++++++++--------------
> >   arch/x86/kvm/vmx/vmx.h          |  19 ++---
> >   5 files changed, 87 insertions(+), 76 deletions(-)
> > 
> 
> Queued, thanks.

Looks like this got shadow-banned, I'll send v4.