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

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Message-ID: <7ed340f1-f6f7-4682-65be-6bc02f25d612@redhat.com>
Date:   Wed, 27 Jan 2021 19:10:42 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Sean Christopherson <seanjc@...gle.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 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.

Paolo