linux-kernel - Re: [PATCH 13/13] KVM: x86/mmu: Tear down roots in fast invalidation thread

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Message-ID: <YGT31GoDhVSXlgP4@google.com>
Date:   Wed, 31 Mar 2021 22:29:40 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Ben Gardon <bgardon@...gle.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        Peter Xu <peterx@...hat.com>, Peter Shier <pshier@...gle.com>,
        Peter Feiner <pfeiner@...gle.com>,
        Junaid Shahid <junaids@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        Yulei Zhang <yulei.kernel@...il.com>,
        Wanpeng Li <kernellwp@...il.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Xiao Guangrong <xiaoguangrong.eric@...il.com>
Subject: Re: [PATCH 13/13] KVM: x86/mmu: Tear down roots in fast invalidation
 thread

On Wed, Mar 31, 2021, Ben Gardon wrote:
> ---
>  arch/x86/kvm/mmu/mmu.c     |  6 ++++
>  arch/x86/kvm/mmu/tdp_mmu.c | 74 +++++++++++++++++++++++++++++++++++++-
>  arch/x86/kvm/mmu/tdp_mmu.h |  1 +
>  3 files changed, 80 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 49b7097fb55b..22742619698d 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -5455,6 +5455,12 @@ static void kvm_mmu_zap_all_fast(struct kvm *kvm)
>  	kvm_zap_obsolete_pages(kvm);
>  
>  	write_unlock(&kvm->mmu_lock);
> +
> +	if (is_tdp_mmu_enabled(kvm)) {
> +		read_lock(&kvm->mmu_lock);
> +		kvm_tdp_mmu_zap_all_fast(kvm);

Purely because it exists first, I think we should follow the legacy MMU's
terminology, i.e. kvm_tdp_mmu_zap_obsolete_pages().

> +		read_unlock(&kvm->mmu_lock);
> +	}
>  }