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From: Paolo Bonzini <pbonzini@redhat.com>
To: Ben Gardon <bgardon@google.com>,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Peter Xu <peterx@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Peter Shier <pshier@google.com>,
	Peter Feiner <pfeiner@google.com>,
	Junaid Shahid <junaids@google.com>,
	Jim Mattson <jmattson@google.com>,
	Yulei Zhang <yulei.kernel@gmail.com>,
	Wanpeng Li <kernellwp@gmail.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Xiao Guangrong <xiaoguangrong.eric@gmail.com>
Subject: Re: [PATCH 10/13] KVM: x86/mmu: Allow zapping collapsible SPTEs to use MMU read lock
Date: Thu, 1 Apr 2021 12:12:52 +0200	[thread overview]
Message-ID: <51034a41-2d03-103e-6c11-1ed27a952de2@redhat.com> (raw)
In-Reply-To: <20210331210841.3996155-11-bgardon@google.com>

On 31/03/21 23:08, Ben Gardon wrote:
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index dcbfc784cf2f..81967b4e7d76 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -5610,10 +5610,13 @@ void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm,
>   
>   	write_lock(&kvm->mmu_lock);
>   	slot_handle_leaf(kvm, slot, kvm_mmu_zap_collapsible_spte, true);
> -
> -	if (is_tdp_mmu_enabled(kvm))
> -		kvm_tdp_mmu_zap_collapsible_sptes(kvm, slot);
>   	write_unlock(&kvm->mmu_lock);
> +
> +	if (is_tdp_mmu_enabled(kvm)) {
> +		read_lock(&kvm->mmu_lock);
> +		kvm_tdp_mmu_zap_collapsible_sptes(kvm, memslot);
> +		read_unlock(&kvm->mmu_lock);
> +	}
>   }

Same here, this will conflict with

KVM: x86/mmu: Coalesce TLB flushes when zapping collapsible SPTEs

Again, you will have to add back some "if (flush)" before the write_unlock.

Paolo


  reply	other threads:[~2021-04-01 10:14 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-31 21:08 [PATCH 00/13] More parallel operations for the TDP MMU Ben Gardon
2021-03-31 21:08 ` [PATCH 01/13] KVM: x86/mmu: Re-add const qualifier in kvm_tdp_mmu_zap_collapsible_sptes Ben Gardon
2021-03-31 21:08 ` [PATCH 02/13] KVM: x86/mmu: Move kvm_mmu_(get|put)_root to TDP MMU Ben Gardon
2021-03-31 21:08 ` [PATCH 03/13] KVM: x86/mmu: use tdp_mmu_free_sp to free roots Ben Gardon
2021-03-31 21:08 ` [PATCH 04/13] KVM: x86/mmu: Merge TDP MMU put and free root Ben Gardon
2021-03-31 21:08 ` [PATCH 05/13] KVM: x86/mmu: comment for_each_tdp_mmu_root requires MMU write lock Ben Gardon
2021-03-31 21:08 ` [PATCH 06/13] KVM: x86/mmu: Refactor yield safe root iterator Ben Gardon
2021-03-31 21:08 ` [PATCH 07/13] KVM: x86/mmu: Make TDP MMU root refcount atomic Ben Gardon
2021-03-31 22:21   ` Sean Christopherson
2021-04-01 16:50     ` Ben Gardon
2021-03-31 21:08 ` [PATCH 08/13] KVM: x86/mmu: Protect the tdp_mmu_roots list with RCU Ben Gardon
2021-04-01  9:37   ` Paolo Bonzini
2021-04-01 16:48     ` Ben Gardon
2021-04-01 13:16   ` kernel test robot
2021-04-01 16:50     ` Ben Gardon
2021-03-31 21:08 ` [PATCH 09/13] KVM: x86/mmu: Allow zap gfn range to operate under the mmu read lock Ben Gardon
2021-04-01  9:58   ` Paolo Bonzini
2021-04-01 16:50     ` Ben Gardon
2021-03-31 21:08 ` [PATCH 10/13] KVM: x86/mmu: Allow zapping collapsible SPTEs to use MMU " Ben Gardon
2021-04-01 10:12   ` Paolo Bonzini [this message]
2021-03-31 21:08 ` [PATCH 11/13] KVM: x86/mmu: Allow enabling / disabling dirty logging under " Ben Gardon
2021-03-31 21:08 ` [PATCH 12/13] KVM: x86/mmu: Fast invalidation for TDP MMU Ben Gardon
2021-03-31 22:27   ` Sean Christopherson
2021-04-01 16:50     ` Ben Gardon
2021-04-01 10:36   ` Paolo Bonzini
2021-04-01 16:50     ` Ben Gardon
2021-04-01 17:02       ` Paolo Bonzini
2021-03-31 21:08 ` [PATCH 13/13] KVM: x86/mmu: Tear down roots in fast invalidation thread Ben Gardon
2021-03-31 22:29   ` Sean Christopherson
2021-04-01 10:41     ` Paolo Bonzini
2021-04-01 10:37   ` Paolo Bonzini
2021-04-01 10:43 ` [PATCH 00/13] More parallel operations for the TDP MMU Paolo Bonzini

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