From: Ben Gardon <bgardon@google.com>
To: Hou Wenlong <houwenlong93@linux.alibaba.com>
Cc: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] KVM: x86/mmu: Pass parameter flush as false in kvm_tdp_mmu_zap_collapsible_sptes()
Date: Wed, 17 Nov 2021 09:50:46 -0800 [thread overview]
Message-ID: <CANgfPd_=M-8r8H5uoaPz_VTXZpmX6XD+QGAdBdz4PERUoqE1OA@mail.gmail.com> (raw)
In-Reply-To: <21453a1d2533afb6e59fb6c729af89e771ff2e76.1637140154.git.houwenlong93@linux.alibaba.com>
On Wed, Nov 17, 2021 at 1:20 AM Hou Wenlong
<houwenlong93@linux.alibaba.com> wrote:
>
> Since tlb flush has been done for legacy MMU before
> kvm_tdp_mmu_zap_collapsible_sptes(), so the parameter flush
> should be false for kvm_tdp_mmu_zap_collapsible_sptes().
>
> Fixes: e2209710ccc5d ("KVM: x86/mmu: Skip rmap operations if rmaps not allocated")
> Signed-off-by: Hou Wenlong <houwenlong93@linux.alibaba.com>
Haha, I'm glad we're thinking along similar lines. I just sent a patch
yesterday to remove the flush parameter from that function entirely:
https://lore.kernel.org/lkml/20211115234603.2908381-2-bgardon@google.com/
I'll CC you on that patch.
> ---
> arch/x86/kvm/mmu/mmu.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index d57319e596a9..4b2be04e9862 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -5853,7 +5853,7 @@ static bool kvm_mmu_zap_collapsible_spte(struct kvm *kvm,
> void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm,
> const struct kvm_memory_slot *slot)
> {
> - bool flush = false;
> + bool flush;
>
> if (kvm_memslots_have_rmaps(kvm)) {
> write_lock(&kvm->mmu_lock);
> @@ -5870,7 +5870,7 @@ void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm,
>
> if (is_tdp_mmu_enabled(kvm)) {
> read_lock(&kvm->mmu_lock);
> - flush = kvm_tdp_mmu_zap_collapsible_sptes(kvm, slot, flush);
> + flush = kvm_tdp_mmu_zap_collapsible_sptes(kvm, slot, false);
> if (flush)
> kvm_arch_flush_remote_tlbs_memslot(kvm, slot);
> read_unlock(&kvm->mmu_lock);
> --
> 2.31.1
>
next prev parent reply other threads:[~2021-11-17 17:51 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-17 9:20 [PATCH 1/2] KVM: x86/mmu: Skip tlb flush if it has been done in zap_gfn_range() Hou Wenlong
2021-11-17 9:20 ` [PATCH 2/2] KVM: x86/mmu: Pass parameter flush as false in kvm_tdp_mmu_zap_collapsible_sptes() Hou Wenlong
2021-11-17 17:50 ` Ben Gardon [this message]
2021-11-17 18:32 ` Paolo Bonzini
2021-11-17 15:56 ` [PATCH 1/2] KVM: x86/mmu: Skip tlb flush if it has been done in zap_gfn_range() Sean Christopherson
2021-11-17 16:45 ` Paolo Bonzini
2021-11-17 17:03 ` Sean Christopherson
2021-11-17 18:04 ` Sean Christopherson
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