linux-kernel - Re: [PATCH 2/2] KVM: x86/mmu: Pass parameter flush as false in kvm_tdp_mmu_zap_collapsible

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Message-ID: <e642702a-4455-9c1e-ac29-ba5809a2139c@redhat.com>
Date:   Wed, 17 Nov 2021 19:32:24 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Ben Gardon <bgardon@...gle.com>,
        Hou Wenlong <houwenlong93@...ux.alibaba.com>
Cc:     kvm@...r.kernel.org, Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] KVM: x86/mmu: Pass parameter flush as false in
 kvm_tdp_mmu_zap_collapsible_sptes()

On 11/17/21 18:50, Ben Gardon 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@...ux.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.
> 

And actually I had applied that before reading Sean's answer, so his 
follow up is not needed anymore.

Paolo