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From:   Vitaly Kuznetsov <vkuznets@redhat.com>
To:     Thadeu Lima de Souza Cascardo <cascardo@canonical.com>,
        Wanpeng Li <kernellwp@gmail.com>
Cc:     LKML <linux-kernel@vger.kernel.org>, kvm <kvm@vger.kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH] KVM: Pre-allocate 1 cpumask variable per cpu for both pv tlb and pv ipis
In-Reply-To: <20200204142733.GI40679@calabresa>
References: <CANRm+CwwYoSLeA3Squp-_fVZpmYmxEfqOB+DGoQN4Y_iMT347w@mail.gmail.com> <878slio6hp.fsf@vitty.brq.redhat.com> <CANRm+CzkN9oYf4UqWYp2SHFii02=pvVLbW4oNkLmPan7ZroDZA@mail.gmail.com> <20200204142733.GI40679@calabresa>
Date:   Tue, 04 Feb 2020 15:42:04 +0100
Message-ID: <871rrao1mr.fsf@vitty.brq.redhat.com>
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Thadeu Lima de Souza Cascardo <cascardo@canonical.com> writes:

>> > >      /*
>> > > @@ -624,6 +625,7 @@ static void __init kvm_guest_init(void)
>> > >          kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
>> > >          pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others;
>> > >          pv_ops.mmu.tlb_remove_table = tlb_remove_table;
>> > > +        pr_info("KVM setup pv remote TLB flush\n");
>> > >      }
>> > >
>
> I am more concerned about printing the "KVM setup pv remote TLB flush" message,
> not only when KVM pv is used, but pv TLB flush is not going to be used, but
> also when the system is not even paravirtualized.

Huh? In Wanpeng's patch this print is under

	if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
	    !kvm_para_has_hint(KVM_HINTS_REALTIME) &&
	    kvm_para_has_feature(KVM_FEATURE_STEAL_TIME))

and if you mean another patch we descussed before which was adding
 (!kvm_para_available() || nopv) check than it's still needed. Or,
alternatively, we can make kvm_para_has_feature() check for that.

-- 
Vitaly