linux-kernel - Re: [PATCH] KVM: LAPIC: Recalculate apic map in batch

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Message-ID: <629c37b6-2589-9073-369c-7026ebf13a51@redhat.com>
Date:   Tue, 25 Feb 2020 09:50:26 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Wanpeng Li <kernellwp@...il.com>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>, kvm <kvm@...r.kernel.org>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>
Subject: Re: [PATCH] KVM: LAPIC: Recalculate apic map in batch

On 25/02/20 09:31, Wanpeng Li wrote:
> On Tue, 25 Feb 2020 at 16:07, Paolo Bonzini <pbonzini@...hat.com> wrote:
>>
>> On 19/02/20 01:47, Wanpeng Li wrote:
>>>> An alternative idea: instead of making every caller return bool and
>>>> every call site handle the result (once) just add a
>>>> KVM_REQ_APIC_MAP_RECALC flag or a boolean flag to struct kvm. I
>>>> understand it may not be that easy as it sounds as we may be conunting
>>>> on valid mapping somewhere before we actually get to handiling
>>> Yes.
>>>
>>>> KVM_REQ_APIC_MAP_RECALC but we may preserve *some*
>>>> recalculate_apic_map() calls (and make it reset KVM_REQ_APIC_MAP_RECALC).
>>> Paolo, keep the caller return bool or add a booleen flag to struct
>>> kvm, what do you think?
>>
>> A third possibility: add an apic_map field to struct kvm_lapic, so that
>> you don't have to add bool return values everywhere.
> 
> This apic_map field is boolean, right?

Right, and the name should really be apic_map_dirty.

Paolo