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From:   Wanpeng Li <kernellwp@gmail.com>
Date:   Thu, 21 Nov 2019 11:19:10 +0800
Message-ID: <CANRm+CxDOaBWuysZ-Q-3OvWegDkL0iyq-DXNjbeTZ6uSk5PG7A@mail.gmail.com>
Subject: Re: [PATCH v2 1/2] KVM: VMX: FIXED+PHYSICAL mode single target IPI fastpath
To:     Paolo Bonzini <pbonzini@redhat.com>
Cc:     Vitaly Kuznetsov <vkuznets@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>, kvm <kvm@vger.kernel.org>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>
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On Thu, 21 Nov 2019 at 01:43, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 19/11/19 13:26, Vitaly Kuznetsov wrote:
> > What about ' << 4', don't we still need it? :-) And better APIC_ICR
> > instead of 0x300...
> >
> > Personally, I'd write something like
> >
> > if (index > APIC_BASE_MSR && (index - APIC_BASE_MSR) == APIC_ICR >> 4)
> >
> > and let compiler optimize this, I bet it's going to be equally good.
>
> Or "index == APIC_BASE_MSR + (APIC_ICR >> 4)".

It is done in v3 and v4. Please have a look. :)

    Wanpeng