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Date:   Fri, 29 Jun 2018 18:01:05 +0300
From:   Roman Kagan <rkagan@virtuozzo.com>
To:     Vitaly Kuznetsov <vkuznets@redhat.com>
Cc:     kvm@vger.kernel.org, x86@kernel.org,
        Paolo Bonzini <pbonzini@redhat.com>,
        Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>,
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        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>,
        Mohammed Gamal <mmorsy@redhat.com>,
        Cathy Avery <cavery@redhat.com>,
        Wanpeng Li <wanpeng.li@hotmail.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 3/5] KVM: x86: hyperv: use get_vcpu_by_vpidx() in
 kvm_hv_flush_tlb()
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On Fri, Jun 29, 2018 at 04:14:53PM +0200, Vitaly Kuznetsov wrote:
> VP_INDEX almost always matches VCPU id and get_vcpu_by_vpidx() is fast,
> use it instead of traversing full vCPU list every time.
> 
> To support the change switch kvm_make_vcpus_request_mask() to checking
> vcpu_id instead of vcpu index,

I'm afraid you can't do this: vcpu_id (== apic id) can be sparse, i.e.
it's not very well suited for bitmaps and can exceed the max number of
vcpus.

Roman.