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From:   Vitaly Kuznetsov <vkuznets@redhat.com>
To:     kvm@vger.kernel.org
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        Roman Kagan <rkagan@virtuozzo.com>,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        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 v4 0/5] KVM: x86: hyperv: PV IPI support for Windows guests
References: <20180703134206.27240-1-vkuznets@redhat.com>
Date:   Mon, 23 Jul 2018 13:31:12 +0200
In-Reply-To: <20180703134206.27240-1-vkuznets@redhat.com> (Vitaly Kuznetsov's
        message of "Tue, 3 Jul 2018 15:42:01 +0200")
Message-ID: <87tvoqrxxb.fsf@vitty.brq.redhat.com>
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Vitaly Kuznetsov <vkuznets@redhat.com> writes:

> Changes since v3 [Roman Kagan]:
> - Don't use vcpu_id in kvm_make_vcpus_request_mask to avoid dealing with
>   sparse CPU masks.
> - Create get_vcpu_idx_by_vpidx() and use it in get_vcpu_by_vpidx() and
>   kvm_hv_flush_tlb().
>
> Using hypercall for sending IPIs is faster because this allows to specify
> any number of vCPUs (even > 64 with sparse CPU set), the whole procedure
> will take only one VMEXIT.
>
> Same as PV TLB flush, this allows Windows guests having > 64 vCPUs to boot
> on KVM when Hyper-V extensions are enabled.

Ping)

-- 
  Vitaly