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From:   KY Srinivasan <kys@microsoft.com>
To:     Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <kernellwp@gmail.com>
CC:     Radim Krcmar <rkrcmar@redhat.com>, kvm <kvm@vger.kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Roman Kagan <rkagan@virtuozzo.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>,
        LKML <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH 3/3] KVM: x86: hyperv: implement PV IPI send hypercalls
Thread-Topic: [PATCH 3/3] KVM: x86: hyperv: implement PV IPI send hypercalls
Thread-Index: AQHUCjky7sVBlzEva0m3QQTkSO6XC6RspcaAgAkX2ICAABCe/YAAAEHA
Date:   Thu, 28 Jun 2018 15:06:01 +0000
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> -----Original Message-----
> From: Vitaly Kuznetsov <vkuznets@redhat.com>
> Sent: Thursday, June 28, 2018 8:05 AM
> To: Wanpeng Li <kernellwp@gmail.com>
> Cc: Radim Krcmar <rkrcmar@redhat.com>; kvm <kvm@vger.kernel.org>;
> Paolo Bonzini <pbonzini@redhat.com>; Roman Kagan
> <rkagan@virtuozzo.com>; KY 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>; LKML <linux-
> kernel@vger.kernel.org>
> Subject: Re: [PATCH 3/3] KVM: x86: hyperv: implement PV IPI send
> hypercalls
>=20
> Wanpeng Li <kernellwp@gmail.com> writes:
>=20
> > Hi Paolo and Radim,
> >
> > I have already completed the patches for linux guest/kvm/qemu w/ vCPUs
> > <=3D 64, however, extra complication as the ex in hyperv should be
> > introduced for vCPUs > 64, so do you think vCPU <=3D64 is enough for
> > linux guest or should me introduce two hypercall as what hyperv does
> > w/ ex logic?
> >
>=20
> Neither Paolo nor Radim but as we already have
> #define KVM_MAX_VCPUS 288
> on at least x86, supporting <=3D 64 vCPUs seems to be too limiting for an=
y
> new functionality.

Agreed.

K. Y
>=20
> --
>   Vitaly