From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paul Mackerras <paulus@ozlabs.org>
Subject: Re: [PATCH v2 03/16] KVM: PPC: Book3S HV: XIVE: introduce a new
 capability KVM_CAP_PPC_IRQ_XIVE
Date: Mon, 25 Feb 2019 15:59:31 +1100
Message-ID: <20190225045931.GB20501@blackberry>
References: <20190222112840.25000-1-clg@kaod.org>
 <20190222112840.25000-4-clg@kaod.org>
 <20190225003527.GG7668@umbus.fritz.box>
Mime-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8bit
Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org,
 =?iso-8859-1?Q?C=E9dric?= Le Goater <clg@kaod.org>,
 linuxppc-dev@lists.ozlabs.org
To: David Gibson <david@gibson.dropbear.id.au>
Return-path: <linuxppc-dev-bounces+glppe-linuxppc-embedded-2=m.gmane.org@lists.ozlabs.org>
Content-Disposition: inline
In-Reply-To: <20190225003527.GG7668@umbus.fritz.box>
List-Unsubscribe: <https://lists.ozlabs.org/options/linuxppc-dev>,
 <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=unsubscribe>
List-Archive: <http://lists.ozlabs.org/pipermail/linuxppc-dev/>
List-Post: <mailto:linuxppc-dev@lists.ozlabs.org>
List-Help: <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=help>
List-Subscribe: <https://lists.ozlabs.org/listinfo/linuxppc-dev>,
 <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=subscribe>
Errors-To: linuxppc-dev-bounces+glppe-linuxppc-embedded-2=m.gmane.org@lists.ozlabs.org
Sender: "Linuxppc-dev"
 <linuxppc-dev-bounces+glppe-linuxppc-embedded-2=m.gmane.org@lists.ozlabs.org>
List-Id: kvm.vger.kernel.org

On Mon, Feb 25, 2019 at 11:35:27AM +1100, David Gibson wrote:
> On Fri, Feb 22, 2019 at 12:28:27PM +0100, Cédric Le Goater wrote:
> > +	xc->xive = xive;
> > +	xc->vcpu = vcpu;
> > +	xc->server_num = cpu;
> > +	xc->vp_id = xive->vp_base + cpu;
> 
> Hrm.  This ties the internal VP id to the userspace chosen server
> number, which isn't ideal.  It puts a constraint on those server
> numbers that you wouldn't otherwise have.

We should probably do the same as the xics-on-xive code, which is to
put the server number through kvmppc_pack_vcpu_id(), which is a
folding function that maps the QEMU vcpu id (which is the server
number) down to the range 0..KVM_MAX_VCPUS-1, and works for the
allocation patterns used in the various vSMT modes.

Paul.

From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paul Mackerras <paulus@ozlabs.org>
Date: Mon, 25 Feb 2019 04:59:31 +0000
Subject: Re: [PATCH v2 03/16] KVM: PPC: Book3S HV: XIVE: introduce a new capability KVM_CAP_PPC_IRQ_XIVE
Message-Id: <20190225045931.GB20501@blackberry>
List-Id: <kvm-ppc.vger.kernel.org>
References: <20190222112840.25000-1-clg@kaod.org>
 <20190222112840.25000-4-clg@kaod.org>
 <20190225003527.GG7668@umbus.fritz.box>
In-Reply-To: <20190225003527.GG7668@umbus.fritz.box>
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
To: David Gibson <david@gibson.dropbear.id.au>
Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, =?iso-8859-1?Q?C=E9dric?= Le Goater <clg@kaod.org>, linuxppc-dev@lists.ozlabs.org

On Mon, Feb 25, 2019 at 11:35:27AM +1100, David Gibson wrote:
> On Fri, Feb 22, 2019 at 12:28:27PM +0100, C=E9dric Le Goater wrote:
> > +	xc->xive =3D xive;
> > +	xc->vcpu =3D vcpu;
> > +	xc->server_num =3D cpu;
> > +	xc->vp_id =3D xive->vp_base + cpu;
>=20
> Hrm.  This ties the internal VP id to the userspace chosen server
> number, which isn't ideal.  It puts a constraint on those server
> numbers that you wouldn't otherwise have.

We should probably do the same as the xics-on-xive code, which is to
put the server number through kvmppc_pack_vcpu_id(), which is a
folding function that maps the QEMU vcpu id (which is the server
number) down to the range 0..KVM_MAX_VCPUS-1, and works for the
allocation patterns used in the various vSMT modes.

Paul.