From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:33013)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <abologna@redhat.com>) id 1bZEEm-0008Jz-As
	for qemu-devel@nongnu.org; Mon, 15 Aug 2016 05:31:17 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <abologna@redhat.com>) id 1bZEEl-00076w-Bp
	for qemu-devel@nongnu.org; Mon, 15 Aug 2016 05:31:16 -0400
Message-ID: <1471253464.3003.5.camel@redhat.com>
From: Andrea Bolognani <abologna@redhat.com>
Date: Mon, 15 Aug 2016 11:31:04 +0200
In-Reply-To: <1471067570-7503-1-git-send-email-wei@redhat.com>
References: <1471067570-7503-1-git-send-email-wei@redhat.com>
Content-Type: text/plain; charset="UTF-8"
Mime-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Subject: Re: [Qemu-devel] [PATCH V1 1/1] arm64: Add an option to turn on/off
 host-backed vPMU support
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel/>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Wei Huang <wei@redhat.com>, qemu-arm@nongnu.org
Cc: peter.maydell@linaro.org, drjones@redhat.com, shannon.zhao@linaro.org, qemu-devel@nongnu.org


On Sat, 2016-08-13 at 00:52 -0500, Wei Huang wrote:
> This patch adds a pmu=3D[on/off] option to enable/disable host vPMU
> support in guest VM. There are several reasons to justify this option.
> First, host-backed vPMU can be problematic for cross-migration between
> different SoC as perf counters are architecture-dependent. It is more
> flexible to have an option to turn it on/off. Secondly this option
> matches the "pmu" option as supported in libvirt tool.
>=C2=A0
> Note that, like "has_el3", the "pmu" option is only made available on
> CPUs that support host-backed vPMU. They include:
>=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0* cortex-a53 + kvm
>=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0* cortex-a57 + kvm
>=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0* host + kvm
> This option is removed in other configs where it doesn't make sense
> (e.g. cortex-a57 + TCG); and the default pmu support is off. This patch
> has been tested under both DT/ACPI modes.
>=C2=A0
> Signed-off-by: Wei Huang <wei@redhat.com>
> ---
>=C2=A0=C2=A0hw/arm/virt-acpi-build.c |=C2=A0=C2=A02 +-
>=C2=A0=C2=A0hw/arm/virt.c=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0|=C2=A0=C2=A02 +-
>=C2=A0=C2=A0target-arm/cpu.c=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0| 13 +++++++++++++
>=C2=A0=C2=A0target-arm/cpu.h=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0|=C2=A0=C2=A03 ++-
>=C2=A0=C2=A0target-arm/cpu64.c=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
|=C2=A0=C2=A06 ++++++
>=C2=A0=C2=A0target-arm/kvm64.c=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
| 10 +++++-----
>=C2=A0=C2=A06 files changed, 28 insertions(+), 8 deletions(-)

Did you already try driving this with libvirt? It should work
out of the box.

If you haven't, I will do it :)

--=C2=A0
Andrea Bolognani / Red Hat / Virtualization