Re: [Qemu-arm] [PATCH V1 1/1] arm64: Add an option to turn on/off host-backed vPMU support

[Andrea Bolognani <abologna@redhat.com>]

On Sat, 2016-08-13 at 00:52 -0500, Wei Huang wrote:
> This patch adds a pmu=[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.
> 
> Note that, like "has_el3", the "pmu" option is only made available on
> CPUs that support host-backed vPMU. They include:
>     * cortex-a53 + kvm
>     * cortex-a57 + kvm
>     * 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.
> 
> Signed-off-by: Wei Huang <wei@redhat.com>
> ---
>  hw/arm/virt-acpi-build.c |  2 +-
>  hw/arm/virt.c            |  2 +-
>  target-arm/cpu.c         | 13 +++++++++++++
>  target-arm/cpu.h         |  3 ++-
>  target-arm/cpu64.c       |  6 ++++++
>  target-arm/kvm64.c       | 10 +++++-----
>  6 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 :)

-- 
Andrea Bolognani / Red Hat / Virtualization