From: "Nicholas Piggin" <npiggin@gmail.com>
To: "Michael Ellerman" <mpe@ellerman.id.au>,
"Gautam Menghani" <gautam@linux.ibm.com>,
<christophe.leroy@csgroup.eu>, <naveen.n.rao@linux.ibm.com>
Cc: <linuxppc-dev@lists.ozlabs.org>, <kvm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>,
"Vaibhav Jain" <vaibhav@linux.ibm.com>
Subject: Re: [PATCH v6] arch/powerpc/kvm: Add support for reading VPA counters for pseries guests
Date: Thu, 09 May 2024 15:42:46 +1000 [thread overview]
Message-ID: <D14VHEQLAB3V.30DDBZFDKZVGY@gmail.com> (raw)
In-Reply-To: <87o79gmqek.fsf@mail.lhotse>
On Wed May 8, 2024 at 10:36 PM AEST, Michael Ellerman wrote:
> Gautam Menghani <gautam@linux.ibm.com> writes:
> > PAPR hypervisor has introduced three new counters in the VPA area of
> > LPAR CPUs for KVM L2 guest (see [1] for terminology) observability - 2
> > for context switches from host to guest and vice versa, and 1 counter
> > for getting the total time spent inside the KVM guest. Add a tracepoint
> > that enables reading the counters for use by ftrace/perf. Note that this
> > tracepoint is only available for nestedv2 API (i.e, KVM on PowerVM).
> ...
> > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> > index 8e86eb577eb8..ed69ad58bd02 100644
> > --- a/arch/powerpc/kvm/book3s_hv.c
> > +++ b/arch/powerpc/kvm/book3s_hv.c
> > @@ -4108,6 +4108,54 @@ static void vcpu_vpa_increment_dispatch(struct kvm_vcpu *vcpu)
> > }
> > }
> >
> > +static inline int kvmhv_get_l2_counters_status(void)
> > +{
> > + return get_lppaca()->l2_counters_enable;
> > +}
>
> This is breaking the powernv build:
[...]
All the nested KVM code should really go under CONFIG_PSERIES.
Possibly even moved out to its own file.
For now maybe you could just ifdef these few functions and
replace with noop variants for !PSERIES.
Thanks,
Nick
prev parent reply other threads:[~2024-05-09 5:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-06 14:56 [PATCH v6] arch/powerpc/kvm: Add support for reading VPA counters for pseries guests Gautam Menghani
2024-05-07 6:35 ` Naveen N Rao
2024-05-08 12:21 ` Nicholas Piggin
2024-05-08 12:36 ` Michael Ellerman
2024-05-09 5:42 ` Nicholas Piggin [this message]
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