Re: [Qemu-devel] [kvm-unit-tests PATCHv7 1/3] arm: Add PMU test

[cov@codeaurora.org]

On 2016-11-03 09:04, Andrew Jones wrote:
> On Thu, Nov 03, 2016 at 08:29:57AM -0600, cov@codeaurora.org wrote:
>> On 2016-11-03 04:14, Andrew Jones wrote:
>> > On Wed, Nov 02, 2016 at 05:22:15PM -0500, Wei Huang wrote:
>> >
>> > Missing
>> >  From: Christopher Covington <cov@codeaurora.org>
>> >
>> >
>> > > Beginning with a simple sanity check of the control register, add
>> > > a unit test for the ARM Performance Monitors Unit (PMU).
>> > >
>> > > Signed-off-by: Christopher Covington <cov@codeaurora.org>
>> >
>> > Missing
>> >   Signed-off-by: Wei Huang <wei@redhat.com>
>> >
>> > > ---
>> > >  arm/Makefile.common |  3 +-
>> > >  arm/pmu.c           | 82
>> > > +++++++++++++++++++++++++++++++++++++++++++++++++++++
>> > >  arm/unittests.cfg   | 20 +++++++++++++
>> > >  3 files changed, 104 insertions(+), 1 deletion(-)
>> > >  create mode 100644 arm/pmu.c
>> > >
>> > > diff --git a/arm/Makefile.common b/arm/Makefile.common
>> > > index ccb554d..f98f422 100644
>> > > --- a/arm/Makefile.common
>> > > +++ b/arm/Makefile.common
>> > > @@ -11,7 +11,8 @@ endif
>> > >
>> > >  tests-common = \
>> > >  	$(TEST_DIR)/selftest.flat \
>> > > -	$(TEST_DIR)/spinlock-test.flat
>> > > +	$(TEST_DIR)/spinlock-test.flat \
>> > > +	$(TEST_DIR)/pmu.flat
>> > >
>> > >  all: test_cases
>> > >
>> > > diff --git a/arm/pmu.c b/arm/pmu.c
>> > > new file mode 100644
>> > > index 0000000..42d0ee1
>> > > --- /dev/null
>> > > +++ b/arm/pmu.c
>> > > @@ -0,0 +1,82 @@
>> > > +/*
>> > > + * Test the ARM Performance Monitors Unit (PMU).
>> > > + *
>> > > + * Copyright 2015 The Linux Foundation. All rights reserved.
>> >
>> > Is the Linux Foundation correct for codeaurora patches? Should bump
>> > the year to 2016.
>> >
>> > > + *
>> > > + * This program is free software; you can redistribute it and/or
>> > > modify it
>> > > + * under the terms of the GNU Lesser General Public License version
>> > > 2.1 and
>> > > + * only version 2.1 as published by the Free Software Foundation.
>> > > + *
>> > > + * This program is distributed in the hope that it will be useful,
>> > > but WITHOUT
>> > > + * ANY WARRANTY; without even the implied warranty of
>> > > MERCHANTABILITY or
>> > > + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
>> > > Public License
>> > > + * for more details.
>> > > + */
>> > > +#include "libcflat.h"
>> > > +
>> > > +#if defined(__arm__)
>> > > +static inline uint32_t get_pmcr(void)
>> > > +{
>> > > +	uint32_t ret;
>> > > +
>> > > +	asm volatile("mrc p15, 0, %0, c9, c12, 0" : "=r" (ret));
>> > > +	return ret;
>> > > +}
>> > > +#elif defined(__aarch64__)
>> > > +static inline uint32_t get_pmcr(void)
>> > > +{
>> > > +	uint32_t ret;
>> > > +
>> > > +	asm volatile("mrs %0, pmcr_el0" : "=r" (ret));
>> > > +	return ret;
>> > > +}
>> > > +#endif
>> > > +
>> > > +struct pmu_data {
>> > > +	union {
>> > > +		uint32_t pmcr_el0;
>> > > +		struct {
>> > > +			uint32_t enable:1;
>> > > +			uint32_t event_counter_reset:1;
>> > > +			uint32_t cycle_counter_reset:1;
>> > > +			uint32_t cycle_counter_clock_divider:1;
>> > > +			uint32_t event_counter_export:1;
>> > > +			uint32_t cycle_counter_disable_when_prohibited:1;
>> > > +			uint32_t cycle_counter_long:1;
>> > > +			uint32_t reserved:4;
>> > > +			uint32_t counters:5;
>> > > +			uint32_t identification_code:8;
>> > > +			uint32_t implementer:8;
>> > > +		};
>> > > +	};
>> > > +};
>> >
>> > I know I already reviewed/agreed to this bitfield, but I'm having second
>> > thoughts. I think I'd prefer a bunch of defined shifts like the kernel
>> > uses.
>> >
>> > > +
>> > > +/*
>> > > + * As a simple sanity check on the PMCR_EL0, ensure the implementer
>> > > field isn't
>> > > + * null. Also print out a couple other interesting fields for
>> > > diagnostic
>> > > + * purposes. For example, as of fall 2015, QEMU TCG mode doesn't
>> > > implement
>> >
>> > s/2015/2016/   how time flies...
>> >
>> > > + * event counters and therefore reports zero event counters, but
>> > > hopefully
>> > > + * support for at least the instructions event will be added in the
>> > > future and
>> > > + * the reported number of event counters will become nonzero.
>> > > + */
>> > > +static bool check_pmcr(void)
>> > > +{
>> > > +	struct pmu_data pmu;
>> > > +
>> > > +	pmu.pmcr_el0 = get_pmcr();
>> > > +
>> > > +	printf("PMU implementer:     %c\n", pmu.implementer);
>> > > +	printf("Identification code: 0x%x\n", pmu.identification_code);
>> > > +	printf("Event counters:      %d\n", pmu.counters);
>> > > +
>> > > +	return pmu.implementer != 0;
>> > > +}
>> > > +
>> > > +int main(void)
>> > > +{
>> > > +	report_prefix_push("pmu");
>> > > +
>> > > +	report("Control register", check_pmcr());
>> > > +
>> > > +	return report_summary();
>> > > +}
>> > > diff --git a/arm/unittests.cfg b/arm/unittests.cfg
>> > > index 3f6fa45..b647b69 100644
>> > > --- a/arm/unittests.cfg
>> > > +++ b/arm/unittests.cfg
>> > > @@ -54,3 +54,23 @@ file = selftest.flat
>> > >  smp = $MAX_SMP
>> > >  extra_params = -append 'smp'
>> > >  groups = selftest
>> > > +
>> > > +# Test PMU support (KVM)
>> > > +[pmu-kvm]
>> > > +file = pmu.flat
>> > > +groups = pmu
>> > > +accel = kvm
>> >
>> > No need to specify kvm when it works for both. Both is assumed.
>> > tcg-only or kvm-only tests are exceptions requiring the 'accel'
>> > parameter and a comment explaining why it doesn't work on the
>> > other.
>> >
>> > > +
>> > > +# Test PMU support (TCG) with -icount IPC=1
>> > > +[pmu-tcg-icount-1]
>> > > +file = pmu.flat
>> > > +extra_params = -icount 0 -append '1'
>> > > +groups = pmu
>> > > +accel = tcg
>> > > +
>> > > +# Test PMU support (TCG) with -icount IPC=256
>> > > +[pmu-tcg-icount-256]
>> > > +file = pmu.flat
>> > > +extra_params = -icount 8 -append '256'
>> > > +groups = pmu
>> > > +accel = tcg
>> >
>> > Why are these entries added now. These tests aren't yet implemented.
>> 
>> What makes you say they aren't implemented? They're running the
>> same binary with a different command line arguments (that turns on
>> stricter TCG-specific checking).
> 
> Not in this patch, they're not. 'int main(void)' <-- arguments are
> ignored. Please only introduce unittests.cfg blocks with the patch
> that implements them.

Whoops, that's a rebase error. Sorry about that.

Cov