Re: [Qemu-devel] [kvm-unit-tests PATCH 1/4] arm/arm64: GIC: basic GICv2 MMIO tests

[Andre Przywara]

Hi Drew,

On 18/11/16 13:06, Andrew Jones wrote:
> Hi Andre,
> 
> I'm so pleased to see this series. Thank you!
> 
> On Thu, Nov 17, 2016 at 05:57:49PM +0000, Andre Przywara wrote:
>> This adds an MMIO subtest to the GIC test.
>> It accesses some generic GICv2 registers and does some sanity tests,
>> like checking for some of them being read-only.
>>
>> Signed-off-by: Andre Przywara <address@hidden>
>> ---
>>  arm/gic.c         | 99 
>> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  arm/unittests.cfg |  6 ++++
>>  lib/arm/asm/gic.h |  2 ++
>>  3 files changed, 107 insertions(+)
>>
>> diff --git a/arm/gic.c b/arm/gic.c
>> index 638b8b1..ba2585b 100644
>> --- a/arm/gic.c
>> +++ b/arm/gic.c
>> @@ -3,6 +3,7 @@
>>   *
>>   * GICv2
>>   *   + test sending/receiving IPIs
>> + *   + MMIO access tests
>>   * GICv3
>>   *   + test sending/receiving IPIs
>>   *
>> @@ -274,6 +275,98 @@ static struct gic gicv3 = {
>>      },
>>  };
>>  
>> +static bool test_ro_pattern_32(void *address, u32 pattern, u32 orig)
>> +{
>> +    u32 reg;
>> +
>> +    writel(pattern, address);
>> +    reg = readl(address);
>> +
>> +    if (reg != orig)
>> +            writel(orig, address);
>> +
>> +    return reg == orig;
>> +}
>> +
>> +static bool test_readonly_32(void *address, bool razwi)
>> +{
>> +    u32 orig, pattern;
>> +
>> +    orig = readl(address);
>> +    if (razwi && orig)
>> +            return false;
>> +
>> +    pattern = 0xffffffff;
>> +    if (orig != pattern) {
>> +            if (!test_ro_pattern_32(address, pattern, orig))
>> +                    return false;
>> +    }
>> +
>> +    pattern = 0xa5a55a5a;
>> +    if (orig != pattern) {
>> +            if (!test_ro_pattern_32(address, pattern, orig))
>> +                    return false;
>> +    }
>> +
>> +    pattern = 0;
>> +    if (orig != pattern) {
>> +            if (!test_ro_pattern_32(address, pattern, orig))
>> +                    return false;
>> +    }
>> +
>> +    return true;
>> +}
>> +
>> +static bool test_typer_v2(uint32_t reg)
>> +{
>> +    int nr_gic_cpus = ((reg >> 5) & 0x7) + 1;
>> +
>> +    report("all %d CPUs have interrupts", nr_cpus == nr_gic_cpus,
>> +           nr_gic_cpus);
>> +
>> +    return true;
> 
> This test function can be a void.
> 
>> +}
>> +
>> +static int gic_test_mmio(int gic_version)
>> +{
>> +    u32 reg;
>> +    int nr_irqs;
>> +    void *gic_dist_base, *idreg;
>> +
>> +    switch(gic_version) {
>> +    case 0x2:
>> +            gic_dist_base = gicv2_dist_base();
>> +            idreg = gic_dist_base + 0xfe8;
> 
> I see below you introduce GICD_ICPIDR2, so I guess you can use it here.
> 
>> +            break;
>> +    case 0x3:
>> +            report_abort("GICv3 MMIO tests NYI");
>> +            return -1;
> 
> can't reach this return

But we need to tell GCC about this, because otherwise we get all kind of
warnings (including bogus "maybe unused" warnings).
__attribute__ ((noreturn)) seems the way to go here, but this is
currently giving me a hard time ...

>> +    default:
>> +            report_abort("GIC version %d not supported", gic_version);
>> +            return 0;
> 
> can't reach this return
> 
>> +    }
>> +
>> +    reg = readl(gic_dist_base + GICD_TYPER);
>> +    nr_irqs = 32 * ((reg & 0x1f) + 1);
> 
> Any reason to avoid using GICD_TYPER_IRQS() here?

On the first write I wasn't aware of it, on a second thought then I
wanted to avoid using the macro copied from Linux.

But you are right, I will use it here.

> 
>> +    report("number of implemented SPIs: %d", 1, nr_irqs - 32);
> 
> We usually just use printf for informational output (but we should
> probably add a 'report_info' in order to keep the prefixes. I can
> do that now.) Anyway, please s/1/true

I saw your patch, will use that.

>> +
>> +    test_typer_v2(reg);
>> +
>> +    report("IIDR: 0x%x", 1, readl(gic_dist_base + GICD_IIDR));
>> +
>> +    report("GICD_TYPER is read-only",
>> +           test_readonly_32(gic_dist_base + GICD_TYPER, false));
>> +    report("GICD_IIDR is read-only",
>> +           test_readonly_32(gic_dist_base + GICD_IIDR, false));
>> +
>> +    reg = readl(idreg);
>> +    report("ICPIDR2 is read-only (0x%x)",
>> +           test_readonly_32(idreg, false),
>> +           reg);
>> +
>> +    return 0;
> 
> You may want %08x for all your register printing.
> 
> Since you either abort or always return success, then this function can be
> a void.
> 
>> +}
>> +
>>  int main(int argc, char **argv)
>>  {
>>      char pfx[8];
>> @@ -332,6 +425,12 @@ int main(int argc, char **argv)
>>              }
>>              ipi_test();
>>  
>> +    } else if (!strcmp(argv[1], "mmio")) {
>> +            report_prefix_push(argv[1]);
>> +
>> +            gic_test_mmio(gic_version());
> 
> Any reason to pass gic_version() here instead of just using it
> in gic_test_mmio?

Not really, I originally wanted to pass this variable on in a clean
fashion to allow sharing tests.
But using the function shouldn't make any difference anymore, so I can
easily replace it.

"Yes, will fix" to all the other comments.

Thanks for having a look!

Cheers,
Andre.

>> +
>> +            report_prefix_pop();
>>      } else {
>>              report_abort("Unknown subtest '%s'", argv[1]);
>>      }
>> diff --git a/arm/unittests.cfg b/arm/unittests.cfg
>> index c7392c7..0162e5a 100644
>> --- a/arm/unittests.cfg
>> +++ b/arm/unittests.cfg
>> @@ -67,6 +67,12 @@ smp = $((($MAX_SMP < 8)?$MAX_SMP:8))
>>  extra_params = -machine gic-version=2 -append 'ipi'
>>  groups = gic
>>  
>> +[gicv2-mmio]
>> +file = gic.flat
>> +smp = $((($MAX_SMP < 8)?$MAX_SMP:8))
>> +extra_params = -machine gic-version=2 -append 'mmio'
>> +groups = gic
>> +
>>  [gicv3-ipi]
>>  file = gic.flat
>>  smp = $MAX_SMP
>> diff --git a/lib/arm/asm/gic.h b/lib/arm/asm/gic.h
>> index c2267b6..cef748d 100644
>> --- a/lib/arm/asm/gic.h
>> +++ b/lib/arm/asm/gic.h
>> @@ -10,10 +10,12 @@
>>  /* Distributor registers */
>>  #define GICD_CTLR                   0x0000
>>  #define GICD_TYPER                  0x0004
>> +#define GICD_IIDR                   0x0008
>>  #define GICD_IGROUPR                        0x0080
>>  #define GICD_ISENABLER                      0x0100
>>  #define GICD_IPRIORITYR                     0x0400
>>  #define GICD_SGIR                   0x0f00
>> +#define GICD_ICPIDR2                        0x0fe8
>>  
>>  #define GICD_TYPER_IRQS(typer)              ((((typer) & 0x1f) + 1) * 32)
>>  #define GICD_INT_EN_SET_SGI         0x0000ffff
>> -- 
>> 2.9.0
>>
>>
> 
> Thanks,
> drew 
>