Re: [kvm-unit-tests PATCH v1 1/4] arm64: split its-trigger test into KVM and TCG variants

["Alex Bennée" <alex.bennee@linaro.org>]

Marc Zyngier <maz@kernel.org> writes:

> On 2021-04-28 11:18, Alex Bennée wrote:
>> A few of the its-trigger tests rely on IMPDEF behaviour where caches
>> aren't flushed before invall events. However TCG emulation doesn't
>> model any invall behaviour and as we can't probe for it we need to be
>> told. Split the test into a KVM and TCG variant and skip the invall
>> tests when under TCG.
>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>> Cc: Shashi Mallela <shashi.mallela@linaro.org>
>> ---
>>  arm/gic.c         | 60 +++++++++++++++++++++++++++--------------------
>>  arm/unittests.cfg | 11 ++++++++-
>>  2 files changed, 45 insertions(+), 26 deletions(-)
>> diff --git a/arm/gic.c b/arm/gic.c
>> index 98135ef..96a329d 100644
>> --- a/arm/gic.c
>> +++ b/arm/gic.c
>> @@ -36,6 +36,7 @@ static struct gic *gic;
>>  static int acked[NR_CPUS], spurious[NR_CPUS];
>>  static int irq_sender[NR_CPUS], irq_number[NR_CPUS];
>>  static cpumask_t ready;
>> +static bool under_tcg;
>>  static void nr_cpu_check(int nr)
>>  {
>> @@ -734,32 +735,38 @@ static void test_its_trigger(void)
>>  	/*
>>  	 * re-enable the LPI but willingly do not call invall
>>  	 * so the change in config is not taken into account.
>> -	 * The LPI should not hit
>> +	 * The LPI should not hit. This does however depend on
>> +	 * implementation defined behaviour - under QEMU TCG emulation
>> +	 * it can quite correctly process the event directly.
>
> It looks to me that you are using an IMPDEF behaviour of *TCG*
> here. The programming model mandates that there is an invalidation
> if you change the configuration of the LPI.

But does it mandate that the LPI cannot be sent until the invalidation?

>
>         M.


-- 
Alex Bennée