Re: [kvm-unit-tests PATCH v2 3/8] arm64: microbench: gic: Add gicv4.1 support for ipi latency test.

[Jingyi Wang <wangjingyi11@huawei.com>]

On 7/2/2020 9:42 PM, Auger Eric wrote:
> Hi Marc,
> 
> On 7/2/20 3:08 PM, Marc Zyngier wrote:
>> Hi Eric,
>>
>> On 2020-07-02 13:57, Auger Eric wrote:
>>> Hi Jingyi,
>>>
>>> On 7/2/20 5:01 AM, Jingyi Wang wrote:
>>>> If gicv4.1(sgi hardware injection) supported, we test ipi injection
>>>> via hw/sw way separately.
>>>>
>>>> Signed-off-by: Jingyi Wang <wangjingyi11@huawei.com>
>>>> ---
>>>>   arm/micro-bench.c    | 45 +++++++++++++++++++++++++++++++++++++++-----
>>>>   lib/arm/asm/gic-v3.h |  3 +++
>>>>   lib/arm/asm/gic.h    |  1 +
>>>>   3 files changed, 44 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/arm/micro-bench.c b/arm/micro-bench.c
>>>> index fc4d356..80d8db3 100644
>>>> --- a/arm/micro-bench.c
>>>> +++ b/arm/micro-bench.c
>>>> @@ -91,9 +91,40 @@ static void gic_prep_common(void)
>>>>       assert(irq_ready);
>>>>   }
>>>>
>>>> -static void ipi_prep(void)
>>>> +static bool ipi_prep(void)
>>> Any reason why the bool returned value is preferred over the standard
>>> int?
>>>>   {
>>>> +    u32 val;
>>>> +
>>>> +    val = readl(vgic_dist_base + GICD_CTLR);
>>>> +    if (readl(vgic_dist_base + GICD_TYPER2) & GICD_TYPER2_nASSGIcap) {
>>>> +        val &= ~GICD_CTLR_ENABLE_G1A;
>>>> +        val &= ~GICD_CTLR_nASSGIreq;
>>>> +        writel(val, vgic_dist_base + GICD_CTLR);
>>>> +        val |= GICD_CTLR_ENABLE_G1A;
>>>> +        writel(val, vgic_dist_base + GICD_CTLR);
>>> Why do we need this G1A dance?
>>
>> Because it isn't legal to change the SGI behaviour when groups are enabled.
>> Yes, it is described in this bit of documentation nobody has access to.
> 
> OK thank you for the explanation. Jingyi, maybe add a comment to avoid
> the question again ;-)
> 
> Thanks
> 
> Eric

Okay, I will add a comment here in the next version.

Thanks,
Jingyi

>>
>> And this code needs to track RWP on disabling Group-1.
>>
>>          M.
> 
> 
> .
>