Re: [RFC PATCH 07/12] arm/sdei: override qemu_irq handler when binding interrupt

[Guoheyi <guoheyi@huawei.com>]

Hi Peter,

Thanks for your comments. I will explain SDEI in another mail and please 
provide your suggestions for such situation.

Heyi


On 2019/9/30 21:19, Peter Maydell wrote:
> On Tue, 24 Sep 2019 at 16:23, Heyi Guo <guoheyi@huawei.com> wrote:
>> Override qemu_irq handler to support trigger SDEI event transparently
>> after guest binds interrupt to SDEI event. We don't have good way to
>> get GIC device and to guarantee SDEI device is initialized after GIC,
>> so we search GIC in system bus when the first SDEI request happens or
>> in VMSTATE post_load().
>>
>> Signed-off-by: Heyi Guo <guoheyi@huawei.com>
>> Cc: Peter Maydell <peter.maydell@linaro.org>
>> Cc: Dave Martin <Dave.Martin@arm.com>
>> Cc: Marc Zyngier <marc.zyngier@arm.com>
>> Cc: Mark Rutland <mark.rutland@arm.com>
>> Cc: James Morse <james.morse@arm.com>
>
>> +static void override_qemu_irq(QemuSDEState *s, int32_t event, uint32_t intid)
>> +{
>> +    qemu_irq irq;
>> +    QemuSDE *sde;
>> +    CPUState *cs;
>> +    int cpu;
>> +
>> +    /* SPI */
>> +    if (intid >= GIC_INTERNAL) {
>> +        cs = arm_get_cpu_by_id(0);
>> +        irq = qdev_get_gpio_in(s->gic_dev,
>> +                               gic_int_to_irq(s->num_irq, intid, 0));
>> +        if (irq) {
>> +            qemu_irq_intercept_in(&irq, qemu_sdei_irq_handler, 1);
>> +        }
> I'm not sure what this code is trying to do, but
> qemu_irq_intercept_in() is a function for internal use
> by the qtest testing infrastructure, so it shouldn't be
> used in 'real' QEMU code.
>
>> +        sde = get_sde_no_check(s, event, cs);
>> +        sde->irq = irq;
>> +        put_sde(sde, cs);
>> +        return;
>> +    }
>> @@ -1042,6 +1152,17 @@ void sdei_handle_request(CPUState *cs, struct kvm_run *run)
>>           return;
>>       }
>>
>> +    if (!sde_state->gic_dev) {
>> +        /* Search for ARM GIC device */
>> +        qbus_walk_children(sysbus_get_default(), dev_walkerfn,
>> +                           NULL, NULL, NULL, sde_state);
>> +        if (!sde_state->gic_dev) {
>> +            error_report("Cannot find ARM GIC device!");
>> +            run->hypercall.args[0] = SDEI_NOT_SUPPORTED;
>> +            return;
>> +        }
>> +    }
> Walking through the qbus tree looking for particular devices
> isn't really something I'd recommend either.
>
> thanks
> -- PMM
>
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