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From: Marc Zyngier <maz@kernel.org>
To: Zenghui Yu <yuzenghui@huawei.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Jason Cooper <jason@lakedaemon.net>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Robert Richter <rrichter@marvell.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v4 08/20] irqchip/gic-v4.1: Plumb get/set_irqchip_state SGI callbacks
Date: Fri, 28 Feb 2020 19:37:48 +0000
Message-ID: <dd9f1224b3b21ad793862406bd8855ba@kernel.org> (raw)
In-Reply-To: <3d725ede-6631-59fb-1a10-9fb9890f3df6@huawei.com>

On 2020-02-20 03:11, Zenghui Yu wrote:
> Hi Marc,
> 
> On 2020/2/18 23:31, Marc Zyngier wrote:
>> diff --git a/drivers/irqchip/irq-gic-v3-its.c 
>> b/drivers/irqchip/irq-gic-v3-its.c
>> index 7656b353a95f..0ed286dba827 100644
>> --- a/drivers/irqchip/irq-gic-v3-its.c
>> +++ b/drivers/irqchip/irq-gic-v3-its.c
>> @@ -144,7 +144,7 @@ struct event_lpi_map {
>>       u16            *col_map;
>>       irq_hw_number_t        lpi_base;
>>       int            nr_lpis;
>> -    raw_spinlock_t        vlpi_lock;
>> +    raw_spinlock_t        map_lock;
> 
> So we use map_lock to protect both LPI's and VLPI's mapping affinity of
> a device, and use vpe_lock to protect vPE's affinity, OK.
> 
>>       struct its_vm        *vm;
>>       struct its_vlpi_map    *vlpi_maps;
>>       int            nr_vlpis;
>> @@ -240,15 +240,33 @@ static struct its_vlpi_map *get_vlpi_map(struct 
>> irq_data *d)
>>       return NULL;
>>   }
>> 
>> -static int irq_to_cpuid(struct irq_data *d)
>> +static int irq_to_cpuid_lock(struct irq_data *d, unsigned long 
>> *flags)
>>   {
>> -    struct its_device *its_dev = irq_data_get_irq_chip_data(d);
>>       struct its_vlpi_map *map = get_vlpi_map(d);
>> +    int cpu;
>> 
>> -    if (map)
>> -        return map->vpe->col_idx;
>> +    if (map) {
>> +        raw_spin_lock_irqsave(&map->vpe->vpe_lock, *flags);
>> +        cpu = map->vpe->col_idx;
>> +    } else {
>> +        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
>> +        raw_spin_lock_irqsave(&its_dev->event_map.map_lock, *flags);
>> +        cpu = its_dev->event_map.col_map[its_get_event_id(d)];
>> +    }
>> 
>> -    return its_dev->event_map.col_map[its_get_event_id(d)];
>> +    return cpu;
>> +}
> 
> This helper is correct for normal LPIs and VLPIs, but wrong for per-vPE
> IRQ (doorbell) and vSGIs. irq_data_get_irq_chip_data() gets confused by
> both of them.

Yes, I've fixed that in the current state of the tree last week. Do have 
a
look if you can, but it seems to survive on both the model with v4.1 and
my D05.

[...]

>> -        rdbase = per_cpu_ptr(gic_rdists->rdist, 
>> vpe->col_idx)->rd_base;
>> +        cpu = irq_to_cpuid_lock(d, &flags);
>> +        rdbase = per_cpu_ptr(gic_rdists->rdist, cpu)->rd_base;
>>           gic_write_lpir(d->parent_data->hwirq, rdbase + 
>> GICR_INVLPIR);
>>           wait_for_syncr(rdbase);
>> +        irq_to_cpuid_unlock(d, flags);
>>       } else {
>>           its_vpe_send_cmd(vpe, its_send_inv);
>>       }
> 
> Do we really need to grab the vpe_lock for those which are belong to
> the same irqchip with its_vpe_set_affinity()? The IRQ core code should
> already ensure the mutual exclusion among them, wrong?

I've been trying to think about that, but jet-lag keeps getting in the 
way.
I empirically think that you are right, but I need to go and check the 
various
code paths to be sure. Hopefully I'll have a bit more brain space next 
week.

For sure this patch tries to do too many things at once...

         M.
-- 
Jazz is not dead. It just smells funny...
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  reply index

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-14 14:57 [PATCH v4 00/20] irqchip/gic-v4: GICv4.1 architecture support Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 01/20] irqchip/gic-v4.1: Skip absent CPUs while iterating over redistributors Marc Zyngier
2020-02-17  9:11   ` Zenghui Yu
2020-02-14 14:57 ` [PATCH v4 02/20] irqchip/gic-v3: Use SGIs without active state if offered Marc Zyngier
2020-02-17  9:18   ` Zenghui Yu
2020-02-14 14:57 ` [PATCH v4 03/20] irqchip/gic-v4.1: Advertise support v4.1 to KVM Marc Zyngier
2020-02-17  9:09   ` Zenghui Yu
2020-02-14 14:57 ` [PATCH v4 04/20] irqchip/gic-v4.1: Map the ITS SGIR register page Marc Zyngier
2020-02-20  3:17   ` Zenghui Yu
2020-02-14 14:57 ` [PATCH v4 05/20] irqchip/gic-v4.1: Plumb skeletal VSGI irqchip Marc Zyngier
2020-02-20  3:21   ` Zenghui Yu
2020-02-14 14:57 ` [PATCH v4 06/20] irqchip/gic-v4.1: Add initial SGI configuration Marc Zyngier
2020-02-18  7:25   ` Zenghui Yu
2020-02-18  9:46     ` Marc Zyngier
2020-02-20  3:25       ` Zenghui Yu
2020-02-14 14:57 ` [PATCH v4 07/20] irqchip/gic-v4.1: Plumb mask/unmask SGI callbacks Marc Zyngier
2020-02-20  3:32   ` Zenghui Yu
2020-02-14 14:57 ` [PATCH v4 08/20] irqchip/gic-v4.1: Plumb get/set_irqchip_state " Marc Zyngier
2020-02-18  7:00   ` Zenghui Yu
2020-02-18  9:27     ` Marc Zyngier
2020-02-18 15:31       ` Marc Zyngier
2020-02-19 11:50         ` Zenghui Yu
2020-02-19 15:18           ` Zenghui Yu
2020-02-20  3:11         ` Zenghui Yu
2020-02-28 19:37           ` Marc Zyngier [this message]
2020-03-01 19:00             ` Marc Zyngier
2020-03-02  8:18               ` Zenghui Yu
2020-03-02 12:09                 ` Marc Zyngier
2020-03-02 14:21                   ` Bill Barrow
2020-02-14 14:57 ` [PATCH v4 09/20] irqchip/gic-v4.1: Plumb set_vcpu_affinity " Marc Zyngier
2020-02-20  3:37   ` Zenghui Yu
2020-02-28 19:00     ` Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 10/20] irqchip/gic-v4.1: Move doorbell management to the GICv4 abstraction layer Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 11/20] irqchip/gic-v4.1: Add VSGI allocation/teardown Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 12/20] irqchip/gic-v4.1: Add VSGI property setup Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 13/20] irqchip/gic-v4.1: Eagerly vmap vPEs Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 14/20] KVM: arm64: GICv4.1: Let doorbells be auto-enabled Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 15/20] KVM: arm64: GICv4.1: Add direct injection capability to SGI registers Marc Zyngier
2020-02-18  8:46   ` Zenghui Yu
2020-02-18  9:41     ` Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 16/20] KVM: arm64: GICv4.1: Allow SGIs to switch between HW and SW interrupts Marc Zyngier
2020-02-20  3:55   ` Zenghui Yu
2020-02-28 19:16     ` Marc Zyngier
2020-03-02  2:40       ` Zenghui Yu
2020-02-14 14:57 ` [PATCH v4 17/20] KVM: arm64: GICv4.1: Plumb SGI implementation selection in the distributor Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 18/20] KVM: arm64: GICv4.1: Reload VLPI configuration on distributor enable/disable Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 19/20] KVM: arm64: GICv4.1: Allow non-trapping WFI when using HW SGIs Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 20/20] KVM: arm64: GICv4.1: Expose HW-based SGIs in debugfs Marc Zyngier

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