Re: [PATCH v5 08/23] irqchip/gic-v4.1: Plumb skeletal VSGI irqchip

Marc Zyngier
2020-03-19T10:03:26Z

Hi Eric,

On 2020-03-16 17:10, Auger Eric wrote:
> Hi Marc,
>
> On 3/4/20 9:33 PM, Marc Zyngier wrote:
>> Since GICv4.1 has the capability to inject 16 SGIs into each VPE,
>> and that I'm keen not to invent too many specific interfaces to
>> manipulate these interrupts, let's pretend that each of these SGIs
>> is an actual Linux interrupt.
>>
>> For that matter, let's introduce a minimal irqchip and irqdomain
>> setup that will get fleshed up in the following patches.
>>
>> Signed-off-by: Marc Zyngier <maz@kernel.org>
>> Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
>> ---
>> drivers/irqchip/irq-gic-v3-its.c | 68
>> +++++++++++++++++++++++++++++-
>> drivers/irqchip/irq-gic-v4.c | 8 +++-
>> include/linux/irqchip/arm-gic-v4.h | 9 +++-
>> 3 files changed, 81 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/irqchip/irq-gic-v3-its.c
>> b/drivers/irqchip/irq-gic-v3-its.c
>> index 54d6fdf7a28e..112b452fcb40 100644
>> --- a/drivers/irqchip/irq-gic-v3-its.c
>> +++ b/drivers/irqchip/irq-gic-v3-its.c
>> @@ -3870,6 +3870,67 @@ static struct irq_chip its_vpe_4_1_irq_chip = {
>> .irq_set_vcpu_affinity = its_vpe_4_1_set_vcpu_affinity,
>> };
>>
>> +static int its_sgi_set_affinity(struct irq_data *d,
>> + const struct cpumask *mask_val,
>> + bool force)
>> +{
>> + return -EINVAL;
>> +}
>> +
>> +static struct irq_chip its_sgi_irq_chip = {
>> + .name = "GICv4.1-sgi",
>> + .irq_set_affinity = its_sgi_set_affinity,
>> +};
> nit: const?

That would create a warning with irq_domain_set_hwirq_and_chip(), which
doesn't take a const argument. I think this is fixable in the long run,
but only as a sweeping tree-wide change.

>> +
>> +static int its_sgi_irq_domain_alloc(struct irq_domain *domain,
>> + unsigned int virq, unsigned int nr_irqs,
>> + void *args)
>> +{
>> + struct its_vpe *vpe = args;
>> + int i;
>> +
>> + /* Yes, we do want 16 SGIs */
>> + WARN_ON(nr_irqs != 16);
>> +
>> + for (i = 0; i < 16; i++) {
>> + vpe->sgi_config[i].priority = 0;
>> + vpe->sgi_config[i].enabled = false;
>> + vpe->sgi_config[i].group = false;
>> +
>> + irq_domain_set_hwirq_and_chip(domain, virq + i, i,
>> + &its_sgi_irq_chip, vpe);
>> + irq_set_status_flags(virq + i, IRQ_DISABLE_UNLAZY);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static void its_sgi_irq_domain_free(struct irq_domain *domain,
>> + unsigned int virq,
>> + unsigned int nr_irqs)
>> +{
>> + /* Nothing to do */
>> +}
>> +
>> +static int its_sgi_irq_domain_activate(struct irq_domain *domain,
>> + struct irq_data *d, bool reserve)
>> +{
>> + return 0;
>> +}
>> +
>> +static void its_sgi_irq_domain_deactivate(struct irq_domain *domain,
>> + struct irq_data *d)
>> +{
>> + /* Nothing to do */
>> +}
>> +
>> +static struct irq_domain_ops its_sgi_domain_ops = {
>> + .alloc = its_sgi_irq_domain_alloc,
>> + .free = its_sgi_irq_domain_free,
>> + .activate = its_sgi_irq_domain_activate,
>> + .deactivate = its_sgi_irq_domain_deactivate,
>> +};
> nit: const?

This one can work with a bit of surgery below:

diff --git a/drivers/irqchip/irq-gic-v3-its.c
b/drivers/irqchip/irq-gic-v3-its.c
index 2e12bc52e3a2..321f73015d6c 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -4129,7 +4129,7 @@ static void its_sgi_irq_domain_deactivate(struct
irq_domain *domain,
its_configure_sgi(d, true);
}

-static struct irq_domain_ops its_sgi_domain_ops = {
+static const struct irq_domain_ops its_sgi_domain_ops = {
.alloc = its_sgi_irq_domain_alloc,
.free = its_sgi_irq_domain_free,
.activate = its_sgi_irq_domain_activate,
@@ -5182,10 +5182,12 @@ int __init its_init(struct fwnode_handle
*handle, struct rdists *rdists,
rdists->has_rvpeid = false;

if (has_v4 & rdists->has_vlpis) {
- struct irq_domain_ops *sgi_ops = NULL;
+ const struct irq_domain_ops *sgi_ops;

if (has_v4_1)
sgi_ops = &its_sgi_domain_ops;
+ else
+ sgi_ops = NULL;

if (its_init_vpe_domain() ||
its_init_v4(parent_domain, &its_vpe_domain_ops, sgi_ops)) {

>> +
>> static int its_vpe_id_alloc(void)
>> {
>> return ida_simple_get(&its_vpeid_ida, 0, ITS_MAX_VPEID, GFP_KERNEL);
>> @@ -4912,8 +4973,13 @@ int __init its_init(struct fwnode_handle
>> *handle, struct rdists *rdists,
>> rdists->has_rvpeid = false;
>>
>> if (has_v4 & rdists->has_vlpis) {
>> + struct irq_domain_ops *sgi_ops = NULL;
>> +
>> + if (has_v4_1)
>> + sgi_ops = &its_sgi_domain_ops;
>> +
>> if (its_init_vpe_domain() ||
>> - its_init_v4(parent_domain, &its_vpe_domain_ops)) {
>> + its_init_v4(parent_domain, &its_vpe_domain_ops, sgi_ops)) {
>> rdists->has_vlpis = false;
>> pr_err("ITS: Disabling GICv4 support\n");
>> }
>> diff --git a/drivers/irqchip/irq-gic-v4.c
>> b/drivers/irqchip/irq-gic-v4.c
>> index 45969927cc81..c01910d53f9e 100644
>> --- a/drivers/irqchip/irq-gic-v4.c
>> +++ b/drivers/irqchip/irq-gic-v4.c
>> @@ -85,6 +85,7 @@
>>
>> static struct irq_domain *gic_domain;
>> static const struct irq_domain_ops *vpe_domain_ops;
>> +static const struct irq_domain_ops *sgi_domain_ops;
>>
>> int its_alloc_vcpu_irqs(struct its_vm *vm)
>> {
>> @@ -216,12 +217,15 @@ int its_prop_update_vlpi(int irq, u8 config,
>> bool inv)
>> return irq_set_vcpu_affinity(irq, &info);
>> }
>>
>> -int its_init_v4(struct irq_domain *domain, const struct
>> irq_domain_ops *ops)
>> +int its_init_v4(struct irq_domain *domain,
>> + const struct irq_domain_ops *vpe_ops,
>> + const struct irq_domain_ops *sgi_ops)
>> {
>> if (domain) {
>> pr_info("ITS: Enabling GICv4 support\n");
>> gic_domain = domain;
>> - vpe_domain_ops = ops;
>> + vpe_domain_ops = vpe_ops;
>> + sgi_domain_ops = sgi_ops;
>> return 0;
>> }
>>
>> diff --git a/include/linux/irqchip/arm-gic-v4.h
>> b/include/linux/irqchip/arm-gic-v4.h
>> index 439963f4c66a..44e8c19e3d56 100644
>> --- a/include/linux/irqchip/arm-gic-v4.h
>> +++ b/include/linux/irqchip/arm-gic-v4.h
>> @@ -49,6 +49,11 @@ struct its_vpe {
>> };
>> /* GICv4.1 implementations */
>> struct {
>> + struct {
>> + u8 priority;
>> + bool enabled;
>> + bool group;
>> + } sgi_config[16];
>> atomic_t vmapp_count;
>> };
>> };
>> @@ -123,6 +128,8 @@ int its_unmap_vlpi(int irq);
>> int its_prop_update_vlpi(int irq, u8 config, bool inv);
>>
>> struct irq_domain_ops;
>> -int its_init_v4(struct irq_domain *domain, const struct
>> irq_domain_ops *ops);
>> +int its_init_v4(struct irq_domain *domain,
>> + const struct irq_domain_ops *vpe_ops,
>> + const struct irq_domain_ops *sgi_ops);
>>
>> #endif
>>
> Reviewed-by: Eric Auger <eric.auger@redhat.com>

Thanks,

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