Marc,
On 04/20/2016 11:27 AM, Marc Zyngier wrote:
> On 19/04/16 18:13, Eric Auger wrote:
>> This patch implements the msi_doorbell_info callback in the
>> gicv2m driver.
>>
>> The driver now is able to return its doorbell characteristics
>> (base, size, prot). A single doorbell is exposed.
>>
>> This will allow the msi layer to iommu_map this doorbell when
>> requested.
>>
>> Signed-off-by: Eric Auger <eric.au...@linaro.org>
>>
>> ---
>>
>> v7: creation
>> ---
>> drivers/irqchip/irq-gic-v2m.c | 32 +++++++++++++++++++++++++++++++-
>> 1 file changed, 31 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/irqchip/irq-gic-v2m.c b/drivers/irqchip/irq-gic-v2m.c
>> index 28f047c..54690b9 100644
>> --- a/drivers/irqchip/irq-gic-v2m.c
>> +++ b/drivers/irqchip/irq-gic-v2m.c
>> @@ -24,6 +24,8 @@
>> #include <linux/of_pci.h>
>> #include <linux/slab.h>
>> #include <linux/spinlock.h>
>> +#include <linux/percpu.h>
>> +#include <linux/iommu.h>
>>
>> /*
>> * MSI_TYPER:
>> @@ -64,6 +66,7 @@ struct v2m_data {
>> u32 nr_spis; /* The number of SPIs for MSIs */
>> unsigned long *bm; /* MSI vector bitmap */
>> u32 flags; /* v2m flags for specific implementation */
>> + struct irq_chip_msi_doorbell_info doorbell_info;
>> };
>>
>> static void gicv2m_mask_msi_irq(struct irq_data *d)
>> @@ -105,6 +108,16 @@ static void gicv2m_compose_msi_msg(struct irq_data
>> *data, struct msi_msg *msg)
>> msg->data -= v2m->spi_start;
>> }
>>
>> +static const struct irq_chip_msi_doorbell_info *
>> +gicv2m_msi_doorbell_info(struct irq_data *data)
>> +{
>> + struct v2m_data *v2m = irq_data_get_irq_chip_data(data);
>> +
>> + if (!v2m)
>> + return NULL;
>
> How can this ever be NULL? I think you can drop that test.
OK
>
>> + return (const struct irq_chip_msi_doorbell_info *)(&v2m->doorbell_info);
>
> Please don't do that. Use "const" in the functions that are using
> irq_chip_msi_doorbell_info, but do not make this "const" here.
It definitively compiles without casting so obviously this is not needed
but is there any other wrong thing I don't see?
we still want this function to return a pointer to a const?
>
>> +}
>> +
>> static struct irq_chip gicv2m_irq_chip = {
>> .name = "GICv2m",
>> .irq_mask = irq_chip_mask_parent,
>> @@ -112,6 +125,7 @@ static struct irq_chip gicv2m_irq_chip = {
>> .irq_eoi = irq_chip_eoi_parent,
>> .irq_set_affinity = irq_chip_set_affinity_parent,
>> .irq_compose_msi_msg = gicv2m_compose_msi_msg,
>> + .msi_doorbell_info = gicv2m_msi_doorbell_info,
>> };
>>
>> static int gicv2m_irq_gic_domain_alloc(struct irq_domain *domain,
>> @@ -247,6 +261,7 @@ static void gicv2m_teardown(void)
>>
>> list_for_each_entry_safe(v2m, tmp, &v2m_nodes, entry) {
>> list_del(&v2m->entry);
>> + free_percpu(v2m->doorbell_info.percpu_doorbells);
>> kfree(v2m->bm);
>> iounmap(v2m->base);
>> of_node_put(to_of_node(v2m->fwnode));
>> @@ -299,6 +314,7 @@ static int __init gicv2m_init_one(struct fwnode_handle
>> *fwnode,
>> {
>> int ret;
>> struct v2m_data *v2m;
>> + struct irq_chip_msi_doorbell __percpu *doorbell;
>>
>> v2m = kzalloc(sizeof(struct v2m_data), GFP_KERNEL);
>> if (!v2m) {
>> @@ -311,11 +327,23 @@ static int __init gicv2m_init_one(struct fwnode_handle
>> *fwnode,
>>
>> memcpy(&v2m->res, res, sizeof(struct resource));
>>
>> + v2m->doorbell_info.percpu_doorbells =
>> + alloc_percpu(struct irq_chip_msi_doorbell);
>> + if (WARN_ON(!v2m->doorbell_info.percpu_doorbells)) {
>> + ret = -ENOMEM;
>> + goto err_free_v2m;
>> + }
>> + doorbell = per_cpu_ptr(v2m->doorbell_info.percpu_doorbells, 0);
>> + doorbell->base = v2m->res.start;
>> + doorbell->size = 4;
>> + doorbell->prot = IOMMU_WRITE;
>
> You probably need to also have something that says IOMMU_DEVICE or
> something similar, because I'm afraid you're getting a memory mapping
> here. I've had a quick look at the two other series, but couldn't find
> anything that would force the memory attributes.
Yes you're right I currently just enforce the direction (which is
checked against what VFIO user registered). Do you refer to IOMMU_MMIO,
latterly proposed on the ML. In the positive, yes I intend to add it
once it gets upstreamed.
Thanks
Eric
>
>> + v2m->doorbell_info.nb_doorbells = 1;
>> +
>> v2m->base = ioremap(v2m->res.start, resource_size(&v2m->res));
>> if (!v2m->base) {
>> pr_err("Failed to map GICv2m resource\n");
>> ret = -ENOMEM;
>> - goto err_free_v2m;
>> + goto err_free_v2m_doorbells;
>> }
>>
>> if (spi_start && nr_spis) {
>> @@ -359,6 +387,8 @@ static int __init gicv2m_init_one(struct fwnode_handle
>> *fwnode,
>>
>> err_iounmap:
>> iounmap(v2m->base);
>> +err_free_v2m_doorbells:
>> + free_percpu(v2m->doorbell_info.percpu_doorbells);
>> err_free_v2m:
>> kfree(v2m);
>> return ret;
>>
>
> Thanks,
>
> M.
>
