[PATCH v3 20/59] irqchip/gic-v3-its: Add VPE irq domain allocation/teardown

Marc Zyngier
2017-07-31T17:26:18Z

When creating a VM, the low level GICv4 code is responsible for:
- allocating each VPE a unique VPEID
- allocating a doorbell interrupt for each VPE
- allocating the pending tables for each VPE
- allocating the property table for the VM

This of course has to be reversed when the VM is brought down.

All of this is wired into the irq domain alloc/free methods.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
drivers/irqchip/irq-gic-v3-its.c | 169 +++++++++++++++++++++++++++++++++++++++
1 file changed, 169 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 1fa345d53088..0f9a487448b9 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -148,6 +148,7 @@ static struct irq_domain *its_parent;
#define ITS_LIST_MAX 16

static unsigned long its_list_map;
+static DEFINE_IDA(its_vpeid_ida);

#define gic_data_rdist() (raw_cpu_ptr(gic_rdists->rdist))
#define gic_data_rdist_rd_base() (gic_data_rdist()->rd_base)
@@ -1249,6 +1250,11 @@ static struct page *its_allocate_prop_table(gfp_t gfp_flags)
return prop_page;
}

+static void its_free_prop_table(struct page *prop_page)
+{
+ free_pages((unsigned long)page_address(prop_page),
+ get_order(LPI_PROPBASE_SZ));
+}

static int __init its_alloc_lpi_tables(void)
{
@@ -1551,6 +1557,12 @@ static struct page *its_allocate_pending_table(gfp_t gfp_flags)
return pend_page;
}

+static void its_free_pending_table(struct page *pt)
+{
+ free_pages((unsigned long)page_address(pt),
+ get_order(max_t(u32, LPI_PENDBASE_SZ, SZ_64K)));
+}
+
static void its_cpu_init_lpis(void)
{
void __iomem *rbase = gic_data_rdist_rd_base();
@@ -1773,6 +1785,34 @@ static bool its_alloc_device_table(struct its_node *its, u32 dev_id)
return its_alloc_table_entry(baser, dev_id);
}

+static bool its_alloc_vpe_table(u32 vpe_id)
+{
+ struct its_node *its;
+
+ /*
+ * Make sure the L2 tables are allocated on *all* v4 ITSs. We
+ * could try and only do it on ITSs corresponding to devices
+ * that have interrupts targeted at this VPE, but the
+ * complexity becomes crazy (and you have tons of memory
+ * anyway, right?).
+ */
+ list_for_each_entry(its, &its_nodes, entry) {
+ struct its_baser *baser;
+
+ if (!its->is_v4)
+ continue;
+
+ baser = its_get_baser(its, GITS_BASER_TYPE_VCPU);
+ if (!baser)
+ return false;
+
+ if (!its_alloc_table_entry(baser, vpe_id))
+ return false;
+ }
+
+ return true;
+}
+
static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
int nvecs)
{
@@ -2030,7 +2070,136 @@ static struct irq_chip its_vpe_irq_chip = {
.name = "GICv4-vpe",
};

+static int its_vpe_id_alloc(void)
+{
+ return ida_simple_get(&its_vpeid_ida, 0, 1 << 16, GFP_KERNEL);
+}
+
+static void its_vpe_id_free(u16 id)
+{
+ ida_simple_remove(&its_vpeid_ida, id);
+}
+
+static int its_vpe_init(struct its_vpe *vpe)
+{
+ struct page *vpt_page;
+ int vpe_id;
+
+ /* Allocate vpe_id */
+ vpe_id = its_vpe_id_alloc();
+ if (vpe_id < 0)
+ return vpe_id;
+
+ /* Allocate VPT */
+ vpt_page = its_allocate_pending_table(GFP_KERNEL);
+ if (!vpt_page) {
+ its_vpe_id_free(vpe_id);
+ return -ENOMEM;
+ }
+
+ if (!its_alloc_vpe_table(vpe_id)) {
+ its_vpe_id_free(vpe_id);
+ its_free_pending_table(vpe->vpt_page);
+ return -ENOMEM;
+ }
+
+ vpe->vpe_id = vpe_id;
+ vpe->vpt_page = vpt_page;
+
+ return 0;
+}
+
+static void its_vpe_teardown(struct its_vpe *vpe)
+{
+ its_vpe_id_free(vpe->vpe_id);
+ its_free_pending_table(vpe->vpt_page);
+}
+
+static void its_vpe_irq_domain_free(struct irq_domain *domain,
+ unsigned int virq,
+ unsigned int nr_irqs)
+{
+ struct its_vm *vm = domain->host_data;
+ int i;
+
+ irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+
+ for (i = 0; i < nr_irqs; i++) {
+ struct irq_data *data = irq_domain_get_irq_data(domain,
+ virq + i);
+ struct its_vpe *vpe = irq_data_get_irq_chip_data(data);
+
+ BUG_ON(vm != vpe->its_vm);
+
+ clear_bit(data->hwirq, vm->db_bitmap);
+ its_vpe_teardown(vpe);
+ irq_domain_reset_irq_data(data);
+ }
+
+ if (bitmap_empty(vm->db_bitmap, vm->nr_db_lpis)) {
+ its_lpi_free_chunks(vm->db_bitmap, vm->db_lpi_base, vm->nr_db_lpis);
+ its_free_prop_table(vm->vprop_page);
+ }
+}
+
+static int its_vpe_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
+ unsigned int nr_irqs, void *args)
+{
+ struct its_vm *vm = args;
+ unsigned long *bitmap;
+ struct page *vprop_page;
+ int base, nr_ids, i, err = 0;
+
+ BUG_ON(!vm);
+
+ bitmap = its_lpi_alloc_chunks(nr_irqs, &base, &nr_ids);
+ if (!bitmap)
+ return -ENOMEM;
+
+ if (nr_ids < nr_irqs) {
+ its_lpi_free_chunks(bitmap, base, nr_ids);
+ return -ENOMEM;
+ }
+
+ vprop_page = its_allocate_prop_table(GFP_KERNEL);
+ if (!vprop_page) {
+ its_lpi_free_chunks(bitmap, base, nr_ids);
+ return -ENOMEM;
+ }
+
+ vm->db_bitmap = bitmap;
+ vm->db_lpi_base = base;
+ vm->nr_db_lpis = nr_ids;
+ vm->vprop_page = vprop_page;
+
+ for (i = 0; i < nr_irqs; i++) {
+ vm->vpes[i]->vpe_db_lpi = base + i;
+ err = its_vpe_init(vm->vpes[i]);
+ if (err)
+ break;
+ err = its_irq_gic_domain_alloc(domain, virq + i,
+ vm->vpes[i]->vpe_db_lpi);
+ if (err)
+ break;
+ irq_domain_set_hwirq_and_chip(domain, virq + i, i,
+ &its_vpe_irq_chip, vm->vpes[i]);
+ set_bit(i, bitmap);
+ }
+
+ if (err) {
+ if (i > 0)
+ its_vpe_irq_domain_free(domain, virq, i - 1);
+
+ its_lpi_free_chunks(bitmap, base, nr_ids);
+ its_free_prop_table(vprop_page);
+ }
+
+ return err;
+}
+
static const struct irq_domain_ops its_vpe_domain_ops = {
+ .alloc = its_vpe_irq_domain_alloc,
+ .free = its_vpe_irq_domain_free,
};

static int its_force_quiescent(void __iomem *base)
--
2.11.0