irqchip/gic-v3-its: Add VPE irq domain allocation/teardown

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>

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 0de4a54485e83dc15880a55cd0621913d81dceca..06ec47f004f99b06d04659971721eab471db5bd1 100644 (file)
--- 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)
@@ -1255,6 +1256,11 @@ 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)
 {
@@ -1557,6 +1563,12 @@ 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();
@@ -1779,6 +1791,34 @@ 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)
 {
@@ -2036,7 +2076,136 @@ 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)