irqchip/gicv3-its: Fix mapping of LPIs to collections

The GICv3 ITS architecture allows a given [DevID, EventID] pair to be
translated to a [LPI, Collection] pair, where DevID is the device writing
the MSI, EventID is the payload being written, LPI is the actual
interrupt number, and Collection is roughly equivalent to a target CPU.

Each LPI can be mapped to a separate collection, but the ITS driver
insists on maintaining the collection on a device basis, instead of doing
it on a per interrupt basis.

This is obviously flawed, and this patch fixes it by adding a per interrupt
index that indicates which collection number is in use.

Reported-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: stable@vger.kernel.org	# 4.1, 4.0
Link: http://lkml.kernel.org/r/1437126402-11677-1-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 1b7e155869f6c1a5f9ff361f246b6fd71539dadc..c00e2db351ba5aec327ebb1e98085b25b9b4d056 100644 (file)
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -75,6 +75,13 @@ struct its_node {
 
 #define ITS_ITT_ALIGN          SZ_256
 
+struct event_lpi_map {
+       unsigned long           *lpi_map;
+       u16                     *col_map;
+       irq_hw_number_t         lpi_base;
+       int                     nr_lpis;
+};
+
 /*
  * The ITS view of a device - belongs to an ITS, a collection, owns an
  * interrupt translation table, and a list of interrupts.
@@ -82,11 +89,8 @@ struct its_node {
 struct its_device {
        struct list_head        entry;
        struct its_node         *its;
-       struct its_collection   *collection;
+       struct event_lpi_map    event_map;
        void                    *itt;
-       unsigned long           *lpi_map;
-       irq_hw_number_t         lpi_base;
-       int                     nr_lpis;
        u32                     nr_ites;
        u32                     device_id;
 };
@@ -99,6 +103,14 @@ static struct rdists *gic_rdists;
 #define gic_data_rdist()               (raw_cpu_ptr(gic_rdists->rdist))
 #define gic_data_rdist_rd_base()       (gic_data_rdist()->rd_base)
 
+static struct its_collection *dev_event_to_col(struct its_device *its_dev,
+                                              u32 event)
+{
+       struct its_node *its = its_dev->its;
+
+       return its->collections + its_dev->event_map.col_map[event];
+}
+
 /*
  * ITS command descriptors - parameters to be encoded in a command
  * block.
@@ -134,7 +146,7 @@ struct its_cmd_desc {
                struct {
                        struct its_device *dev;
                        struct its_collection *col;
-                       u32 id;
+                       u32 event_id;
                } its_movi_cmd;
 
                struct {
@@ -241,7 +253,7 @@ static struct its_collection *its_build_mapd_cmd(struct its_cmd_block *cmd,
 
        its_fixup_cmd(cmd);
 
-       return desc->its_mapd_cmd.dev->collection;
+       return NULL;
 }
 
 static struct its_collection *its_build_mapc_cmd(struct its_cmd_block *cmd,
@@ -260,52 +272,72 @@ static struct its_collection *its_build_mapc_cmd(struct its_cmd_block *cmd,
 static struct its_collection *its_build_mapvi_cmd(struct its_cmd_block *cmd,
                                                  struct its_cmd_desc *desc)
 {
+       struct its_collection *col;
+
+       col = dev_event_to_col(desc->its_mapvi_cmd.dev,
+                              desc->its_mapvi_cmd.event_id);
+
        its_encode_cmd(cmd, GITS_CMD_MAPVI);
        its_encode_devid(cmd, desc->its_mapvi_cmd.dev->device_id);
        its_encode_event_id(cmd, desc->its_mapvi_cmd.event_id);
        its_encode_phys_id(cmd, desc->its_mapvi_cmd.phys_id);
-       its_encode_collection(cmd, desc->its_mapvi_cmd.dev->collection->col_id);
+       its_encode_collection(cmd, col->col_id);
 
        its_fixup_cmd(cmd);
 
-       return desc->its_mapvi_cmd.dev->collection;
+       return col;
 }
 
 static struct its_collection *its_build_movi_cmd(struct its_cmd_block *cmd,
                                                 struct its_cmd_desc *desc)
 {
+       struct its_collection *col;
+
+       col = dev_event_to_col(desc->its_movi_cmd.dev,
+                              desc->its_movi_cmd.event_id);
+
        its_encode_cmd(cmd, GITS_CMD_MOVI);
        its_encode_devid(cmd, desc->its_movi_cmd.dev->device_id);
-       its_encode_event_id(cmd, desc->its_movi_cmd.id);
+       its_encode_event_id(cmd, desc->its_movi_cmd.event_id);
        its_encode_collection(cmd, desc->its_movi_cmd.col->col_id);
 
        its_fixup_cmd(cmd);
 
-       return desc->its_movi_cmd.dev->collection;
+       return col;
 }
 
 static struct its_collection *its_build_discard_cmd(struct its_cmd_block *cmd,
                                                    struct its_cmd_desc *desc)
 {
+       struct its_collection *col;
+
+       col = dev_event_to_col(desc->its_discard_cmd.dev,
+                              desc->its_discard_cmd.event_id);
+
        its_encode_cmd(cmd, GITS_CMD_DISCARD);
        its_encode_devid(cmd, desc->its_discard_cmd.dev->device_id);
        its_encode_event_id(cmd, desc->its_discard_cmd.event_id);
 
        its_fixup_cmd(cmd);
 
-       return desc->its_discard_cmd.dev->collection;
+       return col;
 }
 
 static struct its_collection *its_build_inv_cmd(struct its_cmd_block *cmd,
                                                struct its_cmd_desc *desc)
 {
+       struct its_collection *col;
+
+       col = dev_event_to_col(desc->its_inv_cmd.dev,
+                              desc->its_inv_cmd.event_id);
+
        its_encode_cmd(cmd, GITS_CMD_INV);
        its_encode_devid(cmd, desc->its_inv_cmd.dev->device_id);
        its_encode_event_id(cmd, desc->its_inv_cmd.event_id);
 
        its_fixup_cmd(cmd);
 
-       return desc->its_inv_cmd.dev->collection;
+       return col;
 }
 
 static struct its_collection *its_build_invall_cmd(struct its_cmd_block *cmd,
@@ -497,7 +529,7 @@ static void its_send_movi(struct its_device *dev,
 
        desc.its_movi_cmd.dev = dev;
        desc.its_movi_cmd.col = col;
-       desc.its_movi_cmd.id = id;
+       desc.its_movi_cmd.event_id = id;
 
        its_send_single_command(dev->its, its_build_movi_cmd, &desc);
 }
@@ -528,7 +560,7 @@ static void its_send_invall(struct its_node *its, struct its_collection *col)
 static inline u32 its_get_event_id(struct irq_data *d)
 {
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
-       return d->hwirq - its_dev->lpi_base;
+       return d->hwirq - its_dev->event_map.lpi_base;
 }
 
 static void lpi_set_config(struct irq_data *d, bool enable)
@@ -583,7 +615,7 @@ static int its_set_affinity(struct irq_data *d, const struct cpumask *mask_val,
 
        target_col = &its_dev->its->collections[cpu];
        its_send_movi(its_dev, target_col, id);
-       its_dev->collection = target_col;
+       its_dev->event_map.col_map[id] = cpu;
 
        return IRQ_SET_MASK_OK_DONE;
 }
@@ -713,8 +745,10 @@ out:
        return bitmap;
 }
 
-static void its_lpi_free(unsigned long *bitmap, int base, int nr_ids)
+static void its_lpi_free(struct event_lpi_map *map)
 {
+       int base = map->lpi_base;
+       int nr_ids = map->nr_lpis;
        int lpi;
 
        spin_lock(&lpi_lock);
@@ -731,7 +765,8 @@ static void its_lpi_free(unsigned long *bitmap, int base, int nr_ids)
 
        spin_unlock(&lpi_lock);
 
-       kfree(bitmap);
+       kfree(map->lpi_map);
+       kfree(map->col_map);
 }
 
 /*
@@ -1099,11 +1134,11 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
        struct its_device *dev;
        unsigned long *lpi_map;
        unsigned long flags;
+       u16 *col_map = NULL;
        void *itt;
        int lpi_base;
        int nr_lpis;
        int nr_ites;
-       int cpu;
        int sz;
 
        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
@@ -1117,20 +1152,24 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
        sz = max(sz, ITS_ITT_ALIGN) + ITS_ITT_ALIGN - 1;
        itt = kzalloc(sz, GFP_KERNEL);
        lpi_map = its_lpi_alloc_chunks(nvecs, &lpi_base, &nr_lpis);
+       if (lpi_map)
+               col_map = kzalloc(sizeof(*col_map) * nr_lpis, GFP_KERNEL);
 
-       if (!dev || !itt || !lpi_map) {
+       if (!dev || !itt || !lpi_map || !col_map) {
                kfree(dev);
                kfree(itt);
                kfree(lpi_map);
+               kfree(col_map);
                return NULL;
        }
 
        dev->its = its;
        dev->itt = itt;
        dev->nr_ites = nr_ites;
-       dev->lpi_map = lpi_map;
-       dev->lpi_base = lpi_base;
-       dev->nr_lpis = nr_lpis;
+       dev->event_map.lpi_map = lpi_map;
+       dev->event_map.col_map = col_map;
+       dev->event_map.lpi_base = lpi_base;
+       dev->event_map.nr_lpis = nr_lpis;
        dev->device_id = dev_id;
        INIT_LIST_HEAD(&dev->entry);
 
@@ -1138,10 +1177,6 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
        list_add(&dev->entry, &its->its_device_list);
        raw_spin_unlock_irqrestore(&its->lock, flags);
 
-       /* Bind the device to the first possible CPU */
-       cpu = cpumask_first(cpu_online_mask);
-       dev->collection = &its->collections[cpu];
-
        /* Map device to its ITT */
        its_send_mapd(dev, 1);
 
@@ -1163,12 +1198,13 @@ static int its_alloc_device_irq(struct its_device *dev, irq_hw_number_t *hwirq)
 {
        int idx;
 
-       idx = find_first_zero_bit(dev->lpi_map, dev->nr_lpis);
-       if (idx == dev->nr_lpis)
+       idx = find_first_zero_bit(dev->event_map.lpi_map,
+                                 dev->event_map.nr_lpis);
+       if (idx == dev->event_map.nr_lpis)
                return -ENOSPC;
 
-       *hwirq = dev->lpi_base + idx;
-       set_bit(idx, dev->lpi_map);
+       *hwirq = dev->event_map.lpi_base + idx;
+       set_bit(idx, dev->event_map.lpi_map);
 
        return 0;
 }
@@ -1288,7 +1324,8 @@ static int its_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
                irq_domain_set_hwirq_and_chip(domain, virq + i,
                                              hwirq, &its_irq_chip, its_dev);
                dev_dbg(info->scratchpad[1].ptr, "ID:%d pID:%d vID:%d\n",
-                       (int)(hwirq - its_dev->lpi_base), (int)hwirq, virq + i);
+                       (int)(hwirq - its_dev->event_map.lpi_base),
+                       (int)hwirq, virq + i);
        }
 
        return 0;
@@ -1300,6 +1337,9 @@ static void its_irq_domain_activate(struct irq_domain *domain,
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
        u32 event = its_get_event_id(d);
 
+       /* Bind the LPI to the first possible CPU */
+       its_dev->event_map.col_map[event] = cpumask_first(cpu_online_mask);
+
        /* Map the GIC IRQ and event to the device */
        its_send_mapvi(its_dev, d->hwirq, event);
 }
@@ -1327,17 +1367,16 @@ static void its_irq_domain_free(struct irq_domain *domain, unsigned int virq,
                u32 event = its_get_event_id(data);
 
                /* Mark interrupt index as unused */
-               clear_bit(event, its_dev->lpi_map);
+               clear_bit(event, its_dev->event_map.lpi_map);
 
                /* Nuke the entry in the domain */
                irq_domain_reset_irq_data(data);
        }
 
        /* If all interrupts have been freed, start mopping the floor */
-       if (bitmap_empty(its_dev->lpi_map, its_dev->nr_lpis)) {
-               its_lpi_free(its_dev->lpi_map,
-                            its_dev->lpi_base,
-                            its_dev->nr_lpis);
+       if (bitmap_empty(its_dev->event_map.lpi_map,
+                        its_dev->event_map.nr_lpis)) {
+               its_lpi_free(&its_dev->event_map);
 
                /* Unmap device/itt */
                its_send_mapd(its_dev, 0);