[PATCH 09/11] irqchip/gic-v3-its: Synchronise INT/CLEAR commands targetting a VLPI using VSYNC

Marc Zyngier
2019-11-05T16:23:26Z

We have so far always injected/cleared VLPIs using either
INT+SYNC or CLEAR+SYNC sequences, but that's pretty wrong
for two reasons:

- SYNC only synchronises physical LPIs
- The collection ID that for the associated LPI doesn't match
the redistributor the vPE is associated with

Instead, send an {INT,CLEAR}+VSYNC for forwarded LPIs, ensuring
that the ITS synchronises against the virtual pending table.

Reported-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
drivers/irqchip/irq-gic-v3-its.c | 79 ++++++++++++++++++++++++++++++--
1 file changed, 75 insertions(+), 4 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index d4b9f12e2e53..dbb994f52e42 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -718,6 +718,42 @@ static struct its_vpe *its_build_vinv_cmd(struct its_node *its,
return valid_vpe(its, map->vpe);
}

+static struct its_vpe *its_build_vint_cmd(struct its_node *its,
+ struct its_cmd_block *cmd,
+ struct its_cmd_desc *desc)
+{
+ struct its_vlpi_map *map;
+
+ map = dev_event_to_vlpi_map(desc->its_int_cmd.dev,
+ desc->its_int_cmd.event_id);
+
+ its_encode_cmd(cmd, GITS_CMD_INT);
+ its_encode_devid(cmd, desc->its_int_cmd.dev->device_id);
+ its_encode_event_id(cmd, desc->its_int_cmd.event_id);
+
+ its_fixup_cmd(cmd);
+
+ return valid_vpe(its, map->vpe);
+}
+
+static struct its_vpe *its_build_vclear_cmd(struct its_node *its,
+ struct its_cmd_block *cmd,
+ struct its_cmd_desc *desc)
+{
+ struct its_vlpi_map *map;
+
+ map = dev_event_to_vlpi_map(desc->its_clear_cmd.dev,
+ desc->its_clear_cmd.event_id);
+
+ its_encode_cmd(cmd, GITS_CMD_CLEAR);
+ its_encode_devid(cmd, desc->its_clear_cmd.dev->device_id);
+ its_encode_event_id(cmd, desc->its_clear_cmd.event_id);
+
+ its_fixup_cmd(cmd);
+
+ return valid_vpe(its, map->vpe);
+}
+
static u64 its_cmd_ptr_to_offset(struct its_node *its,
struct its_cmd_block *ptr)
{
@@ -1098,6 +1134,34 @@ static void its_send_vinv(struct its_device *dev, u32 event_id)
its_send_single_vcommand(dev->its, its_build_vinv_cmd, &desc);
}

+static void its_send_vint(struct its_device *dev, u32 event_id)
+{
+ struct its_cmd_desc desc;
+
+ /*
+ * There is no real VINT command. This is just a normal INT,
+ * with a VSYNC instead of a SYNC.
+ */
+ desc.its_int_cmd.dev = dev;
+ desc.its_int_cmd.event_id = event_id;
+
+ its_send_single_vcommand(dev->its, its_build_vint_cmd, &desc);
+}
+
+static void its_send_vclear(struct its_device *dev, u32 event_id)
+{
+ struct its_cmd_desc desc;
+
+ /*
+ * There is no real VCLEAR command. This is just a normal CLEAR,
+ * with a VSYNC instead of a SYNC.
+ */
+ desc.its_clear_cmd.dev = dev;
+ desc.its_clear_cmd.event_id = event_id;
+
+ its_send_single_vcommand(dev->its, its_build_vclear_cmd, &desc);
+}
+
/*
* irqchip functions - assumes MSI, mostly.
*/
@@ -1291,10 +1355,17 @@ static int its_irq_set_irqchip_state(struct irq_data *d,
if (which != IRQCHIP_STATE_PENDING)
return -EINVAL;

- if (state)
- its_send_int(its_dev, event);
- else
- its_send_clear(its_dev, event);
+ if (irqd_is_forwarded_to_vcpu(d)) {
+ if (state)
+ its_send_vint(its_dev, event);
+ else
+ its_send_vclear(its_dev, event);
+ } else {
+ if (state)
+ its_send_int(its_dev, event);
+ else
+ its_send_clear(its_dev, event);
+ }

return 0;
}
--
2.20.1