[RFC 17/17] VFIO: platform: add irq bypass producer management

Eric Auger
2015-07-02T13:19:57Z

This patch adds irq_bypass_producer registration/unregistration.
VFIO producer callbacks are populated:
- stop/resume producer simply consist in disabling/enabling the host irq
- add/del consumer: basically set the automasked flag to false/true

The vfio_platform_device pointer is passed as producer opaque.

We also cache the device handle in vfio_platform_device. This
makes possible to easily retrieve the vfio_device at registration.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
---
drivers/vfio/platform/vfio_platform_common.c | 2 +
drivers/vfio/platform/vfio_platform_irq.c | 83 +++++++++++++++++++++++++++
drivers/vfio/platform/vfio_platform_private.h | 2 +
3 files changed, 87 insertions(+)

diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index 9acfca6..12d4540 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -546,6 +546,8 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
if (!vdev)
return -EINVAL;

+ vdev->dev = dev;
+
group = iommu_group_get(dev);
if (!group) {
pr_err("VFIO: No IOMMU group for device %s\n", vdev->name);
diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
index f6d83ed..0061e6e 100644
--- a/drivers/vfio/platform/vfio_platform_irq.c
+++ b/drivers/vfio/platform/vfio_platform_irq.c
@@ -20,6 +20,7 @@
#include <linux/types.h>
#include <linux/vfio.h>
#include <linux/irq.h>
+#include <linux/irqbypass.h>

#include "vfio_platform_private.h"

@@ -185,6 +186,70 @@ static irqreturn_t vfio_handler(int irq, void *dev_id)
return ret;
}

+static void vfio_platform_stop_producer(struct irq_bypass_producer *prod)
+{
+ pr_info("%s disable %d\n", __func__, prod->irq);
+ disable_irq(prod->irq);
+}
+
+static void vfio_platform_resume_producer(struct irq_bypass_producer *prod)
+{
+ pr_info("%s enable %d\n", __func__, prod->irq);
+ enable_irq(prod->irq);
+}
+
+static void vfio_platform_add_consumer(struct irq_bypass_producer *prod,
+ struct irq_bypass_consumer *cons)
+{
+ int i, ret;
+ struct vfio_platform_device *vdev =
+ (struct vfio_platform_device *)prod->opaque;
+
+ pr_info("%s irq=%d gsi =%d\n", __func__, prod->irq, cons->gsi);
+
+ for (i = 0; i < vdev->num_irqs; i++) {
+ if (vdev->irqs[i].prod == prod)
+ break;
+ }
+ WARN_ON(i == vdev->num_irqs);
+
+ //TODO
+ /*
+ * if the IRQ is active at irqchip level or VFIO (auto)masked
+ * this means the host IRQ is already under injection in the
+ * guest and this not safe to change the forwarding state at
+ * that stage.
+ * It is not possible to differentiate user-space masking
+ * from auto-masking, leading to possible false detection of
+ * active state.
+ */
+ prod->active = vfio_external_is_active(prod->vdev, i, 0, 0);
+
+ ret = vfio_external_set_automasked(prod->vdev, i, 0, 0, false);
+ WARN_ON(ret);
+}
+
+static void vfio_platform_del_consumer(struct irq_bypass_producer *prod,
+ struct irq_bypass_consumer *cons)
+{
+ int i;
+ struct vfio_platform_device *vdev =
+ (struct vfio_platform_device *)prod->opaque;
+
+ pr_info("%s irq=%d gsi =%d\n", __func__, prod->irq, cons->gsi);
+
+ for (i = 0; i < vdev->num_irqs; i++) {
+ if (vdev->irqs[i].prod == prod)
+ break;
+ }
+ WARN_ON(i == vdev->num_irqs);
+
+ if (prod->active)
+ vfio_external_mask(prod->vdev, i, 0, 0);
+
+ vfio_external_set_automasked(prod->vdev, i, 0, 0, true);
+}
+
static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
int fd, irq_handler_t handler)
{
@@ -192,8 +257,11 @@ static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
struct eventfd_ctx *trigger;
int ret;

+
if (irq->trigger) {
free_irq(irq->hwirq, irq);
+ irq_bypass_unregister_producer(irq->prod);
+ kfree(irq->prod);
kfree(irq->name);
eventfd_ctx_put(irq->trigger);
irq->trigger = NULL;
@@ -225,6 +293,21 @@ static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
return ret;
}

+ irq->prod = kzalloc(sizeof(struct irq_bypass_producer),
+ GFP_KERNEL);
+ if (!irq->prod)
+ return -ENOMEM;
+ irq->prod->token = (void *)trigger;
+ irq->prod->irq = irq->hwirq;
+ irq->prod->vdev = vfio_device_get_from_dev(vdev->dev);
+ irq->prod->opaque = (void *)vdev;
+ irq->prod->add_consumer = vfio_platform_add_consumer;
+ irq->prod->del_consumer = vfio_platform_del_consumer;
+ irq->prod->stop_producer = vfio_platform_stop_producer;
+ irq->prod->resume_producer = vfio_platform_resume_producer;
+ ret = irq_bypass_register_producer(irq->prod);
+ WARN_ON(ret);
+
if (!irq->masked)
enable_irq(irq->hwirq);

diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index 5f46c68..1255306 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -38,6 +38,7 @@ struct vfio_platform_irq {
struct virqfd *unmask;
struct virqfd *mask;
irqreturn_t (*handler)(int irq, void *dev_id);
+ struct irq_bypass_producer *prod;
};

struct vfio_platform_region {
@@ -57,6 +58,7 @@ struct vfio_platform_device {
u32 num_irqs;
int refcnt;
struct mutex igate;
+ struct device *dev;

/*
* These fields should be filled by the bus specific binder
--
1.9.1