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path: root/drivers/vfio/pci/vfio_pci_intrs.c
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Diffstat (limited to 'drivers/vfio/pci/vfio_pci_intrs.c')
-rw-r--r--drivers/vfio/pci/vfio_pci_intrs.c176
1 files changed, 106 insertions, 70 deletions
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index 237beac83809..fb5392b749ff 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -90,22 +90,28 @@ static void vfio_send_intx_eventfd(void *opaque, void *unused)
if (likely(is_intx(vdev) && !vdev->virq_disabled)) {
struct vfio_pci_irq_ctx *ctx;
+ struct eventfd_ctx *trigger;
ctx = vfio_irq_ctx_get(vdev, 0);
if (WARN_ON_ONCE(!ctx))
return;
- eventfd_signal(ctx->trigger);
+
+ trigger = READ_ONCE(ctx->trigger);
+ if (likely(trigger))
+ eventfd_signal(trigger);
}
}
/* Returns true if the INTx vfio_pci_irq_ctx.masked value is changed. */
-bool vfio_pci_intx_mask(struct vfio_pci_core_device *vdev)
+static bool __vfio_pci_intx_mask(struct vfio_pci_core_device *vdev)
{
struct pci_dev *pdev = vdev->pdev;
struct vfio_pci_irq_ctx *ctx;
unsigned long flags;
bool masked_changed = false;
+ lockdep_assert_held(&vdev->igate);
+
spin_lock_irqsave(&vdev->irqlock, flags);
/*
@@ -143,6 +149,17 @@ out_unlock:
return masked_changed;
}
+bool vfio_pci_intx_mask(struct vfio_pci_core_device *vdev)
+{
+ bool mask_changed;
+
+ mutex_lock(&vdev->igate);
+ mask_changed = __vfio_pci_intx_mask(vdev);
+ mutex_unlock(&vdev->igate);
+
+ return mask_changed;
+}
+
/*
* If this is triggered by an eventfd, we can't call eventfd_signal
* or else we'll deadlock on the eventfd wait queue. Return >0 when
@@ -194,12 +211,21 @@ out_unlock:
return ret;
}
-void vfio_pci_intx_unmask(struct vfio_pci_core_device *vdev)
+static void __vfio_pci_intx_unmask(struct vfio_pci_core_device *vdev)
{
+ lockdep_assert_held(&vdev->igate);
+
if (vfio_pci_intx_unmask_handler(vdev, NULL) > 0)
vfio_send_intx_eventfd(vdev, NULL);
}
+void vfio_pci_intx_unmask(struct vfio_pci_core_device *vdev)
+{
+ mutex_lock(&vdev->igate);
+ __vfio_pci_intx_unmask(vdev);
+ mutex_unlock(&vdev->igate);
+}
+
static irqreturn_t vfio_intx_handler(int irq, void *dev_id)
{
struct vfio_pci_core_device *vdev = dev_id;
@@ -231,97 +257,100 @@ static irqreturn_t vfio_intx_handler(int irq, void *dev_id)
return ret;
}
-static int vfio_intx_enable(struct vfio_pci_core_device *vdev)
+static int vfio_intx_enable(struct vfio_pci_core_device *vdev,
+ struct eventfd_ctx *trigger)
{
+ struct pci_dev *pdev = vdev->pdev;
struct vfio_pci_irq_ctx *ctx;
+ unsigned long irqflags;
+ char *name;
+ int ret;
if (!is_irq_none(vdev))
return -EINVAL;
- if (!vdev->pdev->irq)
+ if (!pdev->irq)
return -ENODEV;
+ name = kasprintf(GFP_KERNEL_ACCOUNT, "vfio-intx(%s)", pci_name(pdev));
+ if (!name)
+ return -ENOMEM;
+
ctx = vfio_irq_ctx_alloc(vdev, 0);
if (!ctx)
return -ENOMEM;
+ ctx->name = name;
+ ctx->trigger = trigger;
+
/*
- * If the virtual interrupt is masked, restore it. Devices
- * supporting DisINTx can be masked at the hardware level
- * here, non-PCI-2.3 devices will have to wait until the
- * interrupt is enabled.
+ * Fill the initial masked state based on virq_disabled. After
+ * enable, changing the DisINTx bit in vconfig directly changes INTx
+ * masking. igate prevents races during setup, once running masked
+ * is protected via irqlock.
+ *
+ * Devices supporting DisINTx also reflect the current mask state in
+ * the physical DisINTx bit, which is not affected during IRQ setup.
+ *
+ * Devices without DisINTx support require an exclusive interrupt.
+ * IRQ masking is performed at the IRQ chip. Again, igate protects
+ * against races during setup and IRQ handlers and irqfds are not
+ * yet active, therefore masked is stable and can be used to
+ * conditionally auto-enable the IRQ.
+ *
+ * irq_type must be stable while the IRQ handler is registered,
+ * therefore it must be set before request_irq().
*/
ctx->masked = vdev->virq_disabled;
- if (vdev->pci_2_3)
- pci_intx(vdev->pdev, !ctx->masked);
+ if (vdev->pci_2_3) {
+ pci_intx(pdev, !ctx->masked);
+ irqflags = IRQF_SHARED;
+ } else {
+ irqflags = ctx->masked ? IRQF_NO_AUTOEN : 0;
+ }
vdev->irq_type = VFIO_PCI_INTX_IRQ_INDEX;
+ ret = request_irq(pdev->irq, vfio_intx_handler,
+ irqflags, ctx->name, vdev);
+ if (ret) {
+ vdev->irq_type = VFIO_PCI_NUM_IRQS;
+ kfree(name);
+ vfio_irq_ctx_free(vdev, ctx, 0);
+ return ret;
+ }
+
return 0;
}
-static int vfio_intx_set_signal(struct vfio_pci_core_device *vdev, int fd)
+static int vfio_intx_set_signal(struct vfio_pci_core_device *vdev,
+ struct eventfd_ctx *trigger)
{
struct pci_dev *pdev = vdev->pdev;
- unsigned long irqflags = IRQF_SHARED;
struct vfio_pci_irq_ctx *ctx;
- struct eventfd_ctx *trigger;
- unsigned long flags;
- int ret;
+ struct eventfd_ctx *old;
ctx = vfio_irq_ctx_get(vdev, 0);
if (WARN_ON_ONCE(!ctx))
return -EINVAL;
- if (ctx->trigger) {
- free_irq(pdev->irq, vdev);
- kfree(ctx->name);
- eventfd_ctx_put(ctx->trigger);
- ctx->trigger = NULL;
- }
-
- if (fd < 0) /* Disable only */
- return 0;
+ old = ctx->trigger;
- ctx->name = kasprintf(GFP_KERNEL_ACCOUNT, "vfio-intx(%s)",
- pci_name(pdev));
- if (!ctx->name)
- return -ENOMEM;
+ WRITE_ONCE(ctx->trigger, trigger);
- trigger = eventfd_ctx_fdget(fd);
- if (IS_ERR(trigger)) {
- kfree(ctx->name);
- return PTR_ERR(trigger);
+ /* Releasing an old ctx requires synchronizing in-flight users */
+ if (old) {
+ synchronize_irq(pdev->irq);
+ vfio_virqfd_flush_thread(&ctx->unmask);
+ eventfd_ctx_put(old);
}
- ctx->trigger = trigger;
-
- if (!vdev->pci_2_3)
- irqflags = 0;
-
- ret = request_irq(pdev->irq, vfio_intx_handler,
- irqflags, ctx->name, vdev);
- if (ret) {
- ctx->trigger = NULL;
- kfree(ctx->name);
- eventfd_ctx_put(trigger);
- return ret;
- }
-
- /*
- * INTx disable will stick across the new irq setup,
- * disable_irq won't.
- */
- spin_lock_irqsave(&vdev->irqlock, flags);
- if (!vdev->pci_2_3 && ctx->masked)
- disable_irq_nosync(pdev->irq);
- spin_unlock_irqrestore(&vdev->irqlock, flags);
-
return 0;
}
static void vfio_intx_disable(struct vfio_pci_core_device *vdev)
{
+ struct pci_dev *pdev = vdev->pdev;
struct vfio_pci_irq_ctx *ctx;
ctx = vfio_irq_ctx_get(vdev, 0);
@@ -329,10 +358,13 @@ static void vfio_intx_disable(struct vfio_pci_core_device *vdev)
if (ctx) {
vfio_virqfd_disable(&ctx->unmask);
vfio_virqfd_disable(&ctx->mask);
+ free_irq(pdev->irq, vdev);
+ if (ctx->trigger)
+ eventfd_ctx_put(ctx->trigger);
+ kfree(ctx->name);
+ vfio_irq_ctx_free(vdev, ctx, 0);
}
- vfio_intx_set_signal(vdev, -1);
vdev->irq_type = VFIO_PCI_NUM_IRQS;
- vfio_irq_ctx_free(vdev, ctx, 0);
}
/*
@@ -560,11 +592,11 @@ static int vfio_pci_set_intx_unmask(struct vfio_pci_core_device *vdev,
return -EINVAL;
if (flags & VFIO_IRQ_SET_DATA_NONE) {
- vfio_pci_intx_unmask(vdev);
+ __vfio_pci_intx_unmask(vdev);
} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
uint8_t unmask = *(uint8_t *)data;
if (unmask)
- vfio_pci_intx_unmask(vdev);
+ __vfio_pci_intx_unmask(vdev);
} else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
struct vfio_pci_irq_ctx *ctx = vfio_irq_ctx_get(vdev, 0);
int32_t fd = *(int32_t *)data;
@@ -591,11 +623,11 @@ static int vfio_pci_set_intx_mask(struct vfio_pci_core_device *vdev,
return -EINVAL;
if (flags & VFIO_IRQ_SET_DATA_NONE) {
- vfio_pci_intx_mask(vdev);
+ __vfio_pci_intx_mask(vdev);
} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
uint8_t mask = *(uint8_t *)data;
if (mask)
- vfio_pci_intx_mask(vdev);
+ __vfio_pci_intx_mask(vdev);
} else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
return -ENOTTY; /* XXX implement me */
}
@@ -616,19 +648,23 @@ static int vfio_pci_set_intx_trigger(struct vfio_pci_core_device *vdev,
return -EINVAL;
if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
+ struct eventfd_ctx *trigger = NULL;
int32_t fd = *(int32_t *)data;
int ret;
- if (is_intx(vdev))
- return vfio_intx_set_signal(vdev, fd);
+ if (fd >= 0) {
+ trigger = eventfd_ctx_fdget(fd);
+ if (IS_ERR(trigger))
+ return PTR_ERR(trigger);
+ }
- ret = vfio_intx_enable(vdev);
- if (ret)
- return ret;
+ if (is_intx(vdev))
+ ret = vfio_intx_set_signal(vdev, trigger);
+ else
+ ret = vfio_intx_enable(vdev, trigger);
- ret = vfio_intx_set_signal(vdev, fd);
- if (ret)
- vfio_intx_disable(vdev);
+ if (ret && trigger)
+ eventfd_ctx_put(trigger);
return ret;
}
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-06-01 06:41:29 +0000