[PATCH v7 2/3] VFIO-AER: Vfio-pci driver changes for supporting AER

From: Vijay Mohan Pandarathil
Date: Sat Mar 09 2013 - 02:53:08 EST


- New VFIO_SET_IRQ ioctl option to pass the eventfd that is signaled when
an error occurs in the vfio_pci_device

- Register pci_error_handler for the vfio_pci driver

- When the device encounters an error, the error handler registered by
the vfio_pci driver gets invoked by the AER infrastructure

- In the error handler, signal the eventfd registered for the device.

- This results in the qemu eventfd handler getting invoked and
appropriate action taken for the guest.

Signed-off-by: Vijay Mohan Pandarathil <vijaymohan.pandarathil@xxxxxx>
---
drivers/vfio/pci/vfio_pci.c | 44 ++++++++++++++++++++++++-
drivers/vfio/pci/vfio_pci_intrs.c | 64 +++++++++++++++++++++++++++++++++++++
drivers/vfio/pci/vfio_pci_private.h | 1 +
include/uapi/linux/vfio.h | 1 +
4 files changed, 109 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 8189cb6..acfcb1a 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -201,7 +201,9 @@ static int vfio_pci_get_irq_count(struct vfio_pci_device *vdev, int irq_type)

return (flags & PCI_MSIX_FLAGS_QSIZE) + 1;
}
- }
+ } else if (irq_type == VFIO_PCI_ERR_IRQ_INDEX)
+ if (pci_is_pcie(vdev->pdev))
+ return 1;

return 0;
}
@@ -317,6 +319,17 @@ static long vfio_pci_ioctl(void *device_data,
if (info.argsz < minsz || info.index >= VFIO_PCI_NUM_IRQS)
return -EINVAL;

+ switch (info.index) {
+ case VFIO_PCI_INTX_IRQ_INDEX ... VFIO_PCI_MSIX_IRQ_INDEX:
+ break;
+ case VFIO_PCI_ERR_IRQ_INDEX:
+ if (pci_is_pcie(vdev->pdev))
+ break;
+ /* pass thru to return error */
+ default:
+ return -EINVAL;
+ }
+
info.flags = VFIO_IRQ_INFO_EVENTFD;

info.count = vfio_pci_get_irq_count(vdev, info.index);
@@ -551,11 +564,40 @@ static void vfio_pci_remove(struct pci_dev *pdev)
kfree(vdev);
}

+static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
+ pci_channel_state_t state)
+{
+ struct vfio_pci_device *vdev;
+ struct vfio_device *device;
+
+ device = vfio_device_get_from_dev(&pdev->dev);
+ if (device == NULL)
+ return PCI_ERS_RESULT_DISCONNECT;
+
+ vdev = vfio_device_data(device);
+ if (vdev == NULL) {
+ vfio_device_put(device);
+ return PCI_ERS_RESULT_DISCONNECT;
+ }
+
+ if (vdev->err_trigger)
+ eventfd_signal(vdev->err_trigger, 1);
+
+ vfio_device_put(device);
+
+ return PCI_ERS_RESULT_CAN_RECOVER;
+}
+
+static struct pci_error_handlers vfio_err_handlers = {
+ .error_detected = vfio_pci_aer_err_detected,
+};
+
static struct pci_driver vfio_pci_driver = {
.name = "vfio-pci",
.id_table = NULL, /* only dynamic ids */
.probe = vfio_pci_probe,
.remove = vfio_pci_remove,
+ .err_handler = &vfio_err_handlers,
};

static void __exit vfio_pci_cleanup(void)
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index 3639371..b84bf22 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -745,6 +745,63 @@ static int vfio_pci_set_msi_trigger(struct vfio_pci_device *vdev,
return 0;
}

+static int vfio_pci_set_err_trigger(struct vfio_pci_device *vdev,
+ unsigned index, unsigned start,
+ unsigned count, uint32_t flags, void *data)
+{
+ int32_t fd = *(int32_t *)data;
+ struct pci_dev *pdev = vdev->pdev;
+
+ if ((index != VFIO_PCI_ERR_IRQ_INDEX) ||
+ !(flags & VFIO_IRQ_SET_DATA_TYPE_MASK))
+ return -EINVAL;
+
+ /*
+ * device_lock synchronizes setting and checking of
+ * err_trigger. The vfio_pci_aer_err_detected() is also
+ * called with device_lock held.
+ */
+
+ /* DATA_NONE/DATA_BOOL enables loopback testing */
+
+ if (flags & VFIO_IRQ_SET_DATA_NONE) {
+ device_lock(&pdev->dev);
+ if (vdev->err_trigger)
+ eventfd_signal(vdev->err_trigger, 1);
+ device_unlock(&pdev->dev);
+ return 0;
+ } else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
+ uint8_t trigger = *(uint8_t *)data;
+ device_lock(&pdev->dev);
+ if (trigger && vdev->err_trigger)
+ eventfd_signal(vdev->err_trigger, 1);
+ device_unlock(&pdev->dev);
+ return 0;
+ }
+
+ /* Handle SET_DATA_EVENTFD */
+
+ if (fd == -1) {
+ device_lock(&pdev->dev);
+ if (vdev->err_trigger)
+ eventfd_ctx_put(vdev->err_trigger);
+ vdev->err_trigger = NULL;
+ device_unlock(&pdev->dev);
+ return 0;
+ } else if (fd >= 0) {
+ struct eventfd_ctx *efdctx;
+ efdctx = eventfd_ctx_fdget(fd);
+ if (IS_ERR(efdctx))
+ return PTR_ERR(efdctx);
+ device_lock(&pdev->dev);
+ if (vdev->err_trigger)
+ eventfd_ctx_put(vdev->err_trigger);
+ vdev->err_trigger = efdctx;
+ device_unlock(&pdev->dev);
+ return 0;
+ } else
+ return -EINVAL;
+}
int vfio_pci_set_irqs_ioctl(struct vfio_pci_device *vdev, uint32_t flags,
unsigned index, unsigned start, unsigned count,
void *data)
@@ -779,6 +836,13 @@ int vfio_pci_set_irqs_ioctl(struct vfio_pci_device *vdev, uint32_t flags,
break;
}
break;
+ case VFIO_PCI_ERR_IRQ_INDEX:
+ switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
+ case VFIO_IRQ_SET_ACTION_TRIGGER:
+ if (pci_is_pcie(vdev->pdev))
+ func = vfio_pci_set_err_trigger;
+ break;
+ }
}

if (!func)
diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
index d7e55d0..9c6d5d0 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -56,6 +56,7 @@ struct vfio_pci_device {
bool has_vga;
struct pci_saved_state *pci_saved_state;
atomic_t refcnt;
+ struct eventfd_ctx *err_trigger;
};

#define is_intx(vdev) (vdev->irq_type == VFIO_PCI_INTX_IRQ_INDEX)
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 4f41f30..284ff24 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -319,6 +319,7 @@ enum {
VFIO_PCI_INTX_IRQ_INDEX,
VFIO_PCI_MSI_IRQ_INDEX,
VFIO_PCI_MSIX_IRQ_INDEX,
+ VFIO_PCI_ERR_IRQ_INDEX,
VFIO_PCI_NUM_IRQS
};

--
1.7.11.3

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