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SubjectRe: [PATCH v3 2/3] VFIO-AER: Vfio-pci driver changes for supporting AER
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On Sun, 2013-02-03 at 14:10 +0000, Pandarathil, Vijaymohan R wrote:
> - 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@hp.com>
> ---
> drivers/vfio/pci/vfio_pci.c | 43 ++++++++++++++++++++++++++++++++++++-
> drivers/vfio/pci/vfio_pci_intrs.c | 30 ++++++++++++++++++++++++++
> drivers/vfio/pci/vfio_pci_private.h | 1 +
> include/uapi/linux/vfio.h | 1 +
> 4 files changed, 74 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> index b28e66c..818b1ed 100644
> --- a/drivers/vfio/pci/vfio_pci.c
> +++ b/drivers/vfio/pci/vfio_pci.c
> @@ -196,7 +196,9 @@ 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;
> }
> @@ -302,6 +304,16 @@ 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;
> + default:
> + return -EINVAL;
> + }
> +
> info.flags = VFIO_IRQ_INFO_EVENTFD;
>
> info.count = vfio_pci_get_irq_count(vdev, info.index);
> @@ -538,11 +550,40 @@ 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 *vpdev;
> + void *vdev;

Can't vdev still be a struct vfio_device*? We're not de-referencing it,
so I don't think you'll get a warning.

> +
> + vdev = vfio_device_get_from_dev(&pdev->dev);
> + if (vdev == NULL)
> + return PCI_ERS_RESULT_DISCONNECT;
> +
> + vpdev = vfio_device_data(vdev);
> + if (vpdev == NULL) {
> + vfio_device_put(vdev);
> + return PCI_ERS_RESULT_DISCONNECT;
> + }
> +
> + if (vpdev->err_trigger)
> + eventfd_signal(vpdev->err_trigger, 1);
> +
> + vfio_device_put(vdev);
> +
> + 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..83035b1 100644
> --- a/drivers/vfio/pci/vfio_pci_intrs.c
> +++ b/drivers/vfio/pci/vfio_pci_intrs.c
> @@ -745,6 +745,29 @@ 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;
> +
> + if ((index != VFIO_PCI_ERR_IRQ_INDEX) ||
> + !(flags & VFIO_IRQ_SET_DATA_EVENTFD))
> + return -EINVAL;

Again, why no support for DATA_NONE or DATA_BOOL to enable loopback
support?

> +
> + if (fd == -1) {
> + if (vdev->err_trigger)
> + eventfd_ctx_put(vdev->err_trigger);
> + vdev->err_trigger = NULL;
> + return 0;
> + } else if (fd >= 0) {
> + vdev->err_trigger = eventfd_ctx_fdget(fd);
> + if (IS_ERR(vdev->err_trigger))
> + return PTR_ERR(vdev->err_trigger);

There's a bug here that if the fdget fails we leave an ERR_PTR in
vdev->err_trigger which is non-NULL, so we'll use it to try to trigger
and attempt to 'put' it above. You probably want to think about
ordering or locking to avoid races between the set here and the use
above too. Thanks,

Alex

> + 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 +802,13 @@ 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 611827c..daee62f 100644
> --- a/drivers/vfio/pci/vfio_pci_private.h
> +++ b/drivers/vfio/pci/vfio_pci_private.h
> @@ -55,6 +55,7 @@ struct vfio_pci_device {
> bool bardirty;
> 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 4758d1b..7d50af4 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -310,6 +310,7 @@ 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
> };
>





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