Re: [PATCH v3 2/3] VFIO-AER: Vfio-pci driver changes for supporting AER

From: Blue Swirl
Date: Sun Feb 03 2013 - 11:20:46 EST

On Sun, Feb 3, 2013 at 2:10 PM, Pandarathil, Vijaymohan R
<vijaymohan.pandarathil@xxxxxx> 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@xxxxxx>
> ---
> 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;

I don't know what is the policy in Linux kernel for this, but I'd add
a comment about fall through here.

> + 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;
> +
> + 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;
> +
> + 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);
> + 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
> };
>
> --
> 1.7.11.3
>
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