On Wed, 20 Apr 2022 15:16:01 +0800
Hogan Wang <hogan.wang@xxxxxxxxxx> wrote:
> As you all know, device faults are classified into the following
> types: unrecoverable error and recoverable error. vfio-pci drvier
> will report error event to user-space process while device occur
> hardware errors, and still report the other error event after deivce
> recovery successful. So the user-space process just like qemu can not
> identify the event is an hardware error event or a device recovery
> successful event. So in order to solve this problem, add an eventfd
> named recov_trigger to report device recovery successful event, the
> user-space process can make a decision whether to process the recovery
> event or not.
>
> Signed-off-by: Hogan Wang <hogan.wang@xxxxxxxxxx>
> ---
> drivers/vfio/pci/vfio_pci_core.c | 13 +++++++++++--
> drivers/vfio/pci/vfio_pci_intrs.c | 19 +++++++++++++++++++
> include/linux/vfio_pci_core.h | 1 +
> include/uapi/linux/vfio.h | 1 +
> 4 files changed, 32 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index b7bb16f92ac6..2360cb44aa36 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -483,6 +483,10 @@ void vfio_pci_core_close_device(struct vfio_device *core_vdev)
> eventfd_ctx_put(vdev->err_trigger);
> vdev->err_trigger = NULL;
> }
> + if (vdev->recov_trigger) {
> + eventfd_ctx_put(vdev->recov_trigger);
> + vdev->recov_trigger = NULL;
> + }
> if (vdev->req_trigger) {
> eventfd_ctx_put(vdev->req_trigger);
> vdev->req_trigger = NULL;
> @@ -1922,8 +1926,13 @@ pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev,
>
> mutex_lock(&vdev->igate);
>
> - if (vdev->err_trigger)
> - eventfd_signal(vdev->err_trigger, 1);
> + if (state == pci_channel_io_normal) {
> + if (vdev->recov_trigger)
> + eventfd_signal(vdev->recov_trigger, 1);
> + } else {
> + if (vdev->err_trigger)
> + eventfd_signal(vdev->err_trigger, 1);
> + }
The goal of the existing notification is to signal on any uncorrected
error which requires intervention at the device. Here we're masking
non-fatal, ie. recoverable, errors from that existing mechanism. There
is no userspace that currently handles this new recovery notification,
therefore this is not a backwards compatible proposal.
I also don't see how an asynchronous notification to userspace allows
the device to continue operating, the problem is not as simple as
raising a different interrupt. Thanks,
Alex
>
> mutex_unlock(&vdev->igate);
>
> diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
> index 6069a11fb51a..be76ff76c361 100644
> --- a/drivers/vfio/pci/vfio_pci_intrs.c
> +++ b/drivers/vfio/pci/vfio_pci_intrs.c
> @@ -624,6 +624,17 @@ static int vfio_pci_set_err_trigger(struct vfio_pci_core_device *vdev,
> count, flags, data);
> }
>
> +static int vfio_pci_set_recov_trigger(struct vfio_pci_core_device *vdev,
> + unsigned index, unsigned start,
> + unsigned count, uint32_t flags, void *data)
> +{
> + if (index != VFIO_PCI_ERR_IRQ_INDEX || start != 0 || count > 1)
> + return -EINVAL;
> +
> + return vfio_pci_set_ctx_trigger_single(&vdev->recov_trigger,
> + count, flags, data);
> +}
> +
> static int vfio_pci_set_req_trigger(struct vfio_pci_core_device *vdev,
> unsigned index, unsigned start,
> unsigned count, uint32_t flags, void *data)
> @@ -684,6 +695,14 @@ int vfio_pci_set_irqs_ioctl(struct vfio_pci_core_device *vdev, uint32_t flags,
> break;
> }
> break;
> + case VFIO_PCI_RECOV_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_recov_trigger;
> + break;
> + }
> + break;
> }
>
> if (!func)
> diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
> index 74a4a0f17b28..d94addb18118 100644
> --- a/include/linux/vfio_pci_core.h
> +++ b/include/linux/vfio_pci_core.h
> @@ -128,6 +128,7 @@ struct vfio_pci_core_device {
> struct pci_saved_state *pm_save;
> int ioeventfds_nr;
> struct eventfd_ctx *err_trigger;
> + struct eventfd_ctx *recov_trigger;
> struct eventfd_ctx *req_trigger;
> struct list_head dummy_resources_list;
> struct mutex ioeventfds_lock;
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index fea86061b44e..f88a6ca62c49 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -621,6 +621,7 @@ enum {
> VFIO_PCI_MSIX_IRQ_INDEX,
> VFIO_PCI_ERR_IRQ_INDEX,
> VFIO_PCI_REQ_IRQ_INDEX,
> + VFIO_PCI_RECOV_IRQ_INDEX,
> VFIO_PCI_NUM_IRQS
> };
>
