https://bugs.dpdk.org/show_bug.cgi?id=361
Bug ID: 361
Summary: device reset handling with igb_uio
Product: DPDK
Version: unspecified
Hardware: All
OS: All
Status: UNCONFIRMED
Severity: normal
Priority: Normal
Component: ethdev
Assignee: dev@dpdk.org
Reporter: santosh.rasta...@broadcom.com
Target Milestone: ---
Created attachment 73
--> https://bugs.dpdk.org/attachment.cgi?id=73&action=edit
msi-x vector allocation for igb_uio after device reset
Hi,
I have a question on igb_uio.
>From the below function call traces, vfio-pci module frees/allocates msi-x
vector table as part of
interrupt disable/enable. Where as igb-uio module, only masks/unmasks the
msi-x interrupt.
Does this mean, when using igb_uio, device can't undergo reset which clears
MSI-X vector table?
How to handle device reset with igb_uio?
igb-uio:
rte_intr_disable->uio_intr_disable->igbuio_pci_irqcontrol->pci_msi_mask_irq
rte_intr_enable->uio_intr_enable->igbuio_pci_irqcontrol->pci_msi_unmask_irq
igbuio_pci_open->igbuio_pci_enable_interrupts->pci_alloc_irq_vectors/request_irq
igbuio_pci_release->igbuio_pci_disable_interrupts->free_irq->pci_free_irq_vectors
vfio-pci:
rte_intr_disable->vfio_disable_msix->vfio_pci_ioctl->vfio_msi_disable->pci_free_irq_vectors
rte_intr_enable->vfio_enable_msix->vfio_pci_ioctl->vfio_msi_enable->pci_alloc_irq_vectors/vfio_msi_set_vector_signal->request_irq
I am using the attached hack to overcome this. What is the correct way to
handle this?
This is a hack as I am assigning "udev->info.irq = -1" when interrupt is
disabled to prevent uio_write from exiting.
kernel/linux/igb_uio/igb_uio.c: igbuio_pci_irqcontrol
igbuio_pci_disable_interrupts(udev);
udev->info.irq = -1; <-- Assigning to -1 and not 0.
Basically uio_write will not call igbuio_pci_enable_interrupts to enable the
interrupts back if irq is 0.
drivers/uio/uio.c: uio_write
if (!idev->info->irq) {
retval = -EIO;
goto out;
}
if (!idev->info->irqcontrol) {
retval = -ENOSYS;
goto out;
}
retval = idev->info->irqcontrol(idev->info, irq_on);
Regards
-Santosh
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