[dpdk-dev] [PATCH] igb_uio: fix vmware e1000 input/output error

[Stephen Hemminger]

On Mon, 21 Mar 2016 11:07:56 +0100
Thomas Monjalon <thomas.monjalon at 6wind.com> wrote:

> 2016-03-21 17:01, Qian Xu:
> > INTX is badly emulated in Vmware, INTX toggle check didn't work
> > with Vmware e1000 device. The patch is to fix the issue.
> 
> Is it possible to detect a VMware e1000 device?
> 
> > --- a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
> > +++ b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
> >  	case RTE_INTR_MODE_LEGACY:
> > -		if (pci_intx_mask_supported(dev)) {
> > -			dev_dbg(&dev->dev, "using INTX");
> > -			udev->info.irq_flags = IRQF_SHARED;
> > -			udev->info.irq = dev->irq;
> > -			udev->mode = RTE_INTR_MODE_LEGACY;
> > -			break;
> > -		}
> > -		dev_notice(&dev->dev, "PCI INTX mask not supported\n");
> > +                dev_dbg(&dev->dev, "using INTX");
> > +                udev->info.irq_flags = IRQF_SHARED;
> > +                udev->info.irq = dev->irq;
> > +                udev->mode = RTE_INTR_MODE_LEGACY;
> > +                break;
> >  		/* fall back to no IRQ */
> >  	case RTE_INTR_MODE_NONE:
> 
> This patch is removing the INTX support detection and the
> fallback to no IRQ.
> 

I agree with Thomas. If the kernel's "does INTx work" test fails then
most likely VMware is broken and later attempts to mask the interrupt
won't work. Better to have the DPDK abstraction layer
handle this. The EAL should:
 1) log a message when detected
 2) report that link state (and data) interrupts are not supported
    by setting proper flags so application knows that LSC is not available.
 3) give an error return on all attempts to enable interrupts.