Re: [PATCH v7 09/20] KVM: selftests: Add VFIO device support to eventfd IRQ test

[Sean Christopherson <seanjc@google.com>]

On Thu, Jun 18, 2026, David Matlack wrote:
> On 2026-06-12 05:20 PM, Sean Christopherson wrote:
> > From: David Matlack <dmatlack@google.com>
> > 
> > Extend the eventfd IRQ test with a '-d' argument that takes a BDF (in the
> > format segment:bus:device.function) of an interrupt-capable PCI(e) device
> > bound to VFIO, and use said device to trigger interrupts instead of always
> > synthesizing interrupts via direct writes to the eventfd.
> > 
> > Using a VFIO device to trigger interrupts validates the end-to-end delivery
> > of IRQs for "real" devices, and when supported by hardware (and KVM), also
> > validates interrupt delivery via IRQ bypass, i.e. via device posted IRQs.
> > 
> > Now that IOMMUFD is a thing, auto-probe IOMMUFD vs. "legacy" VFIO by
> > temporarily opening /dev/iommufd, and skip the test if neither IOMMUFD nor
> > legacy VFIO is available.  Add a '-t' option to the user override the probe
> > logic, e.g. in case IOMMUFD is available but the system is configured for
> > legacy usage.
> > 
> > Note, the device must have a VFIO selftest driver in order to work with
> > the test.  A helper script to list supported devices will hopefully be
> > available in the near future at
> > tools/testing/selftests/vfio/scripts/list_supported_devices.sh[1].
> 
> > +static int vfio_setup_msi(struct vfio_pci_device *device)
> > +{
> > +	const int flags = MAP_SHARED | MAP_ANONYMOUS;
> > +	const int prot = PROT_READ | PROT_WRITE;
> > +	struct dma_region *region;
> > +
> > +	/* A driver is required to generate an MSI. */
> > +	TEST_REQUIRE(device->driver.ops);
> 
> This series is probably going to race with merging another VFIO
> selftests patch to make send_msi() optional [1]. Can you add a check for
> that here?
> 
>   TEST_REQUIRE(device->driver.ops);
>   TEST_REQUIRE(device->driver.ops->send_msi);

Ya, will do.