Re: [PATCH V2] VFIO driver: Non-privileged user level PCI drivers

[Randy Dunlap <randy.dunlap@oracle.com>]

On Tue, 08 Jun 2010 14:21:52 -0700 Tom Lyon wrote:

> diff -uprN linux-2.6.34/Documentation/vfio.txt vfio-linux-2.6.34/Documentation/vfio.txt
> --- linux-2.6.34/Documentation/vfio.txt	1969-12-31 16:00:00.000000000 -0800
> +++ vfio-linux-2.6.34/Documentation/vfio.txt	2010-06-07 15:05:42.000000000 -0700
> @@ -0,0 +1,177 @@

...

> +Interrupts:
> +
> +Device interrupts are translated by the vfio driver into input events on event
> +notification file descriptors created by the eventfd system call. The user
> +program must create one or more event descriptors and pass them to the vfio
> +driver via ioctls to arrange for the interrupt mapping:
> +1.
> +	efd = eventfd(0, 0);
> +	ioctl(vfio_fd, VFIO_EVENTFD_IRQ, &efd);
> +		This provides an eventfd for traditional IRQ interrupts.
> +		IRQs will be disable after each interrupt until the driver

		             disabled

> +		re-enables them via the PCI COMMAND register.
> +2.
> +	efd = eventfd(0, 0);
> +	ioctl(vfio_fd, VFIO_EVENTFD_MSI, &efd);
> +		This connects MSI interrupts to an eventfd.
> +3.
> + 	int arg[N+1];
> +	arg[0] = N;
> +	arg[1..N] = eventfd(0, 0);
> +	ioctl(vfio_fd, VFIO_EVENTFDS_MSIX, arg);
> +		This connects N MSI-X interrupts with N eventfds.


---
~Randy
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