Re: [PATCH 8/8 v4] PCI: document the changes

From: Pavel Machek
Date: Fri Oct 17 2008 - 19:04:44 EST


> Create how-to for SR-IOV user and device driver developer.
> Signed-off-by: Yu Zhao <yu.zhao@xxxxxxxxx>

> +1.1 What is SR-IOV
> +
> +Single Root I/O Virtualization (SR-IOV) is a PCI Express Extended
> +capability which makes one physical device appear as multiple virtual
> +devices. The physical device is referred to as Physical Function while
> +the virtual devices are referred to as Virtual Functions. Allocation
> +of Virtual Functions can be dynamically controlled by Physical Function
> +via registers encapsulated in the capability. By default, this feature
> +is not enabled and the Physical Function behaves as traditional PCIe
> +device. Once it's turned on, each Virtual Function's PCI configuration
> +space can be accessed by its own Bus, Device and Function Number (Routing
> +ID). And each Virtual Function also has PCI Memory Space, which is
> used

Ok, why is this optional? If intel cares about virtualization, it
should enable this by default. I dont see why this should be

> +#ifdef CONFIG_PM
> +/*
> + * If Physical Function supports the power management, then the
> + * SR-IOV needs to be disabled before the adapter goes to sleep,
> + * because Virtual Functions will not work when the adapter is in
> + * the power-saving mode.
> + * The SR-IOV can be enabled again after the adapter wakes up.
> + */

How beatiful :-(.

(cesky, pictures)
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