> -----Original Message----- > From: Antonios Motakis [mailto:a.motakis@xxxxxxxxxxxxxxxxxxxxxx] > Sent: Wednesday, October 02, 2013 6:22 AM > To: Yoder Stuart-B08248 > Cc: Alex Williamson; kvm-arm; Linux IOMMU; Linux Samsung SOC; KVM devel > mailing list; Alexander Graf; VirtualOpenSystems Technical Team > Subject: Re: [PATCH 3/7] Return info for device and its memory regions > and interrupts > > On Tue, Oct 1, 2013 at 9:32 PM, Yoder Stuart-B08248 > <B08248@xxxxxxxxxxxxx> wrote: > >> Antonios Motakis wrote > >> > Alex Williamson <alex.williamson@xxxxxxxxxx> wrote: > >> > I notice all the open firmware calls here and I'm curious, > >> > will all platform devices be making use of open firmware? > >> > I don't know if this is synonymous with device tree or not. > >> > Thanks, > >> > >> This VFIO driver will support only devices implemented > >> on the device tree. While there can be platform devices > >> outside the device tree, I don't think it makes sense > >> to support them from the same driver. This is why I > >> originally called the driver VFIO_DT, however I renamed > >> it to VFIO_PLATFORM after feedback from the first > >> RFC. However personally, I still think the VFIO_DT name > >> is more appropriate since we don't support all platform > >> devices, only those that use the device tree. > > > > But there is no 'device tree' bus. The bus type we're > > dealing with is a platform bus. > > > > vfio for platform devices should be independent of whether > > the device was discovered in a device tree or not. > > All you're doing is exposing mappable regions and IRQs > > to user space and it does not matter where the info originated. > > > > You should be using platform bus structs here not > > reparsing device tree nodes. The struct > > platform_device already has resource info in the > > struct: > > > > struct platform_device { > > const char *name; > > u32 id; > > struct device dev; > > u32 num_resources; > > struct resource *resource; > > }; > > > > Stuart > > > > I will look into this. However, can we rely to have access to all > device resources through platform abstractions, for every type of > platform device The only resources we care about in vfio are mappable regions and irqs. So, yes I think we can rely on access to those resources. > It seems to me that platform devices that are not > backed by a specific description mechanism (such as device tree) may > include a lot of hard coded values etc in their drivers. If the platform device struct does not have reg/irq resources described then we can't expose them to user space with vfio. Stuart -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
