[Xen-devel] PCI MMIO issue

["Stephen Donnelly" <sfdonnelly@xxxxxxxxx>]

I posted this to the xen-users list first, they suggested I ask here.

I understood that in a Driver Domain that has access to a (PCI) device,
'native' drivers can be used, but I am having some problems with memory
mapped IO from user space.

I have a PCI device that has a 64kB mmio range at PCI_BAR_0.
This address space contains the registers for the device. My Linux driver
provides a char device that allows read/write/seek, and mmap for this
space. In Linux you can use either read/write/seek to access the space,
or memory map it via mmap and access it directly.

When using the driver
in dom0 under Xen 3.0.4, the read/write/seek method works fine but the
mmap does not. None of the related functions return errors, but the
mmap does not appear to access the correct memory. Is there anything I
am missing?

The mmap is performed by a remap_pfn_range() by the driver, and mmap() in the user space code.

I am running Ubuntu 6.10 AMD64 Server and I built Xen 3.0.4
from source, including the 2.6.16.33-xen kernel. The driver is running
in dom0, no other domains are present.

Thanks,
Stephen.

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