Re: [Xen-ia64-devel] [Patch 2/2] paravirtualize mmap hundlers of /proc/bus/pci

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

On Sat, Feb 17, 2007 at 09:47:53AM +0900, Akio Takebe wrote:
Content-Description: Mail message body
> paravirtualize mmap hundler of /proc/bus/pci
> 
> Signed-off-by: Akio Takebe <takebe_akio@xxxxxxxxxxxxxx>
> 
> Best Regards,
> 
> Akio Takebe

Hi Akio.
It seems reasonable to use X as short term solution.
However this is hacky work around of each device drivers.
Such a work around would be necessary for each device drivers which
implements mmap. It is impossible to paravirtualize all of them.

add_window(), which registers io region and memory region,
calls ioremap with ACPI_IO_RANGE regions, but it doesn't
with ACPI_MEMORY_RANGE regions.
If the ioremap hypercall is called with ACPI_MEMORY_RANGE regions,
all pci devices are free from such paravirtualization.
Especially we can get rid of /dev/mem and pci mmap
paravirtualization to use X.

Presumably we don't want to map pci bridge which may be large 
so that we need to detect it somehow in add_window().
-- 
yamahata

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