Re: [Xen-devel] Userspace PIO access under xen

["Michael S. Tsirkin" <mst@xxxxxxxxxxxxxx>]

Quoting r. Ian Pratt <m+Ian.Pratt@xxxxxxxxxxxx>:
> Subject: RE: [Xen-devel] Userspace PIO access under xen
> 
>  
> > > You have to use io_remap_pfn_range for mapping IO space. Using 
> > > remap_pfn_range is technically a bug in the i386 code.
> > 
> > #define io_remap_page_range(vma, vaddr, paddr, size, prot) \
> >                 remap_pfn_range(vma, vaddr, (paddr) >> 
> > PAGE_SHIFT, size, prot)
> > 
> > So I just tested again and of course io_remap_pfn_range gives 
> > the same result.
> > 
> > > I believe the pfn_range functions are preferred over page_range 
> > > functions anyhow.
> > 
> > I actually use remap_pfn_range, I mistyped that.
> 
> Look at arch/xen/kernel/devmem.c and include/asm-xen/asm-i386/pgtable.h
> 
> #define io_remap_page_range(vma,from,phys,size,prot) \
> direct_remap_area_pages(vma->vm_mm,from,phys,size,prot,DOMID_IO)
> 
> It works fine for /dev/mem. It's possible there's a definition missing
> for io_remap_pfn_range.
> 
> Ian
> 

Hmm.

I have

/lib/modules/2.6.12-xen0/source/include/asm-xen/asm-i386/pgtable.h ->
../../../../linux-2.6-xen-sparse/./include/asm-xen/asm-i386/./pgtable.h

But

# ls -l /lib/modules/2.6.12-xen0/source/include/asm/pgtable.h
 -rw-r--r--  4 root root 14618 Jun 17 22:48
 /lib/modules/2.6.12-xen0/source/include/asm/pgtable.h

so it seems that the install script didnt link asm/pgtable.h in place
correctly?

-- 
MST

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