RE: [Xen-devel] IOMMU support: __direct_remap_pfn_range() fails

To:	"Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
Subject:	RE: [Xen-devel] IOMMU support: __direct_remap_pfn_range() fails
From:	"Langsdorf, Mark" <mark.langsdorf@xxxxxxx>
Date:	Fri, 30 Sep 2005 16:49:46 -0500
Delivery-date:	Fri, 30 Sep 2005 21:47:37 +0000
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Thread-topic:	[Xen-devel] IOMMU support: __direct_remap_pfn_range() fails

> > I am working on getting IOMMU support for AMD64.
> > ...the agpgart code is still failing.
> > 
> > I have tracked the problem down to line 92 of ioremap.c, in
> > __direct_remap_pfn_range().
> > The failing instruction is a call to
> > HYPERVISOR_mmu_update().  
> 
> What are the arguments to direct_remap_pfn_range?

struct struct_mm *mm = 0x804c9540
unsigned long address = 80000
unsigned long mfn = 4280
unsigned long size = 80000
pgprot_t prot = 77
domid_t domid = 7ff1

The arguments the HYPERVISOR call are
        u = 43418
        v - u = 800
        domid = 7ff1

> With a verbose=y build of Xen what debug output do you get 
> from xen (on the serial line).

(XEN) (file=/usr/src/xen-unstable/xen-source/xen/include/asm/mm.h,
line=202) 
Error pfn 4280: rd=ffff8300001c7080, od=0000000000000000, caf=00000000,
taf=0000000000000006

If I'm reading asm/mm.h:get_page() right, it's failing because
the page->count_info is 0, but I don't know who set that value
or if that's meaningful.

-Mark Langsdorf
AMD, Inc.


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