* is_xen_swiotlb_buffer() vs CONFIG_HIGHMEM
@ 2009-12-14 15:02 Jan Beulich
2009-12-15 18:34 ` Jeremy Fitzhardinge
0 siblings, 1 reply; 3+ messages in thread
From: Jan Beulich @ 2009-12-14 15:02 UTC (permalink / raw)
To: Jeremy Fitzhardinge; +Cc: xen-devel
Jeremy,
shouldn't is_xen_swiotlb_buffer() also check against e.g. highstart_pfn
to deal with wrap-around potentially leading to aliasing of
[xen_io_tlb_start,xen_io_tlb_end)?
Jan
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: is_xen_swiotlb_buffer() vs CONFIG_HIGHMEM
2009-12-14 15:02 is_xen_swiotlb_buffer() vs CONFIG_HIGHMEM Jan Beulich
@ 2009-12-15 18:34 ` Jeremy Fitzhardinge
2009-12-16 7:40 ` Jan Beulich
0 siblings, 1 reply; 3+ messages in thread
From: Jeremy Fitzhardinge @ 2009-12-15 18:34 UTC (permalink / raw)
To: Jan Beulich; +Cc: xen-devel, Konrad Rzeszutek Wilk
On 12/14/2009 07:02 AM, Jan Beulich wrote:
> shouldn't is_xen_swiotlb_buffer() also check against e.g. highstart_pfn
> to deal with wrap-around potentially leading to aliasing of
> [xen_io_tlb_start,xen_io_tlb_end)?
>
So what you're saying is that if the pfn is for a high page, then
"__va(pfn << PAGE_SHIFT);" is simply invalid. The resulting addr is
undefined, and may end up erroneously aliasing with the xen tlb buffer.
Do I understand your concern properly?
J
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: is_xen_swiotlb_buffer() vs CONFIG_HIGHMEM
2009-12-15 18:34 ` Jeremy Fitzhardinge
@ 2009-12-16 7:40 ` Jan Beulich
0 siblings, 0 replies; 3+ messages in thread
From: Jan Beulich @ 2009-12-16 7:40 UTC (permalink / raw)
To: Jeremy Fitzhardinge; +Cc: xen-devel, Konrad Rzeszutek Wilk
>>> Jeremy Fitzhardinge <jeremy@goop.org> 15.12.09 19:34 >>>
>On 12/14/2009 07:02 AM, Jan Beulich wrote:
>> shouldn't is_xen_swiotlb_buffer() also check against e.g. highstart_pfn
>> to deal with wrap-around potentially leading to aliasing of
>> [xen_io_tlb_start,xen_io_tlb_end)?
>>
>
>So what you're saying is that if the pfn is for a high page, then
>"__va(pfn << PAGE_SHIFT);" is simply invalid. The resulting addr is
>undefined, and may end up erroneously aliasing with the xen tlb buffer.
>
>Do I understand your concern properly?
Yes.
Jan
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2009-12-16 7:40 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2009-12-14 15:02 is_xen_swiotlb_buffer() vs CONFIG_HIGHMEM Jan Beulich
2009-12-15 18:34 ` Jeremy Fitzhardinge
2009-12-16 7:40 ` Jan Beulich
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