From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
To: jeremy@goop.org
Cc: fujita.tomonori@lab.ntt.co.jp, galak@kernel.crashing.org,
hch@infradead.org, linux-kernel@vger.kernel.org, mingo@elte.hu,
ian.campbell@citrix.com, beckyb@kernel.crashing.org
Subject: Re: [PATCH 4/7] swiotlb: Allow arch override of address_needs_mapping
Date: Thu, 9 Apr 2009 07:10:32 +0900 [thread overview]
Message-ID: <20090409071032M.fujita.tomonori@lab.ntt.co.jp> (raw)
In-Reply-To: <49DD1D6B.6030001@goop.org>
On Wed, 08 Apr 2009 14:55:55 -0700
Jeremy Fitzhardinge <jeremy@goop.org> wrote:
> FUJITA Tomonori wrote:
> > On Wed, 8 Apr 2009 15:56:32 -0500
> > Kumar Gala <galak@kernel.crashing.org> wrote:
> >
> >
> >> On Apr 8, 2009, at 3:38 PM, Christoph Hellwig wrote:
> >>
> >>
> >>> On Wed, Apr 08, 2009 at 09:09:18AM -0500, Kumar Gala wrote:
> >>>
> >>>> From: Becky Bruce <beckyb@kernel.crashing.org>
> >>>>
> >>>> Some architectures require additional checking to determine
> >>>> if a device can dma to an address and need to provide their
> >>>> own address_needs_mapping..
> >>>>
> >>> Shouldn't we just move it completely to the arch? I think that ia64
> >>> and
> >>> x86 currently use the same one is more of an accident.
> >>>
> >> It seems like the swiotlb code uses __weak for a number of things:
> >>
> >> lib/swiotlb.c:void * __weak __init swiotlb_alloc_boot(size_t size,
> >> unsigned long nslabs)
> >> lib/swiotlb.c:void * __weak swiotlb_alloc(unsigned order, unsigned
> >> long nslabs)
> >> lib/swiotlb.c:dma_addr_t __weak swiotlb_phys_to_bus(struct device
> >> *hwdev, phys_addr_t paddr)
> >> lib/swiotlb.c:phys_addr_t __weak swiotlb_bus_to_phys(struct device
> >> *hwdev, dma_addr_t baddr)
> >> lib/swiotlb.c:void * __weak swiotlb_bus_to_virt(struct device *hwdev,
> >> dma_addr_t address)
> >> lib/swiotlb.c:int __weak swiotlb_arch_address_needs_mapping(struct
> >> device *hwdev,
> >> lib/swiotlb.c:int __weak swiotlb_arch_range_needs_mapping(phys_addr_t
> >> paddr, size_t size)
> >>
> >> instead of #ifndef HAVE_ARCH_<FOO>. Not sure if there is a historical
> >> reason for that.
> >>
> >
> > ia64 and x86_64 use swiotlb but neither need this function. And
> > neither need any above __weak. They were added for dom0 support.
> > Yeah, swiotlb is much cleaner and better if we don't add dom0 support.
> >
>
> Some architectures need non-trivial bus<->phys conversion routines, etc,
Only Xen needs such conversion for swiotlb.
> so either we can require it that all architectures wishing to use
> swiotlb define these functions, or have weak default functions that can
> be overridden by architectures where necessary.
Can you give an example? I don't think IA64, X86_64 or POWER (which
will use swiotlb) need any __weak functions. If you say other archs
could use swiotlb, please tell me how they need these __weak.
> This isn't a specific Xen dom0 requirement, except that enabling it in
Yes, it is.
> the config will override these functions (but now in a Xen-only file,
> rather than affecting the normal x86 pci-swiotlb.c).
And again, x86' pci-swiotlb is much cleaner without dom0 support.
next prev parent reply other threads:[~2009-04-08 22:11 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-08 14:09 [PATCH V3 0/7] swiotlb: changes for powerpc/highmem Kumar Gala
2009-04-08 14:09 ` [PATCH 1/7] swiotlb: comment corrections (no code changes) Kumar Gala
2009-04-08 14:09 ` [PATCH 2/7] swiotlb: fix compile warning Kumar Gala
2009-04-08 14:09 ` [PATCH 3/7] swiotlb: map_page fix for highmem systems Kumar Gala
2009-04-08 14:09 ` [PATCH 4/7] swiotlb: Allow arch override of address_needs_mapping Kumar Gala
2009-04-08 14:09 ` [PATCH 5/7] swiotlb: Rename unmap_single to do_unmap_single Kumar Gala
2009-04-08 14:09 ` [PATCH 6/7] swiotlb: Use swiotlb_sync_single instead of duplicating code Kumar Gala
2009-04-08 14:09 ` [PATCH 7/7] swiotlb: Change swiotlb_bus_to[phys,virt] prototypes Kumar Gala
2009-04-08 15:25 ` [tip:core/iommu] swiotlb: change " Becky Bruce
2009-04-08 15:25 ` [tip:core/iommu] swiotlb: use swiotlb_sync_single instead of duplicating code Becky Bruce
2009-04-08 15:25 ` [tip:core/iommu] swiotlb: rename unmap_single to do_unmap_single Becky Bruce
2009-04-08 15:25 ` [tip:core/iommu] swiotlb: allow arch override of address_needs_mapping Becky Bruce
2009-04-08 20:38 ` [PATCH 4/7] swiotlb: Allow " Christoph Hellwig
2009-04-08 20:56 ` Kumar Gala
2009-04-08 21:15 ` FUJITA Tomonori
2009-04-08 21:55 ` Jeremy Fitzhardinge
2009-04-08 22:10 ` FUJITA Tomonori [this message]
2009-04-08 22:36 ` Jeremy Fitzhardinge
2009-04-08 23:01 ` FUJITA Tomonori
2009-04-08 23:16 ` Jeremy Fitzhardinge
2009-04-08 23:37 ` FUJITA Tomonori
2009-04-09 0:09 ` Jeremy Fitzhardinge
2009-04-09 4:43 ` Kumar Gala
2009-04-09 18:34 ` FUJITA Tomonori
2009-04-09 19:19 ` Jeremy Fitzhardinge
2009-04-09 19:43 ` FUJITA Tomonori
2009-04-09 19:50 ` FUJITA Tomonori
2009-04-09 19:54 ` Jeremy Fitzhardinge
2009-04-09 4:59 ` Kumar Gala
2009-04-09 18:50 ` FUJITA Tomonori
2009-04-09 20:10 ` Kumar Gala
2009-04-09 20:25 ` Kumar Gala
2009-04-08 22:24 ` Christoph Hellwig
2009-04-08 15:24 ` [tip:core/iommu] swiotlb: map_page fix for highmem systems Becky Bruce
2009-04-08 15:24 ` [tip:core/iommu] swiotlb: fix compile warning Becky Bruce
2009-04-08 15:24 ` [tip:core/iommu] swiotlb: comment corrections Becky Bruce
2009-04-08 14:21 ` [PATCH V3 0/7] swiotlb: changes for powerpc/highmem Ingo Molnar
-- strict thread matches above, loose matches on Subject: below --
2009-04-04 1:56 [PATCH V2 " Becky Bruce
2009-04-04 1:56 ` [PATCH 1/7] swiotlb: comment corrections (no code changes) Becky Bruce
2009-04-04 1:56 ` [PATCH 2/7] swiotlb: fix compile warning Becky Bruce
2009-04-04 1:56 ` [PATCH 3/7] swiotlb: map_page fix for highmem systems Becky Bruce
2009-04-04 1:56 ` [PATCH 4/7] swiotlb: Allow arch override of address_needs_mapping Becky Bruce
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