Commit Graph

33 Commits

Author SHA1 Message Date
Stefano Stabellini
1b65c4e5a9 swiotlb-xen: use xen_alloc/free_coherent_pages
Use xen_alloc_coherent_pages and xen_free_coherent_pages to allocate or
free coherent pages.

We need to be careful handling the pointer returned by
xen_alloc_coherent_pages, because on ARM the pointer is not equal to
phys_to_virt(*dma_handle). In fact virt_to_phys only works for kernel
direct mapped RAM memory.
In ARM case the pointer could be an ioremap address, therefore passing
it to virt_to_phys would give you another physical address that doesn't
correspond to it.

Make xen_create_contiguous_region take a phys_addr_t as start parameter to
avoid the virt_to_phys calls which would be incorrect.

Changes in v6:
- remove extra spaces.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-10-10 13:41:10 +00:00
Stefano Stabellini
eb1ddc00b8 swiotlb-xen: introduce xen_swiotlb_set_dma_mask
Implement xen_swiotlb_set_dma_mask, use it for set_dma_mask on arm.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2013-10-09 16:56:33 +00:00
Stefano Stabellini
83862ccfc0 xen/arm,arm64: enable SWIOTLB_XEN
Xen on arm and arm64 needs SWIOTLB_XEN: when running on Xen we need to
program the hardware with mfns rather than pfns for dma addresses.
Remove SWIOTLB_XEN dependency on X86 and PCI and make XEN select
SWIOTLB_XEN on arm and arm64.

At the moment always rely on swiotlb-xen, but when Xen starts supporting
hardware IOMMUs we'll be able to avoid it conditionally on the presence
of an IOMMU on the platform.

Implement xen_create_contiguous_region on arm and arm64: for the moment
we assume that dom0 has been mapped 1:1 (physical addresses == machine
addresses) therefore we don't need to call XENMEM_exchange. Simply
return the physical address as dma address.

Initialize the xen-swiotlb from xen_early_init (before the native
dma_ops are initialized), set xen_dma_ops to &xen_swiotlb_dma_ops.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>


Changes in v8:
- assume dom0 is mapped 1:1, no need to call XENMEM_exchange.

Changes in v7:
- call __set_phys_to_machine_multi from xen_create_contiguous_region and
xen_destroy_contiguous_region to update the P2M;
- don't call XENMEM_unpin, it has been removed;
- call XENMEM_exchange instead of XENMEM_exchange_and_pin;
- set nr_exchanged to 0 before calling the hypercall.

Changes in v6:
- introduce and export xen_dma_ops;
- call xen_mm_init from as arch_initcall.

Changes in v4:
- remove redefinition of DMA_ERROR_CODE;
- update the code to use XENMEM_exchange_and_pin and XENMEM_unpin;
- add a note about hardware IOMMU in the commit message.

Changes in v3:
- code style changes;
- warn on XENMEM_put_dma_buf failures.
2013-10-10 13:40:44 +00:00
Stefano Stabellini
69908907b0 xen: make xen_create_contiguous_region return the dma address
Modify xen_create_contiguous_region to return the dma address of the
newly contiguous buffer.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>


Changes in v4:
- use virt_to_machine instead of virt_to_bus.
2013-10-09 16:56:32 +00:00
Stefano Stabellini
781575cd81 swiotlb-xen: replace dma_length with sg_dma_len() macro
swiotlb-xen has an implicit dependency on CONFIG_NEED_SG_DMA_LENGTH.
Remove it by replacing dma_length with sg_dma_len.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-08-09 11:29:00 -04:00
Joe Perches
283c0972d5 xen: Convert printks to pr_<level>
Convert printks to pr_<level> (excludes printk(KERN_DEBUG...)
to be more consistent throughout the xen subsystem.

Add pr_fmt with KBUILD_MODNAME or "xen:" KBUILD_MODNAME
Coalesce formats and add missing word spaces
Add missing newlines
Align arguments and reflow to 80 columns
Remove DRV_NAME from formats as pr_fmt adds the same content

This does change some of the prefixes of these messages
but it also does make them more consistent.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-06-28 11:19:58 -04:00
Yinghai Lu
ac2cbab21f x86: Don't panic if can not alloc buffer for swiotlb
Normal boot path on system with iommu support:
swiotlb buffer will be allocated early at first and then try to initialize
iommu, if iommu for intel or AMD could setup properly, swiotlb buffer
will be freed.

The early allocating is with bootmem, and could panic when we try to use
kdump with buffer above 4G only, or with memmap to limit mem under 4G.
for example: memmap=4095M$1M to remove memory under 4G.

According to Eric, add _nopanic version and no_iotlb_memory to fail
map single later if swiotlb is still needed.

-v2: don't pass nopanic, and use -ENOMEM return value according to Eric.
     panic early instead of using swiotlb_full to panic...according to Eric/Konrad.
-v3: make swiotlb_init to be notpanic, but will affect:
     arm64, ia64, powerpc, tile, unicore32, x86.
-v4: cleanup swiotlb_init by removing swiotlb_init_with_default_size.

Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1359058816-7615-36-git-send-email-yinghai@kernel.org
Reviewed-and-tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Cc: linux-mips@linux-mips.org
Cc: xen-devel@lists.xensource.com
Cc: virtualization@lists.linux-foundation.org
Cc: Shuah Khan <shuahkhan@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-01-29 19:36:53 -08:00
Alexander Duyck
fbfda893eb swiotlb: Use physical addresses instead of virtual in swiotlb_tbl_sync_single
This change makes it so that the sync functionality also uses physical
addresses.  This helps to further reduce the use of virt_to_phys and
phys_to_virt functions.

In order to clarify things since we now have 2 physical addresses in use
inside of swiotlb_tbl_sync_single I am renaming phys to orig_addr, and
dma_addr to tlb_addr.  This way is should be clear that orig_addr is
contained within io_orig_addr and tlb_addr is an address within the
io_tlb_addr buffer.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-10-30 09:32:07 -04:00
Alexander Duyck
61ca08c322 swiotlb: Use physical addresses for swiotlb_tbl_unmap_single
This change makes it so that the unmap functionality also uses physical
addresses.  This helps to further reduce the use of virt_to_phys and
phys_to_virt functions.

In order to clarify things since we now have 2 physical addresses in use
inside of swiotlb_tbl_unmap_single I am renaming phys to orig_addr, and
dma_addr to tlb_addr.  This way is should be clear that orig_addr is
contained within io_orig_addr and tlb_addr is an address within the
io_tlb_addr buffer.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-10-30 09:32:07 -04:00
Alexander Duyck
e05ed4d1fa swiotlb: Return physical addresses when calling swiotlb_tbl_map_single
This change makes it so that swiotlb_tbl_map_single will return a physical
address instead of a virtual address when called.  The advantage to this once
again is that we are avoiding a number of virt_to_phys and phys_to_virt
translations by working with everything as a physical address.

One change I had to make in order to support using physical addresses is that
I could no longer trust 0 to be a invalid physical address on all platforms.
So instead I made it so that ~0 is returned on error.  This should never be a
valid return value as it implies that only one byte would be available for
use.

In order to clarify things since we now have 2 physical addresses in use
inside of swiotlb_tbl_map_single I am renaming phys to orig_addr, and
dma_addr to tlb_addr.  This way is should be clear that orig_addr is
contained within io_orig_addr and tlb_addr is an address within the
io_tlb_addr buffer.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-10-30 09:32:06 -04:00
Konrad Rzeszutek Wilk
a5f9515570 Merge branch 'stable/late-swiotlb.v3.3' into stable/for-linus-3.7
* stable/late-swiotlb.v3.3:
  xen/swiotlb: Fix compile warnings when using plain integer instead of NULL pointer.
  xen/swiotlb: Remove functions not needed anymore.
  xen/pcifront: Use Xen-SWIOTLB when initting if required.
  xen/swiotlb: For early initialization, return zero on success.
  xen/swiotlb: Use the swiotlb_late_init_with_tbl to init Xen-SWIOTLB late when PV PCI is used.
  xen/swiotlb: Move the error strings to its own function.
  xen/swiotlb: Move the nr_tbl determination in its own function.
  swiotlb: add the late swiotlb initialization function with iotlb memory
  xen/swiotlb: With more than 4GB on 64-bit, disable the native SWIOTLB.
  xen/swiotlb: Simplify the logic.

Conflicts:
	arch/x86/xen/pci-swiotlb-xen.c

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-09-22 20:01:24 -04:00
Konrad Rzeszutek Wilk
e815f45e6e xen/swiotlb: Remove functions not needed anymore.
Sparse warns us off:
drivers/xen/swiotlb-xen.c:506:1: warning: symbol 'xen_swiotlb_map_sg' was not declared. Should it be static?
drivers/xen/swiotlb-xen.c:534:1: warning: symbol 'xen_swiotlb_unmap_sg' was not declared. Should it be static?

and it looks like we do not need this function at all.

Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-09-17 13:00:43 -04:00
Konrad Rzeszutek Wilk
c468bdee28 xen/swiotlb: For early initialization, return zero on success.
If everything is setup properly we would return -ENOMEM since
rc by default is set to that value. Lets not do that and return
a proper return code.

Note: The reason the early code needs this special treatment
is that it SWIOTLB library call does not return anything (and
had it failed it would call panic()) - but our function does.

Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-09-17 13:00:41 -04:00
Konrad Rzeszutek Wilk
b827760053 xen/swiotlb: Use the swiotlb_late_init_with_tbl to init Xen-SWIOTLB late when PV PCI is used.
With this patch we provide the functionality to initialize the
Xen-SWIOTLB late in the bootup cycle - specifically for
Xen PCI-frontend. We still will work if the user had
supplied 'iommu=soft' on the Linux command line.

Note: We cannot depend on after_bootmem to automatically
determine whether this is early or not. This is because
when PCI IOMMUs are initialized it is after after_bootmem but
before a lot of "other" subsystems are initialized.

CC: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
[v1: Fix smatch warnings]
[v2: Added check for xen_swiotlb]
[v3: Rebased with new xen-swiotlb changes]
[v4: squashed xen/swiotlb: Depending on after_bootmem is not correct in]
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-09-17 12:58:16 -04:00
Konrad Rzeszutek Wilk
5bab7864b1 xen/swiotlb: Move the error strings to its own function.
That way we can more easily reuse those errors when using the
late SWIOTLB init.

Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-09-17 10:14:59 -04:00
Konrad Rzeszutek Wilk
1cef36a529 xen/swiotlb: Move the nr_tbl determination in its own function.
Moving the function out of the way to prepare for the late
SWIOTLB init.

Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-09-17 10:14:54 -04:00
Konrad Rzeszutek Wilk
25a765b7f0 Merge branch 'x86/platform' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into stable/for-linus-3.7
* 'x86/platform' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (9690 commits)
  x86: Document x86_init.paging.pagetable_init()
  x86: xen: Cleanup and remove x86_init.paging.pagetable_setup_done()
  x86: Move paging_init() call to x86_init.paging.pagetable_init()
  x86: Rename pagetable_setup_start() to pagetable_init()
  x86: Remove base argument from x86_init.paging.pagetable_setup_start
  Linux 3.6-rc5
  HID: tpkbd: work even if the new Lenovo Keyboard driver is not configured
  Remove user-triggerable BUG from mpol_to_str
  xen/pciback: Fix proper FLR steps.
  uml: fix compile error in deliver_alarm()
  dj: memory scribble in logi_dj
  Fix order of arguments to compat_put_time[spec|val]
  xen: Use correct masking in xen_swiotlb_alloc_coherent.
  xen: fix logical error in tlb flushing
  xen/p2m: Fix one-off error in checking the P2M tree directory.
  powerpc: Don't use __put_user() in patch_instruction
  powerpc: Make sure IPI handlers see data written by IPI senders
  powerpc: Restore correct DSCR in context switch
  powerpc: Fix DSCR inheritance in copy_thread()
  powerpc: Keep thread.dscr and thread.dscr_inherit in sync
  ...
2012-09-12 11:14:33 -04:00
Ronny Hegewald
b5031ed1be xen: Use correct masking in xen_swiotlb_alloc_coherent.
When running 32-bit pvops-dom0 and a driver tries to allocate a coherent
DMA-memory the xen swiotlb-implementation returned memory beyond 4GB.

The underlaying reason is that if the supplied driver passes in a
DMA_BIT_MASK(64) ( hwdev->coherent_dma_mask is set to 0xffffffffffffffff)
our dma_mask will be u64 set to 0xffffffffffffffff even if we set it to
DMA_BIT_MASK(32) previously. Meaning we do not reset the upper bits.
By using the dma_alloc_coherent_mask function - it does the proper casting
and we get 0xfffffffff.

This caused not working sound on a system with 4 GB and a 64-bit
compatible sound-card with sets the DMA-mask to 64bit.

On bare-metal and the forward-ported xen-dom0 patches from OpenSuse a coherent
DMA-memory is always allocated inside the 32-bit address-range by calling
dma_alloc_coherent_mask.

This patch adds the same functionality to xen swiotlb and is a rebase of the
original patch from Ronny Hegewald which never got upstream b/c the
underlaying reason was not understood until now.

The original email with the original patch is in:
http://old-list-archives.xen.org/archives/html/xen-devel/2010-02/msg00038.html
the original thread from where the discussion started is in:
http://old-list-archives.xen.org/archives/html/xen-devel/2010-01/msg00928.html

Signed-off-by: Ronny Hegewald <ronny.hegewald@online.de>
Signed-off-by: Stefano Panella <stefano.panella@citrix.com>
Acked-By: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: stable@vger.kernel.org
2012-09-05 10:50:27 -04:00
Konrad Rzeszutek Wilk
a8752fd9a4 xen/swiotlb: Remove functions not needed anymore.
Sparse warns us off:
drivers/xen/swiotlb-xen.c:506:1: warning: symbol 'xen_swiotlb_map_sg' was not declared. Should it be static?
drivers/xen/swiotlb-xen.c:534:1: warning: symbol 'xen_swiotlb_unmap_sg' was not declared. Should it be static?

and it looks like we do not need this function at all.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-08-23 10:18:56 -04:00
Konrad Rzeszutek Wilk
b8b0f559c7 xen/apic/xenbus/swiotlb/pcifront/grant/tmem: Make functions or variables static.
There is no need for those functions/variables to be visible. Make them
static and also fix the compile warnings of this sort:

drivers/xen/<some file>.c: warning: symbol '<blah>' was not declared. Should it be static?

Some of them just require including the header file that
declares the functions.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-08-21 14:50:03 -04:00
Andrzej Pietrasiewicz
baa676fcf8 X86 & IA64: adapt for dma_map_ops changes
Adapt core x86 and IA64 architecture code for dma_map_ops changes: replace
alloc/free_coherent with generic alloc/free methods.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
[removed swiotlb related changes and replaced it with wrappers,
 merged with IA64 patch to avoid inter-patch dependences in intel-iommu code]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Tony Luck <tony.luck@intel.com>
2012-03-28 16:36:31 +02:00
Dave Airlie
1fbe6f625f Merge tag 'v3.2-rc6' of /home/airlied/devel/kernel/linux-2.6 into drm-core-next
Merge in the upstream tree to bring in the mainline fixes.

Conflicts:
	drivers/gpu/drm/exynos/exynos_drm_fbdev.c
	drivers/gpu/drm/nouveau/nouveau_sgdma.c
2011-12-20 14:43:53 +00:00
Konrad Rzeszutek Wilk
63a741757d xen/swiotlb: Use page alignment for early buffer allocation.
This fixes an odd bug found on a Dell PowerEdge 1850/0RC130
(BIOS A05 01/09/2006) where all of the modules doing pci_set_dma_mask
would fail with:

ata_piix 0000:00:1f.1: enabling device (0005 -> 0007)
ata_piix 0000:00:1f.1: can't derive routing for PCI INT A
ata_piix 0000:00:1f.1: BMDMA: failed to set dma mask, falling back to PIO

The issue was the Xen-SWIOTLB was allocated such as that the end of
buffer was stradling a page (and also above 4GB). The fix was
spotted by Kalev Leonid  which was to piggyback on git commit
e79f86b2ef "swiotlb: Use page alignment
for early buffer allocation" which:

	We could call free_bootmem_late() if swiotlb is not used, and
	it will shrink to page alignment.

	So alloc them with page alignment at first, to avoid lose two pages

And doing that fixes the outstanding issue.

CC: stable@kernel.org
Suggested-by: "Kalev, Leonid" <Leonid.Kalev@ca.com>
Reported-and-Tested-by: "Taylor, Neal E" <Neal.Taylor@ca.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-12-15 11:28:46 -05:00
Konrad Rzeszutek Wilk
f21ffe9f6d swiotlb: Expose swiotlb_nr_tlb function to modules
As a mechanism to detect whether SWIOTLB is enabled or not.
We also fix the spelling - it was swioltb instead of
swiotlb.

CC: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
[v1: Ripped out swiotlb_enabled]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-12-06 10:38:03 +00:00
Paul Gortmaker
63c9744b9a xen: Add export.h for THIS_MODULE/EXPORT_SYMBOL to various xen users.
Things like THIS_MODULE and EXPORT_SYMBOL were simply everywhere
because module.h was also everywhere.  But we are fixing the latter.
So we need to call out the real users in advance.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:32:11 -04:00
Konrad Rzeszutek Wilk
6810df88dc xen-swiotlb: When doing coherent alloc/dealloc check before swizzling the MFNs.
The process to swizzle a Machine Frame Number (MFN) is not always
necessary. Especially if we know that we actually do not have to do it.
In this patch we check the MFN against the device's coherent
DMA mask and if the requested page(s) are contingous. If it all checks
out we will just return the bus addr without doing the memory
swizzle.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-08-26 12:10:42 -04:00
Randy Dunlap
61ca79831c xen-swiotlb: fix printk and panic args
Fix printk() and panic() args [swap them] to fix build warnings:

drivers/xen/swiotlb-xen.c:201: warning: format '%s' expects type 'char *', but argument 2 has type 'int'
drivers/xen/swiotlb-xen.c:201: warning: format '%d' expects type 'int', but argument 3 has type 'char *'
drivers/xen/swiotlb-xen.c:202: warning: format '%s' expects type 'char *', but argument 2 has type 'int'
drivers/xen/swiotlb-xen.c:202: warning: format '%d' expects type 'int', but argument 3 has type 'char *'

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-08-26 12:10:17 -04:00
Konrad Rzeszutek Wilk
ab2a47bd24 xen-swiotlb: Fix wrong panic.
Propagate the baremetal git commit "swiotlb: fix wrong panic"
(fba99fa38b) in the Xen-SWIOTLB version.
wherein swiotlb's map_page wrongly calls panic() when it can't find
a buffer fit for device's dma mask.  It should return an error instead.

Devices with an odd dma mask (i.e.  under 4G) like b44 network card hit
this bug (the system crashes):

http://marc.info/?l=linux-kernel&m=129648943830106&w=2

If xen-swiotlb returns an error, b44 driver can use the own bouncing
mechanism.

CC: stable@kernel.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-08-26 12:10:16 -04:00
Konrad Rzeszutek Wilk
f4b2f07b2e xen-swiotlb: Retry up three times to allocate Xen-SWIOTLB
We can fail seting up Xen-SWIOTLB if:
 - The host does not have enough contiguous DMA32 memory available
   (can happen on a machine that has fragmented memory from starting,
   stopping many guests).
 - Not enough low memory (almost never happens).

We retry allocating and exchanging the swath of contiguous memory
up to three times. Each time we decrease the amount we need  - the
minimum being of 2MB.

If we compleltly fail, we will print the reason for failure on the Xen
console on top of doing it to earlyprintk=xen console.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-08-26 12:10:15 -04:00
Linus Torvalds
361932bf84 Merge branch 'stable/xen-swiotlb.bugfix' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb-2.6
* 'stable/xen-swiotlb.bugfix' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb-2.6:
  swiotlb: Export swioltb_nr_tbl and utilize it as appropiate.
2011-06-09 12:52:44 -07:00
FUJITA Tomonori
5f98ecdbce swiotlb: Export swioltb_nr_tbl and utilize it as appropiate.
By default the io_tlb_nslabs is set to zero, and gets set to
whatever value is passed in via swiotlb_init_with_tbl function.
The default value passed in is 64MB. However, if the user provides
the 'swiotlb=<nslabs>' the default value is ignored and
the value provided by the user is used... Except when the SWIOTLB
is used under Xen - there the default value of 64MB is used and
the Xen-SWIOTLB has no mechanism to get the 'io_tlb_nslabs' filled
out by setup_io_tlb_npages functions. This patch provides a function
for the Xen-SWIOTLB to call to see if the io_tlb_nslabs is set
and if so use that value.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-06-06 15:41:16 -04:00
Justin P. Mattock
6eab04a876 treewide: remove extra semicolons
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-04-10 17:01:05 +02:00
Konrad Rzeszutek Wilk
b097186fd2 swiotlb-xen: SWIOTLB library for Xen PV guest with PCI passthrough.
This patchset:

PV guests under Xen are running in an non-contiguous memory architecture.

When PCI pass-through is utilized, this necessitates an IOMMU for
translating bus (DMA) to virtual and vice-versa and also providing a
mechanism to have contiguous pages for device drivers operations (say DMA
operations).

Specifically, under Xen the Linux idea of pages is an illusion. It
assumes that pages start at zero and go up to the available memory. To
help with that, the Linux Xen MMU provides a lookup mechanism to
translate the page frame numbers (PFN) to machine frame numbers (MFN)
and vice-versa. The MFN are the "real" frame numbers. Furthermore
memory is not contiguous. Xen hypervisor stitches memory for guests
from different pools, which means there is no guarantee that PFN==MFN
and PFN+1==MFN+1. Lastly with Xen 4.0, pages (in debug mode) are
allocated in descending order (high to low), meaning the guest might
never get any MFN's under the 4GB mark.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Albert Herranz <albert_herranz@yahoo.es>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
2010-07-27 11:51:00 -04:00