The .probe_finalize() call-back of some IOMMU drivers calls into
arm_iommu_attach_device(). This function will call back into the
IOMMU core code, where it tries to take group->mutex again, resulting
in a deadlock.

As there is no reason why .probe_finalize() needs to be called under
that mutex, move it after the lock has been released to fix the
deadlock.

Fixes: deac0b3b ("iommu: Split off default domain allocation from group assignment")
Reported-by: NYong Wu <yong.wu@mediatek.com>
Tested-by: NYong Wu <yong.wu@mediatek.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Cc: Yong Wu <yong.wu@mediatek.com>
Link: https://lore.kernel.org/r/20200519132824.15163-1-joro@8bytes.org

The host1x bus implemented on Tegra SoCs is primarily an abstraction to
create logical device from multiple platform devices. Since the devices
in such a setup are typically hierarchical, DMA setup still needs to be
done so that DMA masks can be properly inherited, but we don't actually
want to attach the host1x logical devices to any IOMMU. The platform
devices that make up the logical device are responsible for memory bus
transactions, so it is them that will need to be attached to the IOMMU.

Add a check to __iommu_probe_device() that aborts IOMMU setup early for
busses that don't have the IOMMU operations pointer set since they will
cause a crash otherwise.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20200511161000.3853342-1-thierry.reding@gmail.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

The function is now only used in IOMMU core code and shouldn't be used
outside of it anyway, so remove the export for it.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-35-joro@8bytes.orgSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Move the calls to dev_iommu_get() and try_module_get() into
__iommu_probe_device(), so that the callers don't have to do it on
their own.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-34-joro@8bytes.orgSigned-off-by: NJoerg Roedel <jroedel@suse.de>

All drivers are converted to use the probe/release_device()
call-backs, so the add_device/remove_device() pointers are unused and
the code using them can be removed.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-33-joro@8bytes.orgSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Add a check to the bus_iommu_probe() call-path to make sure it ignores
devices which have already been successfully probed. Then export the
bus_iommu_probe() function so it can be used by IOMMU drivers.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-14-joro@8bytes.orgSigned-off-by: NJoerg Roedel <jroedel@suse.de>

After the previous changes the iommu group may not have a default
domain when iommu_group_add_device() is called. With no default domain
iommu_group_create_direct_mappings() will do nothing and no direct
mappings will be created.

Rename iommu_group_create_direct_mappings() to
iommu_create_device_direct_mappings() to better reflect that the
function creates direct mappings only for one device and not for all
devices in the group. Then move the call to the places where a default
domain actually exists.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-13-joro@8bytes.orgSigned-off-by: NJoerg Roedel <jroedel@suse.de>

When a bus is initialized with iommu-ops, all devices on the bus are
scanned and iommu-groups are allocated for them, and each groups will
also get a default domain allocated.

Until now this happened as soon as the group was created and the first
device added to it. When other devices with different default domain
requirements were added to the group later on, the default domain was
re-allocated, if possible.

This resulted in some back and forth and unnecessary allocations, so
change the flow to defer default domain allocation until all devices
have been added to their respective IOMMU groups.

The default domains are allocated for newly allocated groups after
each device on the bus is handled and was probed by the IOMMU driver.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-12-joro@8bytes.orgSigned-off-by: NJoerg Roedel <jroedel@suse.de>

This makes it easier to remove to old code-path when all drivers are
converted. As a side effect that it also fixes the error cleanup
path.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-11-joro@8bytes.orgSigned-off-by: NJoerg Roedel <jroedel@suse.de>

This is needed to defer default_domain allocation for new IOMMU groups
until all devices have been added to the group.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-10-joro@8bytes.orgSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Well, not really. The call to iommu_alloc_default_domain() in
iommu_group_get_for_dev() has to stay around as long as there are
IOMMU drivers using the add/remove_device() call-backs instead of
probe/release_device().

Those drivers expect that iommu_group_get_for_dev() returns the device
attached to a group and the group set up with a default domain (and
the device attached to the groups current domain).

But when all drivers are converted this compatability mess can be
removed.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-9-joro@8bytes.orgSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Add call-backs to 'struct iommu_ops' as an alternative to the
add_device() and remove_device() call-backs, which will be removed when
all drivers are converted.

The new call-backs will not setup IOMMU groups and domains anymore,
so also add a probe_finalize() call-back where the IOMMU driver can do
per-device setup work which require the device to be set up with a
group and a domain.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-8-joro@8bytes.orgSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Some devices are reqired to use a specific type (identity or dma)
of default domain when they are used with a vendor iommu. When the
system level default domain type is different from it, the vendor
iommu driver has to request a new default domain with
iommu_request_dma_domain_for_dev() and iommu_request_dm_for_dev()
in the add_dev() callback. Unfortunately, these two helpers only
work when the group hasn't been assigned to any other devices,
hence, some vendor iommu driver has to use a private domain if
it fails to request a new default one.

This adds def_domain_type() callback in the iommu_ops, so that
any special requirement of default domain for a device could be
aware by the iommu generic layer.
Signed-off-by: NSai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: NLu Baolu <baolu.lu@linux.intel.com>
[ jroedel@suse.de: Added iommu_get_def_domain_type() function and use
                   it to allocate the default domain ]
Co-developed-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-3-joro@8bytes.orgSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Move the code out of iommu_group_get_for_dev() into a separate
function.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-2-joro@8bytes.orgSigned-off-by: NJoerg Roedel <jroedel@suse.de>

In commit a7ba5c3d ("drivers/iommu: Export core IOMMU API symbols to
permit modular drivers") a bunch of iommu symbols were exported, all
with _GPL markings except iommu_group_get_for_dev().  That export should
also be _GPL like the others.

Fixes: a7ba5c3d ("drivers/iommu: Export core IOMMU API symbols to permit modular drivers")
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: NWill Deacon <will@kernel.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: John Garry <john.garry@huawei.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200430120120.2948448-1-gregkh@linuxfoundation.orgSigned-off-by: NJoerg Roedel <jroedel@suse.de>

In iommu_probe_device(), we would invoke dev_iommu_free() to free the
dev->iommu after the ->add_device() returns failure. But after commit
72acd9df ("iommu: Move iommu_fwspec to struct dev_iommu"), we also
need to free the iommu_fwspec before the dev->iommu is freed. This fixes
the following memory leak reported by kmemleak:
  unreferenced object 0xffff000bc836c700 (size 128):
    comm "swapper/0", pid 1, jiffies 4294896304 (age 782.120s)
    hex dump (first 32 bytes):
      00 00 00 00 00 00 00 00 d8 cd 9b ff 0b 00 ff ff  ................
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    backtrace:
      [<00000000df34077b>] kmem_cache_alloc_trace+0x244/0x4b0
      [<000000000e560ac0>] iommu_fwspec_init+0x7c/0xb0
      [<0000000075eda275>] of_iommu_xlate+0x80/0xe8
      [<00000000728d6bf9>] of_pci_iommu_init+0xb0/0xb8
      [<00000000d001fe6f>] pci_for_each_dma_alias+0x48/0x190
      [<000000006db6bbce>] of_iommu_configure+0x1ac/0x1d0
      [<00000000634745f8>] of_dma_configure+0xdc/0x220
      [<000000002cbc8ba0>] pci_dma_configure+0x50/0x78
      [<00000000cdf6e193>] really_probe+0x8c/0x340
      [<00000000fddddc46>] driver_probe_device+0x60/0xf8
      [<0000000061bcdb51>] __device_attach_driver+0x8c/0xd0
      [<000000009b9ff58e>] bus_for_each_drv+0x80/0xd0
      [<000000004b9c8aa3>] __device_attach+0xec/0x148
      [<00000000a5c13bf3>] device_attach+0x1c/0x28
      [<000000005071e151>] pci_bus_add_device+0x58/0xd0
      [<000000002d4f87d1>] pci_bus_add_devices+0x40/0x90

Fixes: 72acd9df ("iommu: Move iommu_fwspec to struct dev_iommu")
Signed-off-by: NKevin Hao <haokexin@gmail.com>
Link: https://lore.kernel.org/r/20200402143749.40500-1-haokexin@gmail.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Move the iommu_fwspec pointer in struct device into struct dev_iommu.
This is a step in the effort to reduce the iommu related pointers in
struct device to one.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: Will Deacon <will@kernel.org> # arm-smmu
Reviewed-by: NJean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20200326150841.10083-7-joro@8bytes.org

The term dev_iommu aligns better with other existing structures and
their accessor functions.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: Will Deacon <will@kernel.org> # arm-smmu
Reviewed-by: NJean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20200326150841.10083-6-joro@8bytes.org

Although the 1-element array was a typical pre-C99 way to implement
variable-length structures, and indeed is a fundamental construct in the
APIs of certain other popular platforms, there's no good reason for it
here (and in particular the sizeof() trick is far too "clever" for its
own good). We can just as easily implement iommu_fwspec's preallocation
behaviour using a standard flexible array member, so let's make it look
the way most readers would expect.
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

This adds the missing teardown step that removes the device link from
the group when the device addition fails.
Signed-off-by: NJon Derrick <jonathan.derrick@intel.com>
Fixes: 797a8b4d ("iommu: Handle default domain attach failure")
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

Implement a generic function for removing reserved regions. This can be
used by drivers that don't do anything fancy with these regions other
than allocating memory for them.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

'bus_set_iommu()' allows IOMMU drivers to register their ops for a given
bus type. Unfortunately, it then doesn't allow them to be removed, which
is necessary for modular drivers to shutdown cleanly so that they can be
reloaded later on.

Allow 'bus_set_iommu()' to take a NULL 'ops' argument, which clear the
ops pointer for the selected bus_type.
Signed-off-by: NWill Deacon <will@kernel.org>
Tested-by: John Garry <john.garry@huawei.com> # smmu v3
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

To avoid accidental removal of an active IOMMU driver module, take a
reference to the driver module in 'iommu_probe_device()' immediately
prior to invoking the '->add_device()' callback and hold it until the
after the device has been removed by '->remove_device()'.
Suggested-by: NJoerg Roedel <joro@8bytes.org>
Signed-off-by: NWill Deacon <will@kernel.org>
Tested-by: John Garry <john.garry@huawei.com> # smmu v3
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

Building IOMMU drivers as modules requires that the core IOMMU API
symbols are exported as GPL symbols.
Signed-off-by: NWill Deacon <will@kernel.org>
Tested-by: John Garry <john.garry@huawei.com> # smmu v3
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

iommu_group_create_direct_mappings uses group->default_domain, but
right after it is called, request_default_domain_for_dev calls
iommu_domain_free for the default domain, and sets the group default
domain to a different domain. Move the
iommu_group_create_direct_mappings call to after the group default
domain is set, so the direct mappings get associated with that domain.

Cc: Joerg Roedel <jroedel@suse.de>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: stable@vger.kernel.org
Fixes: 7423e017 ("iommu: Add API to request DMA domain for device")
Signed-off-by: NJerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

In case the new region gets merged into another one, the nr list node is
freed.  Checking its type while completing the merge algorithm leads to
a use-after-free.  Use new->type instead.

Fixes: 4dbd258f ("iommu: Revisit iommu_insert_resv_region() implementation")
Signed-off-by: NEric Auger <eric.auger@redhat.com>
Reported-by: NQian Cai <cai@lca.pw>
Reviewed-by: NJerry Snitselaar <jsnitsel@redhat.com>
Cc: Stable <stable@vger.kernel.org> #v5.3+
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Guest shared virtual address (SVA) may require host to shadow guest
PASID tables. Guest PASID can also be allocated from the host via
enlightened interfaces. In this case, guest needs to bind the guest
mm, i.e. cr3 in guest physical address to the actual PASID table in
the host IOMMU. Nesting will be turned on such that guest virtual
address can go through a two level translation:
- 1st level translates GVA to GPA
- 2nd level translates GPA to HPA
This patch introduces APIs to bind guest PASID data to the assigned
device entry in the physical IOMMU. See the diagram below for usage
explanation.

    .-------------.  .---------------------------.
    |   vIOMMU    |  | Guest process mm, FL only |
    |             |  '---------------------------'
    .----------------/
    | PASID Entry |--- PASID cache flush -
    '-------------'                       |
    |             |                       V
    |             |                      GP
    '-------------'
Guest
------| Shadow |----------------------- GP->HP* ---------
      v        v                          |
Host                                      v
    .-------------.  .----------------------.
    |   pIOMMU    |  | Bind FL for GVA-GPA  |
    |             |  '----------------------'
    .----------------/  |
    | PASID Entry |     V (Nested xlate)
    '----------------\.---------------------.
    |             |   |Set SL to GPA-HPA    |
    |             |   '---------------------'
    '-------------'

Where:
 - FL = First level/stage one page tables
 - SL = Second level/stage two page tables
 - GP = Guest PASID
 - HP = Host PASID
* Conversion needed if non-identity GP-HP mapping option is chosen.
Signed-off-by: NJacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: NLiu Yi L <yi.l.liu@intel.com>
Reviewed-by: NJean-Philippe Brucker <jean-philippe@linaro.com>
Reviewed-by: NJean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: NEric Auger <eric.auger@redhat.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

In any virtualization use case, when the first translation stage
is "owned" by the guest OS, the host IOMMU driver has no knowledge
of caching structure updates unless the guest invalidation activities
are trapped by the virtualizer and passed down to the host.

Since the invalidation data can be obtained from user space and will be
written into physical IOMMU, we must allow security check at various
layers. Therefore, generic invalidation data format are proposed here,
model specific IOMMU drivers need to convert them into their own format.
Signed-off-by: NYi L Liu <yi.l.liu@intel.com>
Signed-off-by: NJacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: NAshok Raj <ashok.raj@intel.com>
Signed-off-by: NEric Auger <eric.auger@redhat.com>
Signed-off-by: NJean-Philippe Brucker <jean-philippe@linaro.com>
Reviewed-by: NJean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: NEric Auger <eric.auger@redhat.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

Add a gfp_t parameter to the iommu_ops::map function.
Remove the needless locking in the AMD iommu driver.

The iommu_ops::map function (or the iommu_map function which calls it)
was always supposed to be sleepable (according to Joerg's comment in
this thread: https://lore.kernel.org/patchwork/patch/977520/ ) and so
should probably have had a "might_sleep()" since it was written. However
currently the dma-iommu api can call iommu_map in an atomic context,
which it shouldn't do. This doesn't cause any problems because any iommu
driver which uses the dma-iommu api uses gfp_atomic in it's
iommu_ops::map function. But doing this wastes the memory allocators
atomic pools.
Signed-off-by: NTom Murphy <murphyt7@tcd.ie>
Reviewed-by: NRobin Murphy <robin.murphy@arm.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

Switch to the generic function mem_encrypt_active() because
sme_active() is x86 specific and can't be called from
generic code on other platforms than x86.

Fixes: 2cc13bb4 ("iommu: Disable passthrough mode when SME is active")
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

These comments are wrong. request_default_domain_for_dev doesn't just
handle direct mapped domains.
Signed-off-by: NTom Murphy <murphyt7@tcd.ie>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

Current implementation is recursive and in case of allocation
failure the existing @regions list is altered. A non recursive
version looks better for maintainability and simplifies the
error handling. We use a separate stack for overlapping segment
merging. The elements are sorted by start address and then by
type, if their start address match.

Note this new implementation may change the region order of
appearance in /sys/kernel/iommu_groups/<n>/reserved_regions
files but this order has never been documented, see
commit bc7d12b9 ("iommu: Implement reserved_regions
iommu-group sysfs file").
Signed-off-by: NEric Auger <eric.auger@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

Using Passthrough mode when SME is active causes certain
devices to use the SWIOTLB bounce buffer. The bounce buffer
code has an upper limit of 256kb for the size of DMA
allocations, which is too small for certain devices and
causes them to fail.

With this patch we enable IOMMU by default when SME is
active in the system, making the default configuration work
for more systems than it does now.

Users that don't want IOMMUs to be enabled still can disable
them with kernel parameters.
Reviewed-by: NTom Lendacky <thomas.lendacky@amd.com>
Tested-by: NTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

Set the default domain-type at runtime, not at compile-time.
This keeps default domain type setting in one place when we
have to change it at runtime.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

Introduce a subsys_initcall for IOMMU code and use it to
print the default domain type at boot.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

There are functions now to set the default domain type which
take care of updating other necessary state. Don't open-code
it in iommu_set_def_domain_type() and use those functions
instead.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

Add a couple of functions to allow changing the default
domain type from architecture code and a function for iommu
drivers to request whether the default domain is
passthrough.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

Introduce an extensible concept to remember when certain
configuration settings for the IOMMU code have been set on
the kernel command line.

This will be used later to prevent overwriting these
settings with other defaults.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

To allow IOMMU drivers to batch up TLB flushing operations and postpone
them until ->iotlb_sync() is called, extend the prototypes for the
->unmap() and ->iotlb_sync() IOMMU ops callbacks to take a pointer to
the current iommu_iotlb_gather structure.

All affected IOMMU drivers are updated, but there should be no
functional change since the extra parameter is ignored for now.
Signed-off-by: NWill Deacon <will@kernel.org>

To permit batching of TLB flushes across multiple calls to the IOMMU
driver's ->unmap() implementation, introduce a new structure for
tracking the address range to be flushed and the granularity at which
the flushing is required.

This is hooked into the IOMMU API and its caller are updated to make use
of the new structure. Subsequent patches will plumb this into the IOMMU
drivers as well, but for now the gathering information is ignored.
Signed-off-by: NWill Deacon <will@kernel.org>