Allocating and enabling a flush queue is in fact something we can
reasonably do while a DMA domain is active, without having to rebuild it
from scratch. Thus we can allow a strict -> non-strict transition from
sysfs without requiring to unbind the device's driver, which is of
particular interest to users who want to make selective relaxations to
critical devices like the one serving their root filesystem.

Disabling and draining a queue also seems technically possible to
achieve without rebuilding the whole domain, but would certainly be more
involved. Furthermore there's not such a clear use-case for tightening
up security *after* the device may already have done whatever it is that
you don't trust it not to do, so we only consider the relaxation case.
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/d652966348c78457c38bf18daf369272a4ebc2c9.1628682049.git.robin.murphy@arm.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

To parallel the sysfs behaviour, merge the new build-time option
for DMA domain strictness into the default domain type choice.
Suggested-by: NJoerg Roedel <joro@8bytes.org>
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: NJean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: NJohn Garry <john.garry@huawei.com>
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/d04af35b9c0f2a1d39605d7a9b451f5e1f0c7736.1628682049.git.robin.murphy@arm.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

When passthrough is enabled, the default strictness policy becomes
irrelevant, since any subsequent runtime override to a DMA domain type
now embodies an explicit choice of strictness as well. Save on noise by
only logging the default policy when it is meaningfully in effect.
Reviewed-by: NJohn Garry <john.garry@huawei.com>
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/9d2bcba880c6d517d0751ed8bd4960853030b4d7.1628682049.git.robin.murphy@arm.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

The sysfs interface for default domain types exists primarily so users
can choose the performance/security tradeoff relevant to their own
workload. As such, the choice between the policies for DMA domains fits
perfectly as an additional point on that scale - downgrading a
particular device from a strict default to non-strict may be enough to
let it reach the desired level of performance, while still retaining
more peace of mind than with a wide-open identity domain. Now that we've
abstracted non-strict mode as a distinct type of DMA domain, allow it to
be chosen through the user interface as well.
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: NJohn Garry <john.garry@huawei.com>
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/0e08da5ed4069fd3473cfbadda758ca983becdbf.1628682049.git.robin.murphy@arm.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Eliminate the iommu_get_dma_strict() indirection and pipe the
information through the domain type from the beginning. Besides
the flow simplification this also has several nice side-effects:

 - Automatically implies strict mode for untrusted devices by
   virtue of their IOMMU_DOMAIN_DMA override.
 - Ensures that we only end up using flush queues for drivers
   which are aware of them and can actually benefit.
 - Allows us to handle flush queue init failure by falling back
   to strict mode instead of leaving it to possibly blow up later.
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/47083d69155577f1367877b1594921948c366eb3.1628682049.git.robin.murphy@arm.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Promote the difference between strict and non-strict DMA domains from an
internal detail to a distinct domain feature and type, to pave the road
for exposing it through the sysfs default domain interface.
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: NJean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/08cd2afaf6b63c58ad49acec3517c9b32c2bb946.1628682049.git.robin.murphy@arm.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Now that everyone has converged on iommu-dma for IOMMU_DOMAIN_DMA
support, we can abandon the notion of drivers being responsible for the
cookie type, and consolidate all the management into the core code.

CC: Yong Wu <yong.wu@mediatek.com>
CC: Chunyan Zhang <chunyan.zhang@unisoc.com>
CC: Maxime Ripard <mripard@kernel.org>
Tested-by: NHeiko Stuebner <heiko@sntech.de>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Tested-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: NJean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/46a2c0e7419c7d1d931762dc7b6a69fa082d199a.1628682048.git.robin.murphy@arm.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

When two devices with same SID are getting probed concurrently through
iommu_probe_device(), the iommu_domain sometimes is getting allocated more
than once as call to iommu_alloc_default_domain() is not protected for
concurrency. Furthermore, it leads to each device holding a different
iommu_domain pointer, separate IOVA space and only one of the devices'
domain is used for translations from IOMMU. This causes accesses from other
device to fault or see incorrect translations.
Fix this by protecting iommu_alloc_default_domain() call with group->mutex
and let all devices with same SID share same iommu_domain.
Signed-off-by: NAshish Mhetre <amhetre@nvidia.com>
Link: https://lore.kernel.org/r/1628570641-9127-2-git-send-email-amhetre@nvidia.comSigned-off-by: NWill Deacon <will@kernel.org>

Convert to ssize_t return code so the return code from __iommu_map()
can be returned all the way down through dma_iommu_map_sg().
Signed-off-by: NLogan Gunthorpe <logang@deltatee.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

If probe_device is failing, iommu_group is not initialized because
iommu_group_add_device is not reached, so freeing it will result
in NULL pointer access.

iommu_bus_init
  ->bus_iommu_probe
      ->probe_iommu_group in for each:/* return -22 in fail case */
          ->iommu_probe_device
              ->__iommu_probe_device       /* return -22 here.*/
                  -> ops->probe_device          /* return -22 here.*/
                  -> iommu_group_get_for_dev
                        -> ops->device_group
                        -> iommu_group_add_device //good case
  ->remove_iommu_group  //in fail case, it will remove group
     ->iommu_release_device
         ->iommu_group_remove_device // here we don't have group

In my case ops->probe_device (mtk_iommu_probe_device from
mtk_iommu_v1.c) is due to failing fwspec->ops mismatch.

Fixes: d72e31c9 ("iommu: IOMMU Groups")
Signed-off-by: NFrank Wunderlich <frank-w@public-files.de>
Link: https://lore.kernel.org/r/20210731074737.4573-1-linux@fw-web.deSigned-off-by: NJoerg Roedel <jroedel@suse.de>

If people are going to insist on calling iommu_iova_to_phys()
pointlessly and expecting it to work, we can at least do ourselves a
favour by handling those cases in the core code, rather than repeatedly
across an inconsistent handful of drivers.

Since all the existing drivers implement the internal callback, and any
future ones are likely to want to work with iommu-dma which relies on
iova_to_phys a fair bit, we may as well remove that currently-redundant
check as well and consider it mandatory.
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/f564f3f6ff731b898ff7a898919bf871c2c7745a.1626354264.git.robin.murphy@arm.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

We only ever now set strict mode enabled in iommu_set_dma_strict(), so
just remove the argument.
Signed-off-by: NJohn Garry <john.garry@huawei.com>
Reviewed-by: NRobin Murphy <robin.murphy@arm.com>
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/1626088340-5838-7-git-send-email-john.garry@huawei.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

First, add build options IOMMU_DEFAULT_{LAZY|STRICT}, so that we have the
opportunity to set {lazy|strict} mode as default at build time. Then put
the two config options in an choice, as they are mutually exclusive.

[jpg: Make choice between strict and lazy only (and not passthrough)]
Signed-off-by: NZhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: NJohn Garry <john.garry@huawei.com>
Reviewed-by: NRobin Murphy <robin.murphy@arm.com>
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/1626088340-5838-4-git-send-email-john.garry@huawei.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

As well as the default domain type, it's useful to know whether strict
or lazy for DMA domains, so add this info in a separate print.

The (stict/lazy) mode may be also set via iommu.strict earlyparm, but
this will be processed prior to iommu_subsys_init(), so that print will be
accurate for drivers which don't set the mode via custom means.

For the drivers which set the mode via custom means - AMD and Intel drivers
- they maintain prints to inform a change in policy or that custom cmdline
methods to change policy are deprecated.
Signed-off-by: NJohn Garry <john.garry@huawei.com>
Reviewed-by: NRobin Murphy <robin.murphy@arm.com>
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/1626088340-5838-3-git-send-email-john.garry@huawei.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Since iommu_pgsize can calculate how many pages of the
same size can be mapped/unmapped before the next largest
page size boundary, add support for invoking an IOMMU
driver's map_pages() callback, if it provides one.
Signed-off-by: NIsaac J. Manjarres <isaacm@codeaurora.org>
Suggested-by: NWill Deacon <will@kernel.org>
Signed-off-by: NGeorgi Djakov <quic_c_gdjako@quicinc.com>
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/1623850736-389584-9-git-send-email-quic_c_gdjako@quicinc.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Extend iommu_pgsize() to populate an optional 'count' parameter so that
we can direct unmapping operation to the ->unmap_pages callback if it
has been provided by the driver.
Signed-off-by: NWill Deacon <will@kernel.org>
Signed-off-by: NIsaac J. Manjarres <isaacm@codeaurora.org>
Signed-off-by: NGeorgi Djakov <quic_c_gdjako@quicinc.com>
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/1623850736-389584-8-git-send-email-quic_c_gdjako@quicinc.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

The 'addr_merge' parameter to iommu_pgsize() is a fabricated address
intended to describe the alignment requirements to consider when
choosing an appropriate page size. On the iommu_map() path, this address
is the logical OR of the virtual and physical addresses.

Subsequent improvements to iommu_pgsize() will need to check the
alignment of the virtual and physical components of 'addr_merge'
independently, so pass them in as separate parameters and reconstruct
'addr_merge' locally.

No functional change.
Signed-off-by: NWill Deacon <will@kernel.org>
Signed-off-by: NIsaac J. Manjarres <isaacm@codeaurora.org>
Signed-off-by: NGeorgi Djakov <quic_c_gdjako@quicinc.com>
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/1623850736-389584-7-git-send-email-quic_c_gdjako@quicinc.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Avoid the potential for shifting values by amounts greater than the
width of their type by using a bitmap to compute page size in
iommu_pgsize().
Signed-off-by: NWill Deacon <will@kernel.org>
Signed-off-by: NIsaac J. Manjarres <isaacm@codeaurora.org>
Signed-off-by: NGeorgi Djakov <quic_c_gdjako@quicinc.com>
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/1623850736-389584-6-git-send-email-quic_c_gdjako@quicinc.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Function iommu_group_store_type() is the only caller of the static
function iommu_change_dev_def_domain() and has performed
"if (WARN_ON(!group))" detection before calling it. So the one here is
redundant.
Signed-off-by: NZhen Lei <thunder.leizhen@huawei.com>
Acked-by: NWill Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210513075815.6382-1-thunder.leizhen@huawei.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Rather than have separate opaque setter functions that are easy to
overlook and lead to repetitive boilerplate in drivers, let's pass the
relevant initialisation parameters directly to iommu_device_register().
Acked-by: NWill Deacon <will@kernel.org>
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/ab001b87c533b6f4db71eb90db6f888953986c36.1617285386.git.robin.murphy@arm.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Remove the now unused iommu attr infrastructure.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NWill Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210401155256.298656-21-hch@lst.deSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Use an explicit set_pgtable_quirks method instead that just passes
the actual quirk bitmask instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NWill Deacon <will@kernel.org>
Acked-by: NLi Yang <leoyang.li@nxp.com>
Link: https://lore.kernel.org/r/20210401155256.298656-20-hch@lst.deSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Instead make the global iommu_dma_strict paramete in iommu.c canonical by
exporting helpers to get and set it and use those directly in the drivers.

This make sure that the iommu.strict parameter also works for the AMD and
Intel IOMMU drivers on x86.  As those default to lazy flushing a new
IOMMU_CMD_LINE_STRICT is used to turn the value into a tristate to
represent the default if not overriden by an explicit parameter.

[ported on top of the other iommu_attr changes and added a few small
 missing bits]

Signed-off-by: Robin Murphy <robin.murphy@arm.com>.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210401155256.298656-19-hch@lst.deSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Don't obsfucate the trivial bit flag check.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NWill Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210401155256.298656-18-hch@lst.deSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Use an explicit enable_nesting method instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NWill Deacon <will@kernel.org>
Acked-by: NLi Yang <leoyang.li@nxp.com>
Link: https://lore.kernel.org/r/20210401155256.298656-17-hch@lst.deSigned-off-by: NJoerg Roedel <jroedel@suse.de>

The geometry information can be trivially queried from the iommu_domain
struture.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NWill Deacon <will@kernel.org>
Acked-by: NLi Yang <leoyang.li@nxp.com>
Link: https://lore.kernel.org/r/20210401155256.298656-16-hch@lst.deSigned-off-by: NJoerg Roedel <jroedel@suse.de>

DOMAIN_ATTR_PAGING is never used.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NWill Deacon <will@kernel.org>
Acked-by: NLi Yang <leoyang.li@nxp.com>
Link: https://lore.kernel.org/r/20210401155256.298656-15-hch@lst.deSigned-off-by: NJoerg Roedel <jroedel@suse.de>

The only thing that fsl_pamu_window_enable does for the current caller
is to fill in the prot value in the only dma_window structure, and to
propagate a few values from the iommu_domain_geometry struture into the
dma_window.  Remove the dma_window entirely, hardcode the prot value and
otherwise use the iommu_domain_geometry structure instead.

Remove the now unused ->domain_window_enable iommu method.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NLi Yang <leoyang.li@nxp.com>
Link: https://lore.kernel.org/r/20210401155256.298656-7-hch@lst.deSigned-off-by: NJoerg Roedel <jroedel@suse.de>

The device iommu probe/attach might have failed leaving dev->iommu
to NULL and device drivers may still invoke these functions resulting
in a crash in iommu vendor driver code.

Hence make sure we check that.

Fixes: a3a19592 ("iommu: Add APIs for multiple domains per device")
Signed-off-by: NShameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: NRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20210303173611.520-1-shameerali.kolothum.thodi@huawei.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Sleeping while atomic = bad.  Let's fix an obvious typo to try to avoid it.

The warning that was seen (on a downstream kernel with the problematic
patch backported):

 BUG: sleeping function called from invalid context at mm/page_alloc.c:4726
 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 9, name: ksoftirqd/0
 CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.4.93-12508-gc10c93e28e39 #1
 Call trace:
  dump_backtrace+0x0/0x154
  show_stack+0x20/0x2c
  dump_stack+0xa0/0xfc
  ___might_sleep+0x11c/0x12c
  __might_sleep+0x50/0x84
  __alloc_pages_nodemask+0xf8/0x2bc
  __arm_lpae_alloc_pages+0x48/0x1b4
  __arm_lpae_map+0x124/0x274
  __arm_lpae_map+0x1cc/0x274
  arm_lpae_map+0x140/0x170
  arm_smmu_map+0x78/0xbc
  __iommu_map+0xd4/0x210
  _iommu_map+0x4c/0x84
  iommu_map_atomic+0x44/0x58
  __iommu_dma_map+0x8c/0xc4
  iommu_dma_map_page+0xac/0xf0

Fixes: d8c1df02 ("iommu: Move iotlb_sync_map out from __iommu_map")
Signed-off-by: NDouglas Anderson <dianders@chromium.org>
Reviewed-by: NYong Wu <yong.wu@mediatek.com>
Acked-by: NWill Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210201170611.1.I64a7b62579287d668d7c89e105dcedf45d641063@changeidSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Currently, because domain attach allows to be deferred from iommu
driver to device driver, and when iommu initializes, the devices
on the bus will be scanned and the default groups will be allocated.

Due to the above changes, some devices could be added to the same
group as below:

[    3.859417] pci 0000:01:00.0: Adding to iommu group 16
[    3.864572] pci 0000:01:00.1: Adding to iommu group 16
[    3.869738] pci 0000:02:00.0: Adding to iommu group 17
[    3.874892] pci 0000:02:00.1: Adding to iommu group 17

But when attaching these devices, it doesn't allow that a group has
more than one device, otherwise it will return an error. This conflicts
with the deferred attaching. Unfortunately, it has two devices in the
same group for my side, for example:

[    9.627014] iommu_group_device_count(): device name[0]:0000:01:00.0
[    9.633545] iommu_group_device_count(): device name[1]:0000:01:00.1
...
[   10.255609] iommu_group_device_count(): device name[0]:0000:02:00.0
[   10.262144] iommu_group_device_count(): device name[1]:0000:02:00.1

Finally, which caused the failure of tg3 driver when tg3 driver calls
the dma_alloc_coherent() to allocate coherent memory in the tg3_test_dma().

[    9.660310] tg3 0000:01:00.0: DMA engine test failed, aborting
[    9.754085] tg3: probe of 0000:01:00.0 failed with error -12
[    9.997512] tg3 0000:01:00.1: DMA engine test failed, aborting
[   10.043053] tg3: probe of 0000:01:00.1 failed with error -12
[   10.288905] tg3 0000:02:00.0: DMA engine test failed, aborting
[   10.334070] tg3: probe of 0000:02:00.0 failed with error -12
[   10.578303] tg3 0000:02:00.1: DMA engine test failed, aborting
[   10.622629] tg3: probe of 0000:02:00.1 failed with error -12

In addition, the similar situations also occur in other drivers such
as the bnxt_en driver. That can be reproduced easily in kdump kernel
when SME is active.

Let's move the handling currently in iommu_dma_deferred_attach() into
the iommu core code so that it can call the __iommu_attach_device()
directly instead of the iommu_attach_device(). The external interface
iommu_attach_device() is not suitable for handling this situation.
Signed-off-by: NLianbo Jiang <lijiang@redhat.com>
Reviewed-by: NRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20210126115337.20068-3-lijiang@redhat.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

iotlb_sync_map allow IOMMU drivers tlb sync after completing the whole
mapping. This patch adds iova and size as the parameters in it. then the
IOMMU driver could flush tlb with the whole range once after iova mapping
to improve performance.
Signed-off-by: NYong Wu <yong.wu@mediatek.com>
Reviewed-by: NRobin Murphy <robin.murphy@arm.com>
Acked-by: NWill Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210107122909.16317-3-yong.wu@mediatek.comSigned-off-by: NWill Deacon <will@kernel.org>

In the end of __iommu_map, It alway call iotlb_sync_map.

This patch moves iotlb_sync_map out from __iommu_map since it is
unnecessary to call this for each sg segment especially iotlb_sync_map
is flush tlb all currently. Add a little helper _iommu_map for this.
Signed-off-by: NYong Wu <yong.wu@mediatek.com>
Reviewed-by: NRobin Murphy <robin.murphy@arm.com>
Acked-by: NWill Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210107122909.16317-2-yong.wu@mediatek.comSigned-off-by: NWill Deacon <will@kernel.org>

Function iommu_dev_has_feature() has never been referenced in the tree,
and there does not appear to be anything coming soon to use it, so delete
it.
Signed-off-by: NJohn Garry <john.garry@huawei.com>
Acked-by: NWill Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/1609940111-28563-7-git-send-email-john.garry@huawei.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Function iommu_domain_window_disable() is not referenced in the tree, so
delete it.
Signed-off-by: NJohn Garry <john.garry@huawei.com>
Acked-by: NWill Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/1609940111-28563-6-git-send-email-john.garry@huawei.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Function iommu_map_sg_atomic() is only referenced in dma-iommu.c, which
can only be built-in, so stop exporting.
Signed-off-by: NJohn Garry <john.garry@huawei.com>
Acked-by: NWill Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/1609940111-28563-5-git-send-email-john.garry@huawei.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

Currently direct_mapping always use the smallest pgsize which is SZ_4K
normally to mapping. This is unnecessary. we could gather the size, and
call iommu_map then, iommu_map could decide how to map better with the
just right pgsize.

>From the original comment, we should take care overlap, otherwise,
iommu_map may return -EEXIST. In this overlap case, we should map the
previous region before overlap firstly. then map the left part.

Each a iommu device will call this direct_mapping when its iommu
initialize, This patch is effective to improve the boot/initialization
time especially while it only needs level 1 mapping.
Signed-off-by: NAnan Sun <anan.sun@mediatek.com>
Signed-off-by: NYong Wu <yong.wu@mediatek.com>
Link: https://lore.kernel.org/r/20201207093553.8635-1-yong.wu@mediatek.comSigned-off-by: NWill Deacon <will@kernel.org>

Although iommu_group_get() in iommu_probe_device() will always succeed
thanks to __iommu_probe_device() creating the group if it's not present,
it's still worth initialising 'ret' to -ENODEV in case this path is
reachable in the future.

For now, this patch results in no functional change.
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20201126133825.3643852-1-yangyingliang@huawei.comSigned-off-by: NWill Deacon <will@kernel.org>

"/sys/kernel/iommu_groups/<grp_id>/type" file could be read to find out the
default domain type of an iommu group. The default domain of an iommu group
doesn't change after booting and hence could be read directly. But,
after addding support to dynamically change iommu group default domain, the
above assumption no longer stays valid.

iommu group default domain type could be changed at any time by writing to
"/sys/kernel/iommu_groups/<grp_id>/type". So, take group mutex before
reading iommu group default domain type so that the user wouldn't see stale
values or iommu_group_show_type() doesn't try to derefernce stale pointers.
Signed-off-by: NSai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: NLu Baolu <baolu.lu@linux.intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Link: https://lore.kernel.org/r/20201124130604.2912899-4-baolu.lu@linux.intel.comSigned-off-by: NWill Deacon <will@kernel.org>

Presently, the default domain of an iommu group is allocated during boot
time and it cannot be changed later. So, the device would typically be
either in identity (also known as pass_through) mode or the device would be
in DMA mode as long as the machine is up and running. There is no way to
change the default domain type dynamically i.e. after booting, a device
cannot switch between identity mode and DMA mode.

But, assume a use case wherein the user trusts the device and believes that
the OS is secure enough and hence wants *only* this device to bypass IOMMU
(so that it could be high performing) whereas all the other devices to go
through IOMMU (so that the system is protected). Presently, this use case
is not supported. It will be helpful if there is some way to change the
default domain of an iommu group dynamically. Hence, add such support.

A privileged user could request the kernel to change the default domain
type of a iommu group by writing to
"/sys/kernel/iommu_groups/<grp_id>/type" file. Presently, only three values
are supported
1. identity: all the DMA transactions from the device in this group are
             *not* translated by the iommu
2. DMA: all the DMA transactions from the device in this group are
        translated by the iommu
3. auto: change to the type the device was booted with

Note:
1. Default domain of an iommu group with two or more devices cannot be
   changed.
2. The device in the iommu group shouldn't be bound to any driver.
3. The device shouldn't be assigned to user for direct access.
4. The change request will fail if any device in the group has a mandatory
   default domain type and the requested one conflicts with that.

Please see "Documentation/ABI/testing/sysfs-kernel-iommu_groups" for more
information.
Signed-off-by: NSai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: NLu Baolu <baolu.lu@linux.intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Link: https://lore.kernel.org/r/20201124130604.2912899-3-baolu.lu@linux.intel.comSigned-off-by: NWill Deacon <will@kernel.org>