If we hit this error condition then we want to return a NULL pointer and
not a freed variable.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

As pointed out by Jörg and fixed in commit 11f1a776 ("iommu/vt-d: Check
for NULL pointer in dmar_acpi_dev_scope_init(), this code path can
bizarrely get exercised even on AMD IOMMU systems with IRQ remapping
enabled.

In addition to the defensive check for NULL which Jörg added, let's also
just avoid calling the function at all if there aren't an Intel IOMMU
units in the system.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

When ir_dev_scope_init() is called via a rootfs initcall it
will check for irq_remapping_enabled before it calls
(indirectly) into dmar_acpi_dev_scope_init() which uses the
dmar_tbl pointer without any checks.

The AMD IOMMU driver also sets the irq_remapping_enabled
flag which causes the dmar_acpi_dev_scope_init() function to
be called on systems with AMD IOMMU hardware too, causing a
boot-time kernel crash.
Signed-off-by: Joerg Roedel <joro@8bytes.org>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

It might not be...
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Mostly made redundant by using dev_name() instead of pci_name(), and one
instance of using *dev->dma_mask instead of pdev->dma_mask.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Should hopefully never happen (RMRRs are an abomination) but while we're
busy eliminating all the PCI assumptions, we might as well do it.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Pass the struct device to it, and also make it return the bus/devfn to use,
since that is also stored in the DMAR table.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

It's accessible via info->iommu->segment so this is redundant.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

This was problematic because it works by domain/bus/devfn and we want
to make device_to_iommu() use only a struct device * (for handling non-PCI
devices). Now that the iommu pointer is reliably stored in the
device_domain_info, we don't need to look it up.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Now we store the iommu in the device_domain_info, we don't need to do a
lookup.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

By moving this into get_domain_for_dev() we can make dmar_insert_dev_info()
suitable for use with "special" domains such as the si_domain, which
currently use domain_add_dev_info().
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

It's not only for PCI devices any more, and the scope information for an
ACPI device provides the bus and devfn so that has to be stored here too.

It is the device pointer itself which needs to be protected with RCU,
so the __rcu annotation follows it into the definition of struct
dmar_dev_scope, since we're no longer just passing arrays of device
pointers around.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

In commit 2e12bc29 ("intel-iommu: Default to non-coherent for domains
unattached to iommus") we decided to err on the side of caution and
always assume that it's possible that a device will be attached which is
behind a non-coherent IOMMU.

In some cases, however, that just *cannot* happen. If there *are* no
IOMMUs in the system which are non-coherent, then we don't need to do
it. And flushing the dcache is a *significant* performance hit.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

There is a race condition between the existing clear/free code and the
hardware. The IOMMU is actually permitted to cache the intermediate
levels of the page tables, and doesn't need to walk the table from the
very top of the PGD each time. So the existing back-to-back calls to
dma_pte_clear_range() and dma_pte_free_pagetable() can lead to a
use-after-free where the IOMMU reads from a freed page table.

When freeing page tables we actually need to do the IOTLB flush, with
the 'invalidation hint' bit clear to indicate that it's not just a
leaf-node flush, after unlinking each page table page from the next level
up but before actually freeing it.

So in the rewritten domain_unmap() we just return a list of pages (using
pg->freelist to make a list of them), and then the caller is expected to
do the appropriate IOTLB flush (or tear down the domain completely,
whatever), before finally calling dma_free_pagelist() to free the pages.

As an added bonus, we no longer need to flush the CPU's data cache for
pages which are about to be *removed* from the page table hierarchy anyway,
in the non-cache-coherent case. This drastically improves the performance
of large unmaps.

As a side-effect of all these changes, this also fixes the fact that
intel_iommu_unmap() was neglecting to free the page tables for the range
in question after clearing them.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

We have this horrid API where iommu_unmap() can unmap more than it's asked
to, if the IOVA in question happens to be mapped with a large page.

Instead of propagating this nonsense to the point where we end up returning
the page order from dma_pte_clear_range(), let's just do it once and adjust
the 'size' parameter accordingly.

Augment pfn_to_dma_pte() to return the level at which the PTE was found,
which will also be useful later if we end up changing the API for
iommu_iova_to_phys() to behave the same way as is being discussed upstream.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>