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The userspace can request an arbitrary supported page size for a DMA
window and this works fine as long as the mapped memory is backed with
the pages of the same or bigger size; if this is not the case,
mm_iommu_ua_to_hpa{_rm}() fail and tables do not populated with
dangerously incorrect TCEs.
However since it is quite easy to misconfigure the KVM and we do not do
reverts to all changes made to TCE tables if an error happens in a middle,
we better do the acceptable page size validation before we even touch
the tables.
This enhances kvmppc_tce_validate() to check the hardware IOMMU page sizes
against the preregistered memory page sizes.
Since the new check uses real/virtual mode helpers, this renames
kvmppc_tce_validate() to kvmppc_rm_tce_validate() to handle the real mode
case and mirrors it for the virtual mode under the old name. The real
mode handler is not used for the virtual mode as:
1. it uses _lockless() list traversing primitives instead of RCU;
2. realmode's mm_iommu_ua_to_hpa_rm() uses vmalloc_to_phys() which
virtual mode does not have to use and since on POWER9+radix only virtual
mode handlers actually work, we do not want to slow down that path even
a bit.
This removes EXPORT_SYMBOL_GPL(kvmppc_tce_validate) as the validators
are static now.
From now on the attempts on mapping IOMMU pages bigger than allowed
will result in KVM exit.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
[mpe: Fix KVM_HV=n build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.