This patch supports the upcomming Intel IOMMU hardware a.k.a. Intel(R)
Virtualization Technology for Directed I/O Architecture and the hardware spec
for the same can be found here
http://www.intel.com/technology/virtualization/index.htm
FAQ! (questions from akpm, answers from ak)
> So... what's all this code for?
>
> I assume that the intent here is to speed things up under Xen, etc?
Yes in some cases, but not this code. That would be the Xen version of this
code that could potentially assign whole devices to guests. I expect this to
be only useful in some special cases though because most hardware is not
virtualizable and you typically want an own instance for each guest.
Ok at some point KVM might implement this too; i likely would use this code
for this.
> Do we
> have any benchmark results to help us to decide whether a merge would be
> justified?
The main advantage for doing it in the normal kernel is not performance, but
more safety. Broken devices won't be able to corrupt memory by doing random
DMA.
Unfortunately that doesn't work for graphics yet, for that need user space
interfaces for the X server are needed.
There are some potential performance benefits too:
- When you have a device that cannot address the complete address range an
IOMMU can remap its memory instead of bounce buffering. Remapping is likely
cheaper than copying.
- The IOMMU can merge sg lists into a single virtual block. This could
potentially speed up SG IO when the device is slow walking SG lists. [I
long ago benchmarked 5% on some block benchmark with an old MPT Fusion; but
it probably depends a lot on the HBA]
And you get better driver debugging because unexpected memory accesses from
the devices will cause a trappable event.
>
> Does it slow anything down?
It adds more overhead to each IO so yes.
This patch:
Add support for early detection and parsing of DMAR's (DMA Remapping) reported
to OS via ACPI tables.
DMA remapping(DMAR) devices support enables independent address translations
for Direct Memory Access(DMA) from Devices. These DMA remapping devices are
reported via ACPI tables and includes pci device scope covered by these DMA
remapping device.
For detailed info on the specification of "Intel(R) Virtualization Technology
for Directed I/O Architecture" please see
http://www.intel.com/technology/virtualization/index.htm
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Muli Ben-Yehuda <muli@il.ibm.com>
Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Greg KH <greg@kroah.com>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Added 2007 copyright to all module headers and signons. This affects
virtually every file in the ACPICA core subsystem, iASL compiler,
and the utilities.
Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Implement support for ACPI DMAR table (DMA
Remapping Table) in header files and disassembler.
Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
The Table Manager component has been completely
redesigned and reimplemented. The new design is much
simpler, and reduces the overall code and data size of
the kernel-resident ACPICA by approximately 5%. Also,
it is now possible to obtain the ACPI tables very early
during kernel initialization, even before dynamic memory
management is initialized.
Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Implemented header file support for the following
additional ACPI tables: ASF!, BOOT, CPEP, DBGP, MCFG, SPCR,
SPMI, TCPA, and WDRT. With this support, all current and
known ACPI tables are now defined in the ACPICA headers and
are available for use by device drivers and other software.
Implemented support to allow tables that contain ACPI
names with invalid characters to be loaded. Previously,
this would cause the table load to fail, but since
there are several known cases of such tables on
existing machines, this change was made to enable
ACPI support for them. Also, this matches the
behavior of the Microsoft ACPI implementation.
https://bugzilla.novell.com/show_bug.cgi?id=147621
Fixed a couple regressions introduced during the memory
optimization in the 20060317 release. The namespace
node definition required additional reorganization and
an internal datatype that had been changed to 8-bit was
restored to 32-bit. (Valery Podrezov)
Fixed a problem where a null pointer passed to
acpi_ut_delete_generic_state() could be passed through
to acpi_os_release_object which is unexpected. Such
null pointers are now trapped and ignored, matching
the behavior of the previous implementation before the
deployment of acpi_os_release_object(). (Valery Podrezov,
Fiodor Suietov)
Fixed a memory mapping leak during the deletion of
a SystemMemory operation region where a cached memory
mapping was not deleted. This became a noticeable problem
for operation regions that are defined within frequently
used control methods. (Dana Meyers)
Reorganized the ACPI table header files into two main
files: one for the ACPI tables consumed by the ACPICA core,
and another for the miscellaneous ACPI tables that are
consumed by the drivers and other software. The various
FADT definitions were merged into one common section and
three different tables (ACPI 1.0, 1.0+, and 2.0)
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Added 2006 copyright.
At SuSE's suggestion, enabled all error messages
without enabling function tracing, ie with CONFIG_ACPI_DEBUG=n
Replaced all instances of the ACPI_DEBUG_PRINT macro invoked at
the ACPI_DB_ERROR and ACPI_DB_WARN debug levels with
the ACPI_REPORT_ERROR and ACPI_REPORT_WARNING macros,
respectively. This preserves all error and warning messages
in the non-debug version of the ACPICA code (this has been
referred to as the "debug lite" option.) Over 200 cases
were converted to create a total of over 380 error/warning
messages across the ACPICA code. This increases the code
and data size of the default non-debug version by about 13K.
Added ACPI_NO_ERROR_MESSAGES flag to enable deleting all messages.
The size of the debug version remains about the same.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
The use of the CPU stack in the debug version of the
subsystem has been considerably reduced. Previously, a
debug structure was declared in every function that used
the debug macros. This structure has been removed in
favor of declaring the individual elements as parameters
to the debug functions. This reduces the cumulative stack
use during nested execution of ACPI function calls at the
cost of a small increase in the code size of the debug
version of the subsystem. With assistance from Alexey
Starikovskiy and Len Brown.
Added the ACPI_GET_FUNCTION_NAME macro to enable the
compiler-dependent headers to define a macro that will
return the current function name at runtime (such as
__FUNCTION__ or _func_, etc.) The function name is used
by the debug trace output. If ACPI_GET_FUNCTION_NAME
is not defined in the compiler-dependent header, the
function name is saved on the CPU stack (one pointer per
function.) This mechanism is used because apparently there
exists no standard ANSI-C defined macro that that returns
the function name.
Alexey Starikovskiy redesigned and reimplemented the
"Owner ID" mechanism used to track namespace objects
created/deleted by ACPI tables and control method
execution. A bitmap is now used to allocate and free the
IDs, thus solving the wraparound problem present in the
previous implementation. The size of the namespace node
descriptor was reduced by 2 bytes as a result.
Removed the UINT32_BIT and UINT16_BIT types that were used
for the bitfield flag definitions within the headers for
the predefined ACPI tables. These have been replaced by
UINT8_BIT in order to increase the code portability of
the subsystem. If the use of UINT8 remains a problem,
we may be forced to eliminate bitfields entirely because
of a lack of portability.
Alexey Starikovksiy enhanced the performance of
acpi_ut_update_object_reference. This is a frequently used
function and this improvement increases the performance
of the entire subsystem.
Alexey Starikovskiy fixed several possible memory leaks
and the inverse - premature object deletion.
Signed-off-by: Len Brown <len.brown@intel.com>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
