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2007-10-23m68knommu: add config support for Savant/Rosie1 boardWilson Callan
Add configure support for the Savant/Rosie1 board. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-23m68knommu: updated defconfigGreg Ungerer
Updated defconfig with new options for m68knommu. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-23m68knommu: fix syscall tracingMatt Waddel
Fix the system call code for handling syscall tracing, so strace and gdbserver work properly. This fix originally developed by Philippe De Muyter and Stuart Hughes. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-23Merge branch 'for-2.6.24' of ↵Paul Mackerras
master.kernel.org:/pub/scm/linux/kernel/git/jwboyer/powerpc-4xx into merge
2007-10-23sparc64: zero out dma_lengthFUJITA Tomonori
zero out dma_length in the entry immediately following the last mapped entry for unmap_sg. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-10-23mips: sg_page() falloutJens Axboe
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-10-23alpha: sg_virt() falloutJens Axboe
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-10-23[AVR32] ARRAY_SIZE() cleanupAlejandro Martinez Ruiz
Signed-off-by: Alejandro Martinez Ruiz <alex@flawedcode.org> Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-10-23[AVR32] Implement at32_add_device_cf()Haavard Skinnemoen
Implement at32_add_device_cf() which will add a platform_device for the at32_cf driver (not merged yet). Separate out most of the at32_add_device_ide() code and use it to implement at32_add_device_cf() as well. This changes the API in the following ways: * The board code must initialize data->cs to the chipselect ID to use before calling any of these functions. * The board code must use GPIO_PIN_NONE to indicate unused CF pins. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-10-23[AVR32] Implement more at32_add_device_foo() functionsHaavard Skinnemoen
Implement functions for adding platform devices for TWI, MCI, AC97C and ABDAC. They may need to be modified to cope with platform data, etc. when the corresponding drivers are ready to be merged, but such changes are much less likely to conflict than adding support for a whole new type of device. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-10-23[AVR32] Fix a couple of sparse warningsHaavard Skinnemoen
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-10-23[AVR32] Wire up AT73C213 sound driver on ATSTK1000 boardHans-Christian Egtvedt
Signed-off-by: Hans-Christian Egtvedt <hcegtvedt@atmel.com> Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-10-23[AVR32] Platform code for pata_at32Kristoffer Nyborg Gregertsen
This patch adds platform code for PATA devices on the AP7000. [hskinnemoen@atmel.com: board code left out for now since stk1000 doesn't support IDE out of the box] Signed-off-by: Kristoffer Nyborg Gregertsen <kngregertsen@norway.atmel.com> Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-10-23parisc: fix sg_page() falloutFUJITA Tomonori
arch/parisc/kernel/pci-dma.c: In function 'pa11_dma_map_sg': arch/parisc/kernel/pci-dma.c:487: error: 'struct scatterlist' has no member named 'page' arch/parisc/kernel/pci-dma.c: In function 'pa11_dma_unmap_sg': arch/parisc/kernel/pci-dma.c:508: error: 'struct scatterlist' has no member named 'page' arch/parisc/kernel/pci-dma.c:508: error: 'struct scatterlist' has no member named 'page' arch/parisc/kernel/pci-dma.c: In function 'pa11_dma_sync_sg_for_cpu': arch/parisc/kernel/pci-dma.c:535: error: 'struct scatterlist' has no member named 'page' arch/parisc/kernel/pci-dma.c:535: error: 'struct scatterlist' has no member named 'page' arch/parisc/kernel/pci-dma.c: In function 'pa11_dma_sync_sg_for_device': arch/parisc/kernel/pci-dma.c:545: error: 'struct scatterlist' has no member named 'page' arch/parisc/kernel/pci-dma.c:545: error: 'struct scatterlist' has no member named 'page' Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-10-23arm: build fixFUJITA Tomonori
arch/arm/common/dmabounce.c: In function 'dma_map_sg': arch/arm/common/dmabounce.c:445: error: implicit declaration of function 'sg_page' Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-10-23Revert lguest magic and use hook in head.SRusty Russell
Version 2.07 of the boot protocol uses 0x23C for the hardware_subarch field, that for lguest is "1". This allows us to use the standard boot entry point rather than the "GenuineLguest" string hack. The standard entry point also clears the BSS and copies the boot parameters and commandline for us, saving more code. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23Lguest support for VirtioRusty Russell
This makes lguest able to use the virtio devices. We change the device descriptor page from a simple array to a variable length "type, config_len, status, config data..." format, and implement virtio_config_ops to read from that config data. We use the virtio ring implementation for an efficient Guest <-> Host virtqueue mechanism, and the new LHCALL_NOTIFY hypercall to kick the host when it changes. We also use LHCALL_NOTIFY on kernel addresses for very very early console output. We could have another hypercall, but this hack works quite well. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23Remove old lguest bus and drivers.Rusty Russell
This gets rid of the lguest bus, drivers and DMA mechanism, to make way for a generic virtio mechanism. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23Virtio helper routines for a descriptor ringbuffer implementationRusty Russell
These helper routines supply most of the virtqueue_ops for hypervisors which want to use a ring for virtio. Unlike the previous lguest implementation: 1) The rings are variable sized (2^n-1 elements). 2) They have an unfortunate limit of 65535 bytes per sg element. 3) The page numbers are always 64 bit (PAE anyone?) 4) They no longer place used[] on a separate page, just a separate cacheline. 5) We do a modulo on a variable. We could be tricky if we cared. 6) Interrupts and notifies are suppressed using flags within the rings. Users need only get the ring pages and provide a notify hook (KVM wants the guest to allocate the rings, lguest does it sanely). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Dor Laor <dor.laor@qumranet.com>
2007-10-23Boot with virtual == physical to get closer to native Linux.Rusty Russell
1) This allows us to get alot closer to booting bzImages. 2) It means we don't have to know page_offset. 3) The Guest needs to modify the boot pagetables to create the PAGE_OFFSET mapping before jumping to C code. 4) guest_pa() walks the page tables rather than using page_offset. 5) We don't use page_offset to figure out whether to emulate: it was always kinda quesationable, and won't work for instructions done before remapping (bzImage unpacking in particular). 6) We still want the kernel address for tlb flushing: have the initial hypercall give us that, too. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23Allow guest to specify syscall vector to use.Rusty Russell
(Based on Ron Minnich's LGUEST_PLAN9_SYSCALL patch). This patch allows Guests to specify what system call vector they want, and we try to reserve it. We only allow one non-Linux system call vector, to try to avoid DoS on the Host. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23Make hypercalls arch-independent.Jes Sorensen
Clean up the hypercall code to make the code in hypercalls.c architecture independent. First process the common hypercalls and then call lguest_arch_do_hcall() if the call hasn't been handled. Rename struct hcall_ring to hcall_args. This patch requires the previous patch which reorganize the layout of struct lguest_regs on i386 so they match the layout of struct hcall_args. Signed-off-by: Jes Sorensen <jes@sgi.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23Move i386 part of core.c to x86/core.c.Jes Sorensen
Separate i386 architecture specific from core.c and move it to x86/core.c and add x86/lguest.h header file to match. Signed-off-by: Jes Sorensen <jes@sgi.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23Move lguest guest support to arch/x86.Rusty Russell
Lguest has two sides: host support (to launch guests) and guest support (replacement boot path and paravirt_ops). This moves the guest side to arch/x86/lguest where it's closer to related code. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <ak@suse.de>
2007-10-23Normalize config options for guest supportRusty Russell
1) Group all the "guest OS" support options together, under a PARAVIRT_GUEST menu. 2) Make those options select CONFIG_PARAVIRT, as suggested by Andi. 3) Make kconfig help titles consistent. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <ak@suse.de> Cc: Zach Amsden <zach@vmware.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Chris Wright <chrisw@sous-sol.org>
2007-10-22Merge branch 'for-linus' of ↵Linus Torvalds
master.kernel.org:/pub/scm/linux/kernel/git/cooloney/blackfin-2.6 * 'for-linus' of master.kernel.org:/pub/scm/linux/kernel/git/cooloney/blackfin-2.6: Blackfin arch: use KBUILD_CFLAGS and KBUILD_AFLAGS in Makefile Blackfin arch: Javier Herrer writes: fix building when icache and dcache is disabled
2007-10-22Merge branch 'for-linus' of git://git390.osdl.marist.edu/pub/scm/linux-2.6Linus Torvalds
* 'for-linus' of git://git390.osdl.marist.edu/pub/scm/linux-2.6: [S390] 4level-fixup cleanup [S390] Cleanup page table definitions. [S390] Introduce follow_table in uaccess_pt.c [S390] Remove unused user_seg from thread structure. [S390] tlb flush fix. [S390] kernel: Fix dump on panic for DASDs under LPAR. [S390] struct class_device -> struct device conversion. [S390] cio: Fix incomplete commit for uevent suppression. [S390] cio: Use to_channelpath() for device to channel path conversion. [S390] Add per-cpu idle time / idle count sysfs attributes. [S390] Update default configuration.
2007-10-22Merge branch 'master' of ↵Linus Torvalds
master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6 * 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6: [SPARC64]: ARRAY_SIZE() cleanup [SPARC64]: small Makefile cleanups [SPARC64]: Stop using __do_IRQ(). [SPARC64]: Update defconfig.
2007-10-22Merge branch 'master' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc * 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc: [POWERPC] Enable restart support for lite5200 board [POWERPC] Add restart support for mpc52xx based platforms [POWERPC] Update device tree binding for mpc5200 gpt [POWERPC] Add mpc52xx_find_and_map_path(), refactor utility functions [POWERPC] bestcomm: Restrict bus prefetch bugfix to original mpc5200 silicon.
2007-10-22Merge branch 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linusLinus Torvalds
* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus: [MIPS] time: Make c0_compare_int_usable more bullet proof [MIPS] Kbuild: Use the new cc-cross-prefix feature. [MIPS] Fix include wrapper symbol to something sane. [MIPS] Malta: Delete dead code. [MIPS] time: Add GT641xx timer0 clockevent driver [MIPS] time: SMP-proofing of Sibyte clockevent/clocksource code. [MIPS] time: SMP/NUMA-proofing of IP27 HUB RT timer code. [MIPS] time: Fix calculation in clockevent_set_clock()
2007-10-22Merge branch 'sg' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'sg' of git://git.kernel.dk/linux-2.6-block: Add CONFIG_DEBUG_SG sg validation Change table chaining layout Update arch/ to use sg helpers Update swiotlb to use sg helpers Update net/ to use sg helpers Update fs/ to use sg helpers [SG] Update drivers to use sg helpers [SG] Update crypto/ to sg helpers [SG] Update block layer to use sg helpers [SG] Add helpers for manipulating SG entries
2007-10-22[SPARC64]: ARRAY_SIZE() cleanupAlejandro Martinez Ruiz
Signed-off-by: Alejandro Martinez Ruiz <alex@flawedcode.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-23Merge branch 'for-2.6.24' of git://git.secretlab.ca/git/linux-2.6-mpc52xxPaul Mackerras
2007-10-22[MIPS] time: Make c0_compare_int_usable more bullet proofAtsushi Nemoto
Use write_c0_compare(read_c0_count()) to clear interrupt. Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-22[MIPS] Kbuild: Use the new cc-cross-prefix feature.Ralf Baechle
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-22[MIPS] Malta: Delete dead code.Ralf Baechle
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-22[MIPS] time: Add GT641xx timer0 clockevent driverYoichi Yuasa
And make use of it for Cobalt. A few others such as the Malta could make use of it as well. Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-22[MIPS] time: SMP-proofing of Sibyte clockevent/clocksource code.Ralf Baechle
The BCM148 has 4 cores but there are also just 4 generic timers available so use the ZBbus cycle counter instead of it. In addition the ZBbus counter also offers a much higher resolution and 64-bit counting so I'm considering a later complete conversion to it once I figure out if all members of the Sibyte SOC family support it - the docs seem to agree but the headers files seem to disagree ... Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-22[MIPS] time: SMP/NUMA-proofing of IP27 HUB RT timer code.Ralf Baechle
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-22[MIPS] time: Fix calculation in clockevent_set_clock()Atsushi Nemoto
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-22[CPUFREQ] architectural pstate driver for powernow-k8Mark Langsdorf
This patch should apply cleanly to the 2.6.23-git7 kernel.  It changes the powernow-k8 driver code that deals with 3rd generation Opteron, Phenom, and later processors to match the architectural pstate driver described in the AMD64 Architecture Programmer's Manual Volume 2 Chapter 18.  The initial implementation of the hardware pstate driver for PowerNow! used some processor-version specific features, and would not be maintainable in the long term as the processor features changed. This architectural driver should work on all future AMD processors.   Signed-off-by: Mark Langsdorf <mark.langsdorf@amd.com> Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Dave Jones <davej@redhat.com>
2007-10-22Update arch/ to use sg helpersJens Axboe
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-10-22[SG] Update drivers to use sg helpersJens Axboe
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-10-22kexec: add BSS to resource treeBernhard Walle
Add the BSS to the resource tree just as kernel text and kernel data are in the resource tree. The main reason behind this is to avoid crashkernel reservation in that area. While it's not strictly necessary to have the BSS in the resource tree (the actual collision detection is done in the reserve_bootmem() function before), the usage of the BSS resource should be presented to the user in /proc/iomem just as Kernel data and Kernel code. Note: The patch currently is only implemented for x86 and ia64 (because efi_initialize_iomem_resources() has the same signature on i386 and ia64). [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Bernhard Walle <bwalle@suse.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@in.ibm.com> Cc: <linux-arch@vger.kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-22Intel IOMMU: Iommu floppy workaroundKeshavamurthy, Anil S
This config option (DMAR_FLPY_WA) sets up 1:1 mapping for the floppy device so that the floppy device which does not use DMA api's will continue to work. Once the floppy driver starts using DMA api's this config option can be turn off or this patch can be yanked out of kernel at that time. [akpm@linux-foundation.org: cleanups, rename things, build fix] [jengelh@computergmbh.de: Kconfig fixes] 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> Signed-off-by: Jan Engelhardt <jengelh@gmx.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-22Intel IOMMU: Iommu Gfx workaroundKeshavamurthy, Anil S
When we fix all the opensource gfx drivers to use the DMA api's, at that time we can yank this config options out. [jengelh@computergmbh.de: Kconfig fixes] 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> Signed-off-by: Jan Engelhardt <jengelh@gmx.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-22Intel IOMMU: DMAR fault handling supportKeshavamurthy, Anil S
MSI interrupt handler registrations and fault handling support for Intel-IOMMU hadrware. This patch enables the MSI interrupts for the DMA remapping units and in the interrupt handler read the fault cause and outputs the same on to the console. 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-22Intel IOMMU: Intel IOMMU driverKeshavamurthy, Anil S
Actual intel IOMMU driver. Hardware spec can be found at: http://www.intel.com/technology/virtualization This driver sets X86_64 'dma_ops', so hook into standard DMA APIs. In this way, PCI driver will get virtual DMA address. This change is transparent to PCI drivers. [akpm@linux-foundation.org: remove unneeded cast] [akpm@linux-foundation.org: build fix] [bunk@stusta.de: fix duplicate CONFIG_DMAR Makefile line] 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> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-22Intel IOMMU: clflush_cache_range now takes size paramKeshavamurthy, Anil S
Introduce the size param for clflush_cache_range(). 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: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-22Intel IOMMU: DMAR detection and parsing logicKeshavamurthy, Anil S
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>