MSI and MSI-X support for interrupt remapping infrastructure.
MSI address register will be programmed with interrupt-remapping table
entry(IRTE) index and the IRTE will contain information about the vector,
cpu destination, etc.
For MSI-X, all the IRTE's will be consecutively allocated in the table,
and the address registers will contain the starting index to the block
and the data register will contain the subindex with in that block.
This also introduces a new irq_chip for cleaner irq migration (in the process
context as opposed to the current irq migration in the context of an interrupt.
interrupt-remapping infrastructure will help us achieve this).
As MSI is edge triggered, irq migration is a simple atomic update(of vector
and cpu destination) of IRTE and flushing the hardware cache.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
IO-APIC support in the presence of interrupt-remapping infrastructure.
IO-APIC RTE will be programmed with interrupt-remapping table entry(IRTE)
index and the IRTE will contain information about the vector, cpu destination,
trigger mode etc, which traditionally was present in the IO-APIC RTE.
Introduce a new irq_chip for cleaner irq migration (in the process
context as opposed to the current irq migration in the context of an interrupt.
interrupt-remapping infrastructure will help us achieve this cleanly).
For edge triggered, irq migration is a simple atomic update(of vector
and cpu destination) of IRTE and flush the hardware cache.
For level triggered, we need to modify the io-apic RTE aswell with the update
vector information, along with modifying IRTE with vector and cpu destination.
So irq migration for level triggered is little bit more complex compared to
edge triggered migration. But the good news is, we use the same algorithm
for level triggered migration as we have today, only difference being,
we now initiate the irq migration from process context instead of the
interrupt context.
In future, when we do a directed EOI (combined with cpu EOI broadcast
suppression) to the IO-APIC, level triggered irq migration will also be
as simple as edge triggered migration and we can do the irq migration
with a simple atomic update to IO-APIC RTE.
TBD: some tests/changes needed in the presence of fixup_irqs() for
level triggered irq migration.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Allocate the iommu during the parse of DMA remapping hardware
definition structures. And also, introduce routines for device
scope initialization which will be explicitly called during
dma-remapping initialization.
These will be used for enabling interrupt remapping separately from the
existing DMA-remapping enabling sequence.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fix an off by one bug in the fault reason string reporting function, and
clean up some of the code around this buglet.
[akpm@linux-foundation.org: cleanup]
Signed-off-by: mark gross <mgross@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
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>
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>
