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SubjectRe: [PATCH v3 0/5] ACPI: DMA ranges management
On Wed, Aug 09, 2017 at 04:14:43PM -0500, Jeremy Linton wrote:
> Hi,
>
> Better late than never I guess..
>
> On 08/03/2017 07:32 AM, Lorenzo Pieralisi wrote:
> >This patch series is v3 of a previous posting:
> >
> >v2->v3:
> > - Fixed DMA masks computation
> > - Fixed size computation overflow in acpi_dma_get_range()
> >
> >v1->v2:
> > - Reworked acpi_dma_get_range() flow and logs
> > - Added IORT named component address limits
> > - Renamed acpi_dev_get_resources() helper function
> > - Rebased against v4.13-rc3
> >
> >v2: http://lkml.kernel.org/r/20170731152323.32488-1-lorenzo.pieralisi@arm.com
> >v1: http://lkml.kernel.org/r/20170720144517.32529-1-lorenzo.pieralisi@arm.com
> >
> >-- Original cover letter --
> >
> >As reported in:
> >
> >http://lkml.kernel.org/r/CAL85gmA_SSCwM80TKdkZqEe+S1beWzDEvdki1kpkmUTDRmSP7g@mail.gmail.com
> >
> >the bus connecting devices to an IOMMU bus can be smaller in size than
> >the IOMMU input address bits which results in devices DMA HW bugs in
> >particular related to IOVA allocation (ie chopping of higher address
> >bits owing to system bus HW capabilities mismatch with the IOMMU).
> >
> >Fortunately this problem can be solved through an already present but never
> >used ACPI 6.2 firmware bindings (ie _DMA object) allowing to define the DMA
> >window for a specific bus in ACPI and therefore all upstream devices
> >connected to it.
> >
> >This small patch series enables _DMA parsing in ACPI core code and
> >use it in ACPI IORT code in order to detect DMA ranges for devices and
> >update their data structures to make them work with their related DMA
> >addressing restrictions.
> >
> >Cc: Will Deacon <will.deacon@arm.com>
> >Cc: Hanjun Guo <hanjun.guo@linaro.org>
> >Cc: Feng Kan <fkan@apm.com>
> >Cc: Jon Masters <jcm@redhat.com>
> >Cc: Robert Moore <robert.moore@intel.com>
> >Cc: Robin Murphy <robin.murphy@arm.com>
> >Cc: Zhang Rui <rui.zhang@intel.com>
> >Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> >
> >Lorenzo Pieralisi (5):
> > ACPICA: resource_mgr: Allow _DMA method in walk resources
> > ACPI: Make acpi_dev_get_resources() method agnostic
> > ACPI: Introduce DMA ranges parsing
> > ACPI: Make acpi_dma_configure() DMA regions aware
> > ACPI/IORT: Add IORT named component memory address limits
> >
> > drivers/acpi/acpica/rsxface.c | 7 ++--
> > drivers/acpi/arm64/iort.c | 57 ++++++++++++++++++++++++++-
> > drivers/acpi/resource.c | 82 +++++++++++++++++++++++++++++---------
> > drivers/acpi/scan.c | 91 +++++++++++++++++++++++++++++++++++++++----
> > include/acpi/acnames.h | 1 +
> > include/acpi/acpi_bus.h | 2 +
> > include/linux/acpi.h | 8 ++++
> > include/linux/acpi_iort.h | 5 ++-
> > 8 files changed, 219 insertions(+), 34 deletions(-)
>
> Ok, despite being merged already I think its worthwhile to say that
> I've been testing this with:
>
> Method(_DMA, 0, Serialized)
> {
> Return (ResourceTemplate()
> {
> QWORDMemory(
> ResourceConsumer,

I asked to update the ACPI specifications because this should be
ResourceProducer, we need an errata to sort this out before it
becomes a problem.

> PosDecode, // _DEC
> MinFixed, // _MIF
> MaxFixed, // _MAF
> Prefetchable, // _MEM
> ReadWrite, // _RW
> 0, // _GRA
> 0x10000000, // _MIN
> 0x1fffffff, // _MAX
> 0x000000000, // _TRA
> 0x10000000, // _LEN
> ,
> ,
> ,
> )
> })
> } // Method(_DMA)
>
> (and a couple minor variations)
>
> and a fair number of debug statements sprinkled around to verify
> that the IOVAs are appropriately limited. So I don't see anything
> wrong with the code and it appears to work and the devices behind a
> bridge limited like this continue to work as long as sane values are
> placed in the min/max/len fields.
>
> Thanks,
>
> Tested-by: Jeremy Linton <jeremy.linton@arm.com>

Thank you very much Jeremy for testing it, appreciated please let me
know if you spot anything wrong with it on the machines you are
running tests on.

Lorenzo

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