On 03/08/17 16:45, Nate Watterson wrote: > Hi Lorenzo, > > On 8/3/2017 8:32 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/[email protected] >> v1: >> http://lkml.kernel.org/r/[email protected] >> >> -- Original cover letter -- >> >> As reported in: >> >> http://lkml.kernel.org/r/cal85gma_sscwm80tkdkzqee+s1bewzdevdki1kpkmutdrms...@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 <[email protected]> >> Cc: Hanjun Guo <[email protected]> >> Cc: Feng Kan <[email protected]> >> Cc: Jon Masters <[email protected]> >> Cc: Robert Moore <[email protected]> >> Cc: Robin Murphy <[email protected]> >> Cc: Zhang Rui <[email protected]> >> Cc: "Rafael J. Wysocki" <[email protected]> >> >> 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(-) >> > > I tested with named components and with _DMA objects at a variety of > sizes and verified the configured masks matched the expected values. > > Tested-by: Nate Watterson <[email protected]> > > One general question I had while testing the patch is whether it is > possible to define a complete 64-bit range using the _DMA method. For > instance, to get a 64-bit dma_mask I had to use a non-zero MIN value > so that LEN would not overflow.
As far as I understand ACPI, all addresses are at most 64-bit. Thus the only valid DMA range of size 2^64 would be one with a minimum of 0 and no offset, and that can already be described by the simple absence of a _DMA object. Robin. > > QWORDMemory( > ResourceConsumer, > PosDecode, // _DEC > MinFixed, // _MIF > MaxFixed, // _MAF > Prefetchable, // _MEM > ReadWrite, // _RW > 0, // _GRA > 0x1000, // _MIN > 0xffffffffffffffff, // _MAX > 0x0, // _TRA > 0xfffffffffffff000, // _LEN > , > , > , > ) > > -Nate >
