Messages in this thread | | | Date | Wed, 22 Jun 2022 22:52:25 +0800 | Subject | Re: [PATCH v3] iommu/vt-d: Make DMAR_UNITS_SUPPORTED a config setting | From | Baolu Lu <> |
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On 2022/6/16 02:36, Steve Wahl wrote: > To support up to 64 sockets with 10 DMAR units each (640), make the > value of DMAR_UNITS_SUPPORTED adjustable by a config variable, > CONFIG_DMAR_UNITS_SUPPORTED, and make it's default 1024 when MAXSMP is > set. > > If the available hardware exceeds DMAR_UNITS_SUPPORTED (previously set > to MAX_IO_APICS, or 128), it causes these messages: "DMAR: Failed to > allocate seq_id", "DMAR: Parse DMAR table failure.", and "x2apic: IRQ > remapping doesn't support X2APIC mode x2apic disabled"; and the system > fails to boot properly. > > Signed-off-by: Steve Wahl<steve.wahl@hpe.com> > Reviewed-by: Kevin Tian<kevin.tian@intel.com> > --- > > Note that we could not find a reason for connecting > DMAR_UNITS_SUPPORTED to MAX_IO_APICS as was done previously. Perhaps > it seemed like the two would continue to match on earlier processors. > There doesn't appear to be kernel code that assumes that the value of > one is related to the other. > > v2: Make this value a config option, rather than a fixed constant. The default > values should match previous configuration except in the MAXSMP case. Keeping the > value at a power of two was requested by Kevin Tian. > > v3: Make the config option dependent upon DMAR_TABLE, as it is not used without this. > > drivers/iommu/intel/Kconfig | 7 +++++++ > include/linux/dmar.h | 6 +----- > 2 files changed, 8 insertions(+), 5 deletions(-) > > diff --git a/drivers/iommu/intel/Kconfig b/drivers/iommu/intel/Kconfig > index 39a06d245f12..07aaebcb581d 100644 > --- a/drivers/iommu/intel/Kconfig > +++ b/drivers/iommu/intel/Kconfig > @@ -9,6 +9,13 @@ config DMAR_PERF > config DMAR_DEBUG > bool > > +config DMAR_UNITS_SUPPORTED > + int "Number of DMA Remapping Units supported" > + depends on DMAR_TABLE > + default 1024 if MAXSMP > + default 128 if X86_64 > + default 64
With this patch applied, the IOMMU configuration looks like:
[*] AMD IOMMU support <M> AMD IOMMU Version 2 driver [*] Enable AMD IOMMU internals in DebugFS (1024) Number of DMA Remapping Units supported <<<< NEW [*] Support for Intel IOMMU using DMA Remapping Devices [*] Export Intel IOMMU internals in Debugfs [*] Support for Shared Virtual Memory with Intel IOMMU [*] Enable Intel DMA Remapping Devices by default [*] Enable Intel IOMMU scalable mode by default [*] Support for Interrupt Remapping [*] OMAP IOMMU Support [*] Export OMAP IOMMU internals in DebugFS [*] Rockchip IOMMU Support
The NEW item looks confusing. It looks to be a generic configurable value though it's actually Intel DMAR specific. Any thoughts?
Best regards, baolu
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