Messages in this thread | | | Subject | Re: [PATCH 2/2] arm64: dts: juno: Enable more SMMUs | From | Robin Murphy <> | Date | Fri, 30 Jul 2021 15:44:07 +0100 |
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On 2021-07-30 15:34, Anders Roxell wrote: > On 2021-07-30 13:17, Robin Murphy wrote: >> On 2021-07-30 12:35, Anders Roxell wrote: >>> From: Robin Murphy <robin.murphy@arm.com> >>> >>>> Now that PCI inbound window restrictions are handled generically between >>>> the of_pci resource parsing and the IOMMU layer, and described in the >>>> Juno DT, we can finally enable the PCIe SMMU without the risk of DMA >>>> mappings inadvertently allocating unusable addresses. >>>> >>>> Similarly, the relevant support for IOMMU mappings for peripheral >>>> transfers has been hooked up in the pl330 driver for ages, so we can >>>> happily enable the DMA SMMU without that breaking anything either. >>>> >>>> Signed-off-by: Robin Murphy <robin.murphy@arm.com> >>> >>> When we build a kernel with 64k page size and run the ltp syscalls we >>> sporadically see a kernel crash while doing a mkfs on a connected SATA >>> drive. This is happening every third test run on any juno-r2 device in >>> the lab with the same kernel image (stable-rc 5.13.y, mainline and next) >>> with gcc-11. >> >> Hmm, I guess 64K pages might make a difference in that we'll chew through >> IOVA space a lot faster with small mappings... >> >> I'll have to try to reproduce this locally, since the interesting thing >> would be knowing what DMA address it was trying to use that went wrong, but >> IOMMU tracepoints and/or dma-debug are going to generate an crazy amount of >> data to sift through and try to correlate - having done it before it's not >> something I'd readily ask someone else to do for me :) >> >> On a hunch, though, does it make any difference if you remove the first >> entry from the PCIe "dma-ranges" (the 0x2c1c0000 one)? > > I did this change, and run the job 7 times and could not reproduce the > issue.
Thanks! And hold that thought; if it works then I suspect it probably is the best fix, but I'll double-check and write it up properly next week.
Cheers, Robin.
> diff --git a/arch/arm64/boot/dts/arm/juno-base.dtsi b/arch/arm64/boot/dts/arm/juno-base.dtsi > index 8e7a66943b01..d3148730e951 100644 > --- a/arch/arm64/boot/dts/arm/juno-base.dtsi > +++ b/arch/arm64/boot/dts/arm/juno-base.dtsi > @@ -545,8 +545,7 @@ pcie_ctlr: pcie@40000000 { > <0x02000000 0x00 0x50000000 0x00 0x50000000 0x0 0x08000000>, > <0x42000000 0x40 0x00000000 0x40 0x00000000 0x1 0x00000000>; > /* Standard AXI Translation entries as programmed by EDK2 */ > - dma-ranges = <0x02000000 0x0 0x2c1c0000 0x0 0x2c1c0000 0x0 0x00040000>, > - <0x02000000 0x0 0x80000000 0x0 0x80000000 0x0 0x80000000>, > + dma-ranges = <0x02000000 0x0 0x80000000 0x0 0x80000000 0x0 0x80000000>, > <0x43000000 0x8 0x00000000 0x8 0x00000000 0x2 0x00000000>; > #interrupt-cells = <1>; > interrupt-map-mask = <0 0 0 7>; > > > Cheers, > Anders >
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