Re: smmuv1 breakage

[Rahul Singh <Rahul.Singh@xxxxxxx>]

Hi Stefano

> On 15 Jun 2021, at 3:21 am, Stefano Stabellini <sstabellini@xxxxxxxxxx> wrote:
> 
> Hi Rahul,
> 
> Unfortunately, after bisecting, I discovered a few more breakages due to
> your smmuv1 series (commits e889809b .. 3e6047ddf) on Xilinx ZynqMP. I
> attached the DTB as reference. Please note that I made sure to
> cherry-pick "xen/arm: smmuv1: Revert associating the group pointer with
> the S2CR" during bisection. So the errors are present also on staging.
> 
> The first breakage is an error at boot time in smmu.c#find_smmu_master,
> see log1. I think it is due to the lack of ability to parse the new smmu
> bindings in the old smmu driver.
> 
> After removing all the "smmus" and "#stream-id-cells" properties in
> device tree, I get past the previous error, everything seems to be OK at
> early boot, but I actually get SMMU errors as soon as dom0 starting
> using devices:
> 
> (XEN) smmu: /smmu@fd800000: Unexpected global fault, this could be serious
> (XEN) smmu: /smmu@fd800000:     GFSR 0x80000002, GFSYNR0 0x00000000, GFSYNR1 
> 0x00000877, GFSYNR2 0x00000000

 This fault is "Unidentified stream fault” for StreamID “ 0x877” that means 
SMMU SMR is not configured for streamID “0x877"


> [   10.419681] macb ff0e0000.ethernet eth0: DMA bus error: HRESP not OK
> [   10.426452] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
> 
> Do you think you'll be able to help fix them?
> 
> 
> You should be able to reproduce the two issues using Xilinx QEMU (but to
> be honest I haven't tested it on QEMU yet, I was testing on real
> hardware):
> - clone and compile xilinx QEMU https://github.com/Xilinx/qemu.git
>  ./configure  --target-list=aarch64-softmmu
>  make
> - clone and build git://github.com/Xilinx/qemu-devicetrees.git
> - use the attached script to run it
>    - kernel can be upstream defconfig 5.10
> 

I tried to reproduce the issue on Xilinx QEMU as per the steps shared above 
but I am not observing any issue on Xilinx QEMU.

I also tested and confirmed on QEMU that SMMU is configured correctly 
for specifically StreamID “ 0x877” and for other streamIDs.

I check the xen.dtb shared by you and found out the there is no 
"stream-id-cells”
property in the master device but the "mmu-masters" property is present in the
smmu node. For legacy smmu binding we need both "stream-id-cells” and 
"mmu-masters”.
If you need to add the new smmu binding please add the "iommu-cells”
property in the smmu node and the “iommus” property in the master device.

Can you please share the xen boot logs with me so that I can debug further why 
the error is observed? 

Regards,
Rahul


> Cheers,
> 
> Stefano<xen.dtb><log1.txt><qemu-run-zynqmp-xilinx-xen.sh>