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LS1021A SMMU: bypass configuration and performance issues

Question asked by Vincent Siles on May 3, 2016

Hi !

I'm working on activating the Trustzone Address Controller of my QorIQ LS1021atwr board. Here is

- configure the TZASC correctly (3/4 of the RAM for Linux, 1/4 for the Secure OS)

- configure the different peripheral ICID's

- Flush all SMMU's TLB

- configure all peripheral as "Secure" in the 4 SMMUs

At boot, all SMMUs are bypassed, and I leave them in this configuration.


Doing so, I can correctly boot Linux, however I have two error messages:


udevadm settle - timeout of 3 seconds reached, the event queue contains:
  /sys/devices/soc.2/3100000.usb3/ (1472)
  /sys/devices/soc.2/3100000.usb3/ (1473)
xhci-hcd Timeout while waiting for a slot
hub 2-0:1.0: couldn't allocate port 1 usb_device


2016-03-22 20:42:19.862+0000: 746: info : libvirt version: 1.2.12
2016-03-22 20:42:19.862+0000: 746: warning : virGetHostname:671 : getaddrinfo failed for 'ls1021atwr': Temporary failure in name resolution


I can't test usb right now, but I no longer have access to the network: I don't have any IP address.

I also noticed that user application running on the secure kernel were slowing down the whole board in a really unusual way, as if Linux interrupts were delayed (I can barely enter input on the serial entry). Note that if I only run the kernel on the scure world, no performance drop can be seen, it only happens with userland applications.


If I disable the TZASC, everything goes back to normal.


Does someone have any idea why the ethernet driver no longer finds an IP address, or why the performance are affected that hard ? Maybe I forgot to configure something ?