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Re: [Xen-users] Starting to port xen on beagleboard-x15 (GSoC 2019 project)


Hello Julien,

> I am a bit confused. Linux is able to bring-up CPU in hyp mode with the 
> current
> U-boot. Why would we need more changes for Xen?

TI's ROM code starts all CPUs in NS PL1, doesn't matter if it is boot or 
secondary core.
If you look at Linux code [1], you'll see, that after the secondary core 
bringup Linux does switch that core from NS PL1 to PL2 (hyp mode) using ROM 
code interface (smc 0).
At some moment XEN dropped all to-hyp-mode switching code. So I did switch 
secondaries to hyp mode in u-boot with the loop which replicates the ROM Code 
logic in terms of waiting for an event and checking aux registers. 



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