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

[Andrii Anisov <Andrii_Anisov@xxxxxxxx>]

+xen-devel

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. 

[1] 
https://elixir.bootlin.com/linux/v5.1/source/arch/arm/mach-omap2/omap-headsmp.S#L62

ANDRII ANISOV

Lead Systems Engineer

 

Office: +380 44 390 5457 x 66766   Cell: +380 50 573 8852   Email: 
andrii_anisov@xxxxxxxx

Kyiv, Ukraine (GMT+3)   epam.com

 

CONFIDENTIALITY CAUTION AND DISCLAIMER
This message is intended only for the use of the individual(s) or entity(ies) 
to which it is addressed and contains information that is legally privileged 
and confidential. If you are not the intended recipient, or the person 
responsible for delivering the message to the intended recipient, you are 
hereby notified that any dissemination, distribution or copying of this 
communication is strictly prohibited. All unintended recipients are obliged to 
delete this message and destroy any printed copies.


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel