Hi All, Answering my own question :) :
I have run the demo from https://github.com/siemens/jailhouse-images for Raspberry Pie and simply collected the output of "cat /proc/iomem" before running Jailhouse, then after enabling Jailhouse in the root cell and in a Linux non-root cell. From that output it looks like Jialhouse does 1:1 mapping between IPAs and PAs. On a platform with Zynq UltraScale+ MPSoC, onto which Jailhouse has been ported, I have experimented with memory accesses, trying to access from the root cell the memory allocated to a non-root Linux cell and the other way round - trying to access from the non-root Linux cell the memory allocated to the root cell only. As expected, in both cases I have got "Unhandled data write...FATAL: unhandled trap (exception class 0x24)", while the cells can happily read from/write into physical addresses belonging to their own memory regions specified in the respective cells configuration. This appears to confirm the use of the 2nd stage translations for restricting cells access to physical memory. Best Regards, Yelena On Monday, November 14, 2022 at 2:19:55 PM UTC Yelena Konyukh wrote: > Hi All, > > I would be very grateful, if anyone could explain how Jailhouse on ARM64 > architectures uses the 2nd stage MMU translation. > > It does look like Jailhouse uses the 2nd stage MMU translations - for > example, t is easy to find in the code where such registers as VTCR_EL2 > and VTTBR_EL2 are set. I am guessing that Jailhouse, as one would expect > from a hypervisor, uses 2nd stage translation to protect VMs (cells) from > accessing each others memory (unless a memory region is explicitly shared > with a root cell by specifying JAILHOUSE_MEM_ROOTSHARED). Is that so? > Could anyone confirm? How is IPA<->PA mapping is done for VMs? Is it 1-to-1 > mapping (so that, in fact, PA equals IPA)? > > Thank you very much in advance > > Best Regards, > > Yelena > -- You received this message because you are subscribed to the Google Groups "Jailhouse" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/jailhouse-dev/06ab8036-e7b6-458b-990e-2f685b5fc857n%40googlegroups.com.
