ok cool, we'll continue to look into it during the week. Brian Smith wrote: > Andreas, > Thanks for the update. On your suggestion I merged kvmrun into > emulate and got the emulation working with the shadow page tables. I > too got to a point where the guest runs until the first dabt > exception, mine occurs at 0x88 on a load instruction though, but the > storage it's trying to load is the same as what you were showing > (different guest kernel's?). I updated arm_insterrupts.S to save the > fault address register in vcpu->arch.host_far so when it gets to > kvmarm_handle_exit you have the address it was trying to access. I > also added code in kvmarm_handle_exit that attempts to fix the access > then reexecute the instruction. But when the instruction is > reexecuted a dabt exception again occurs and we get in an infinite > loop forever executing the instruction and causing a dabt exception. > I ran out of time to investigate why what I did wasn't sufficient > (search "make_pages_present" in arm.c). On the plus side it's the > user program that is stuck in an infinite loop, the kernel is okay. > > Regards, > Brian > > Andreas Nilsson wrote: >> Brian, >> >> we debugged the boot process today and identified were we get the >> crash. It's in a loop between offsets 0xa0 and 0xb8 in head.S. I've >> described what happens in the wiki and also added pages about MMU >> emulation and moved the boot info to a separate section. Everything >> should be committed to the kvmrun branch. >> >> For the weekend I think there are two main tasks you can look at: >> >> 1. Before we crash we actually encounter some privileged instructions >> which are currently handled as no-ops since we commented out the >> translation/emulation code. It could make sense to try to get to the >> same point where we are now but actually emulate the privileged >> instructions on the way there. It won't solve our crash but it will >> be good testing of the translation/emulation code for the future. >> >> There are actually a whole lot of branches taken which would test the >> block identification and translation pretty well. >> >> 2. Copy the shadow page table code into the emulation branch and play >> around with it to see if you can figure out how to resolve the crash. >> >> GL! >> >> /Andreas >> _______________________________________________ >> Android-virt mailing list >> Android-virt at lists.cs.columbia.edu >> https://lists.cs.columbia.edu/cucslists/listinfo/android-virt >> >> >
