On 02/03/16 13:56, Shanker Donthineni wrote: > > For some reason v4.5-rc6 kernel is not stable for guest machines on > Qualcomm server platforms. > We are getting IABT translation faults while booting the guest kernel. > The problem disappears with > the following code snippet (insert "dsb ish" instruction just before > switching to EL1 guest). I am > using v4.5-rc6 kernel for both host and guest machines. > > Please let me know if you have any thoughts or ideas for tracing this > problem. > > --- a/arch/arm64/kvm/hyp/entry.S > +++ b/arch/arm64/kvm/hyp/entry.S > @@ -88,6 +88,7 @@ ENTRY(__guest_enter) > ldp x0, x1, [sp], #16 > > // Do not touch any register after this! > + dsb ish > eret > ENDPROC(__guest_enter) > > > Using below QEMU command for launching guest machine: > > qemu-system-aarch64 -machine type=virt,accel=kvm,gic-version=3 \ > -cpu "host" -smp cpus=1,maxcpus=1 -m 256M -serial stdio \ > -kernel /boot/Image -initrd /boot/rootfs.cpio.gz \ > -append 'earlycon=earlycon=pl011,0x09000000 \ > console=ttyAMA0,115200 root=/dev/ram' > > > Guest machine crash log messages: > > [ 0.000000] Booting Linux on physical CPU 0x0 > [ 0.000000] Boot CPU: AArch64 Processor [510f2811] > [ 0.000000] Bad mode in Synchronous Abort handler detected, code > 0x8600000f -- IABT (current EL) > [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.5.rc6+ > [ 0.000000] task: ffffffc000d52200 ti: ffffffc000d44000 task.ti: > ffffffc000d44000 > [ 0.000000] PC is at early_init_dt_scan_root+0x28/0x94 > [ 0.000000] LR is at of_scan_flat_dt+0x9c/0xd0 > [ 0.000000] pc : [<ffffffc000cb32e8>] lr : [<ffffffc000cb3248>] > pstate: 800003c5 > [ 0.000000] sp : ffffffc000d47e80 > [ 0.000000] x29: ffffffc000d47e80 x28: 0000000000000000 > If you're getting a prefetch abort, it would be interesting to find out what instruction is there, whether the page is mapped at stage-2 or not, what are the stage-2 permissions... Basically, a full description of the memory state. Also, does it work if you do a "dsb ishst" instead? Thanks, M. -- Jazz is not dead. It just smells funny... _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
