On 06.06.2011, at 20:38, Scott Wood wrote: > On Sat, 4 Jun 2011 01:59:34 +0200 > Alexander Graf <agraf@xxxxxxx> wrote: > >> >> On 03.06.2011, at 01:15, Scott Wood wrote: >> >>> This patchset contains SPE state management for e500 KVM guests, as well >>> as MMU enhancements (performance, userspace visibility, and support for >>> mapping things that aren't standard kernel-managed pages). >>> >>> They are combined into one patchset because they both touch the >>> MSR update code. >> >> I figured I'd try something new and just applied the whole patch set to see if it actually works. Of course it doesn't :). When I start a guest, it hangs at the point below in guest context and loops at 100%. Trying to dump the registers makes the whole process stall and drop down to 0% cpu usage. Only an external kill helps by then. > > Works for me, with qemu d800040fb47fe4500d1f8bf604b9fd129bda9419 and the > patchset applied to kernel f19ae5734c8d729edee7ad96179b507561541981, same > kernel as guest. Dumping registers works without noticable delay. > >> root@e500:/dev/shm/qemu# ./ppc-softmmu/qemu-system-ppc -nographic -kernel /boot/uImage.autotest -append 'root=/dev/vda3 console=ttyS0 rw' -enable-kvm -m 512 -M mpc8544ds -drive file=/dev/shm/test.qcow2,index=0,if=virtio >> KVM: Couldn't find level irq capability. Expect the VM to stall at times! > > Why couldn't it find level irq capability? What kernel tree/headers are you > using? Ugh - I was building that one manually with old headers. No change with recent ones though. I hit the change in behavior through autotest, where I build everything with proper headers. > >> (gdb) l *0xc000e344 >> 0xc000e344 is at arch/powerpc/kernel/idle_e500.S:74. >> 69 oris r7,r7,MSR_WE@h >> 70 ori r7,r7,MSR_EE >> 71 msync >> 72 mtmsr r7 >> 73 isync >> 74 2: b 2b >> 75 >> 76 /* >> 77 * Return from NAP/DOZE mode, restore some CPU specific registers, >> 78 * r2 containing physical address of current. > > So, the guest is idle. > > Are you using i/o thread? I had very similar problems without it, IIRC > before making any of these changes. This is without i/o thread, as that one's still got shortcomings on PPC and is considered unstable :). My tests worked fine without iothread before your patches, now they break. This could however be related to us getting less exits from the VM. It could also be a bug in the magic page code. Still trying to debug it. Alex -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
