Launchpad has imported 7 comments from the remote bug at http://bugs.meego.com/show_bug.cgi?id=10075.
If you reply to an imported comment from within Launchpad, your comment will be sent to the remote bug automatically. Read more about Launchpad's inter-bugtracker facilities at https://help.launchpad.net/InterBugTracking. ------------------------------------------------------------------------ On 2010-11-16T01:36:48+00:00 Muralidharan-jayavelu wrote: BUILD IMAGE(meego-handset-ia32-qemu-1.1.20101031.2201-sda-runtime): HARDWARE MODEL (on what HW this bug is uncovered): BUG DETAILED DESCRIPTIONS =========================================================== Trying to install and launch QEMU for handset by following instructions using the below link. http://wiki.meego.com/SDK/Docs1.1 Configuring_QEMU_runtimes After installation, trying to poweron the emulator using 'mad remote -r meego-handset-ia32-qemu-1.1.20101031.2201-sda-runtime poweron'. QEMU launches and stuck up in the boot mode. EXPECTED OUTCOME: =================== QEMU should launch successfully and should show the home screen of meego handset. ACTUAL OUTCOME: =================== QEMU is stuck up in the boot mode, showing messages like, " Starting SeaBIOS (version .... ) gPXE ..... Booting from hard disk .... " USER IMPACT: =================== Unable to use QEMU emulator for development. OTHER COMMENTS: =================== Using Meego SDK in Ubuntu 10.10. Reply at: https://bugs.launchpad.net/meego/+bug/688085/comments/0 ------------------------------------------------------------------------ On 2010-11-20T04:54:03+00:00 Fathi-boudra wrote: Please, specify target build and set the status to "accepted" if you work on the issue. Reply at: https://bugs.launchpad.net/meego/+bug/688085/comments/1 ------------------------------------------------------------------------ On 2010-12-16T03:50:08+00:00 Zhiyuan-lv wrote: *** Bug 11378 has been marked as a duplicate of this bug. *** Reply at: https://bugs.launchpad.net/meego/+bug/688085/comments/4 ------------------------------------------------------------------------ On 2010-12-16T03:51:39+00:00 Zhiyuan-lv wrote: Copied from #11271 and #11378 Some findings of the QEMU-KVM issue on Ubuntu 10.10. The QEMU-KVM hung during booting up meego-netbook kernel. The netbook kernel is 2.6.35 with some Intel patches. I did below test: QEMU: 1, qemugl in MeeGo 1.1 SDK, which version is 0.12.4 2, qemu installed from Ubuntu 10.10 repo, which version is 0.12.5 Kernel: a, handset netbook kernel in MeeGo 1.1 release, major version is 2.6.35 b, Ubuntu 10.10 kernel, major version is 2.6.35 Result 1 to boot a FAIL 1 to boot b SUCCESS 2 to boot a FAIL 2 to boot b SUCCESS So the problem is quite like that MeeGo kernel has something special which cannot work well with the KVM in Ubuntu 10.10 host kernel. Reply at: https://bugs.launchpad.net/meego/+bug/688085/comments/5 ------------------------------------------------------------------------ On 2010-12-20T21:30:01+00:00 Zhiyuan-lv wrote: With gdb to debug kernel running inside QEMU, it could be seen that QEMU hangs at below inline asm code: kernel-netbook-2.6.35.3/linux-2.6.35/arch/x86/include/asm/cmpxchg_32.h static inline void set_64bit(volatile u64 *ptr, u64 value) { u32 low = value; u32 high = value >> 32; u64 prev = *ptr; asm volatile("\n1:\t" LOCK_PREFIX "cmpxchg8b %0\n\t" "jnz 1b" : "=m" (*ptr), "+A" (prev) : "b" (low), "c" (high) : "memory"); ...... } The trace is as below: #0 0xc1742bd9 in set_64bit () at /home/abuild/rpmbuild/BUILD/kernel-netbook-2.6.35.3/linux-2.6.35/arch/x86/include/asm/cmpxchg_32.h:74 #1 native_set_pmd () at /home/abuild/rpmbuild/BUILD/kernel-netbook-2.6.35.3/linux-2.6.35/arch/x86/include/asm/pgtable-3level.h:41 #2 pmd_populate_kernel () at /home/abuild/rpmbuild/BUILD/kernel-netbook-2.6.35.3/linux-2.6.35/arch/x86/include/asm/pgalloc.h:66 #3 early_ioremap_init () at arch/x86/mm/ioremap.c:382 #4 0xc173518c in ?? () #5 0xc1733545 in start_kernel () at init/main.c:573 #6 0xc17330ca in i386_start_kernel () at arch/x86/kernel/head32.c:72 #7 0x00000000 in ?? () Reply at: https://bugs.launchpad.net/meego/+bug/688085/comments/6 ------------------------------------------------------------------------ On 2010-12-26T05:05:07+00:00 Zhiyuan-lv wrote: Update some more investigation result. The KVM (in 2.6.35.23 linux kernel on Ubuntu 10.10) seems to hang in __vcpu_run() in arch/x86/kvm/x86.c. When the client OS is running above instruction, KVM goes into dead loop in __vcpu_run(), because the "vcpu_enter_guest ()" always returns "1". The scenario seems to be as follow: The instruction triggered page fault to exit kvm guest, and then "kvm_mmu_page_fault" was called to handle the exception. The function returns non-zero value to let instruction be run again, and suppose that the page fault has been resolved. But for some reason, the page-fault exception was still triggered, and code run infinitely in the loop. Reply at: https://bugs.launchpad.net/meego/+bug/688085/comments/7 ------------------------------------------------------------------------ On 2010-12-27T01:15:13+00:00 Zhiyuan-lv wrote: Update some findings through GooGle: 1, Similar KVM hanging issues were reported, like: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/688085 According to the fix from Avi Kivity, it looks like a bug in KVM handling 64-bit operand of "cmpxchg8b". But it is interesting that KVM on Ubuntu 10.04 and ubuntu 9.10 did not encounter the hanging issue running the 2.6.35 guest kernel. http://www.spinics.net/lists/kvm/msg40800.html Will try the kernel built from latest git tree to see whether the problem could be resolved. 2, Below one seems to be discussing the similar problem but for different root cause. Just a note here. The patched mentioned in below link is still not found in the kernel gitorious tree. http://kerneltrap.org/mailarchive/linux-kernel/2010/8/3/4601781 Reply at: https://bugs.launchpad.net/meego/+bug/688085/comments/8 ** Changed in: meego Status: Unknown => In Progress ** Changed in: meego Importance: Unknown => Critical -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/688085 Title: Guest kernel hang during boot when KVM is active on i386 host Status in meego project: In Progress Status in QEMU: Fix Released Status in qemu-kvm: Fix Released Status in “kvm” package in Ubuntu: Invalid Status in “linux” package in Ubuntu: In Progress Status in “qemu” package in Ubuntu: Invalid Status in “qemu-kvm” package in Ubuntu: Invalid Status in “kvm” source package in Maverick: New Status in “linux” source package in Maverick: New Status in “qemu” source package in Maverick: New Status in “qemu-kvm” source package in Maverick: New Bug description: Binary package hint: qemu Guest kernel hang during boot when KVM is active on i386 host See the patch. http://www.spinics.net/lists/kvm/msg40800.html How to reproduce: 1. install Maversick x86 (not amd64) 2. ensure you have kvm support in processor 3. kvm -kernel /boot/initrd.img-2.6.35-24-generic-pae 4. kvm -no-kvm -kernel /boot/initrd.img-2.6.35-24-generic-pae works OK. SRU Justification: Impact: Users cannot boot KVM guests on i386 hosts 2. How bug addressed: The upstream commit at http://www.spinics.net/lists/kvm/msg40800.html fixed it 3. Patch: A kernel patch is attached to this bug. 4. Reproduce: boot an i386 kernel on a kvm-capable host. Try to boot a kvm guest. 5. Regression potential: since this is cherrypicking a commit from a future upstream which had already been changed, regression is possible. However if there is a regression, it should only affect users of KVM on i386 hosts, which currently fail anyway.
