From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:46394) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ua0Hz-0005QJ-Bt for qemu-devel@nongnu.org; Wed, 08 May 2013 05:04:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ua0Hu-0001mc-9L for qemu-devel@nongnu.org; Wed, 08 May 2013 05:03:55 -0400 Received: from isrv.corpit.ru ([86.62.121.231]:37790) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ua0Hu-0001kh-0J for qemu-devel@nongnu.org; Wed, 08 May 2013 05:03:50 -0400 Message-ID: <518A14F4.80907@msgid.tls.msk.ru> Date: Wed, 08 May 2013 13:03:48 +0400 From: Michael Tokarev MIME-Version: 1.0 References: <518A0B29.9080903@msgid.tls.msk.ru> In-Reply-To: <518A0B29.9080903@msgid.tls.msk.ru> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] (i386) TCG is broken in 1.5-rc0 with guest kernel 3.2? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel Cc: carl@nextdayvideo.com, Richard Henderson 08.05.2013 12:22, Michael Tokarev wrote: > Something strange is going on here. > > I just tried 1.5-rc0 (32bit x86 userspace), and guest kernel > crashes in an interesting way right at init time. > > qemu-system-x86_64 -net none -kernel /boot/vmlinuz-3.2-amd64 -append console=ttyS0 -serial file:serial > > This results in: > > [ 0.071315] mce: CPU supports 10 MCE banks > [ 0.082316] SMP alternatives: switching to UP code > [ 0.658457] Freeing SMP alternatives: 16k freed > [ 0.660716] ACPI: Core revision 20110623 > [ 0.744749] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1 > [ 0.778545] CPU0: AMD QEMU Virtual CPU version 1.4.90 stepping 03 > [ 0.887450] Performance Events: Broken PMU hardware detected, using software events only. > [ 0.889372] NMI watchdog disabled (cpu0): hardware events not enabled > [ 0.889372] Brought up 1 CPUs > [ 0.889372] Total of 1 processors activated (6432.01 BogoMIPS). > [ 0.889372] devtmpfs: initialized > [ 0.889372] ------------[ cut here ]------------ > [ 0.889372] WARNING: at fs/sysfs/group.c:138 dpm_sysfs_add+0xb4/0xc0() > [ 0.889372] Hardware name: Bochs > [ 0.889372] sysfs group ffffffff814bece0 not found for kobject 'platform' ... This is broken by the following: commit 57eb0cc85469a8948d1036ab830951e63aa32f66 Author: Richard Henderson Date: Wed Jan 16 11:00:14 2013 -0800 target-i386: expand cmov via movcond Signed-off-by: Richard Henderson After this change, (at least) 3.2 kernel starts behaving badly, being unable to boot in qemu TCG mode: > The same happens with other 3.2.x kernels, for example, ubuntu precise: > http://archive.ubuntu.com/ubuntu/dists/precise/main/installer-amd64/current/images/netboot/ubuntu-installer/amd64/linux > > > qemu-system-x86_64 from qemu-1.4.x lets these kernels to boot fine, > it all boots fine when adding -enable-kvm. So it is some change(s) > in TCG between 1.4 and 1.5, maybe triggering a bug in guest kernel. > > For added fun, for example, 3.8 guest kernel does NOT have problems > with this config. I'm trying 64bits now too... /mjt