On Wed, Apr 03, 2013 at 08:00:37PM +0800, Zhenzhong Duan wrote: > > On 2013-04-01 20:41, Konrad Rzeszutek Wilk wrote: > >On Mon, Apr 01, 2013 at 01:26:34PM +0800, Zhenzhong Duan wrote: > >>On 2013-03-29 21:46, Konrad Rzeszutek Wilk wrote: > >>>On Fri, Mar 29, 2013 at 03:22:38PM +0800, Zhenzhong Duan wrote: > >>The problem is even without overwrite, like xapic system, > >>xen_send_IPI_all doesn't work for nmi vector. > >Can you tweak the x2apic_mode = 0 in enligthen.c for example? > >Or clear the X86_FEATURE_X2APIC in the enlighten.c ? (Similar > >to how the other features are cleared) Wouldn't > >that stop x2apic_enabled from detecting x2APIC? > Hi Konrad, > I used the second method. x2apic is totally masked in dom0. Thanks > Tamon to do the test. > > Testing result: > > The server didn't get crashed by "echo l > /proc/sysrq-trigger". On this > machine, VT-d is enabled in BIOS. > However, no backtrace was shown. > > [root@x4470m2-bur09-b ~]# uname -a > Linux x4470m2-bur09-b.us.oracle.com 2.6.39-200.1.14.el5uek.bug16372098.test > #1 SMP Tue Apr 2 21:09:27 PDT 2013 x86_64 x86_64 x86_64 GNU/Linux > [root@x4470m2-bur09-b ~]# cat /proc/cpuinfo | grep x2apic > [root@x4470m2-bur09-b ~]# dmesg | grep x2apic > [root@x4470m2-bur09-b ~]# cat /proc/cmdline > ro root=UUID=486fc42b-3383-462f-aca3-b1340fbd4ad9 console=tty1 > console=ttyS0,9600n8 > [root@x4470m2-bur09-b ~]# echo l > /proc/sysrq-trigger > [root@x4470m2-bur09-b ~]# > > /var/log/messages: > (snip) > Apr 3 14:14:33 x4470m2-bur09-b kernel: SysRq : Show backtrace of all active > CPUs > Apr 3 14:14:33 x4470m2-bur09-b kernel: sending NMI to all CPUs: > (EOF) > > On the console, no backtrace either. I did it twice, and got the same results.
Great. Zhenzhong, do you want to prep a patch with a nice git commit description mentioning your findings of the x2APIC over-write and also include the crach that would appear? And send it to xen-devel + LKML and to me so I can put it on my v3.9 branch? Thanks > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
