On 07/31/2012 02:36 AM, Marcelo Tosatti wrote: > On Mon, Jul 30, 2012 at 07:39:31PM +0300, Avi Kivity wrote: >> On 07/30/2012 05:07 PM, Chris Clayton wrote: >> >> >> >>>> With kernel 3.5.0 with b2da15ac26a0c00 reverted, I have just had 15 >> >>>> clean invocations of vanilla qemu-kvm-1.1.1. So that commit would seem >> >>>> to be the problem. >> >>> >> >>> Just to be sure, I've run some more tests today. No crashes occurred in >> >>> 20 runs of vanilla qemu-kvm-1.1.1 on kernel 3.5.0 with b2da15ac26a0c00 >> >>> reverted. >> >> >> >> Ok. I'm trying to reproduce it here on a nested-virt setup, since the >> >> code looks correct. >> >> >> >> What's your preemption settings? >> >> >> >> >> > [chris:~/kernel/linux-3.5.0]$ grep PREEMPT .config >> > CONFIG_TREE_PREEMPT_RCU=y >> > CONFIG_PREEMPT_RCU=y >> > CONFIG_PREEMPT_NOTIFIERS=y >> > # CONFIG_PREEMPT_NONE is not set >> > # CONFIG_PREEMPT_VOLUNTARY is not set >> > CONFIG_PREEMPT=y >> > CONFIG_PREEMPT_COUNT=y >> >> Here's what I think that is happening >> >> vcpu_load >> ... >> vmx_save_host_state >> vmx_vcpu_run >> (ds.cpl, es.cpl cleared by hardware) >> >> interrupt >> push ds, es # pushes bad ds, es >> schedule >> vmx_vcpu_put >> vmx_load_host_state >> reload ds, es >> pop ds, es # of other thread's stack >> iret >> # other thread runs >> interrupt >> schedule # back in vcpu thread >> interrupt return: pop ds, es # <-- problem >> iret >> >> ... >> vcpu_put >> >> # bad ds, es, but !vmx->host_state.loaded >> >> Marcelo, did I miss something here? > > Don't think so. So the same problem should happen with %fs and %gs, no? x86_64 is safe, since it entry_64.S never saves/restores segment registers. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
