On Mon, Jun 29, 2009 at 05:54:46PM +0300, Avi Kivity wrote: > On 06/29/2009 05:39 PM, Joerg Roedel wrote: >> On Mon, Jun 29, 2009 at 04:41:17PM +0300, Avi Kivity wrote: >> >>> kerneloops.org shows tons of oopses on amd, see >>> http://www.kerneloops.org/oops.php?number=79008. I suspect this has to >>> do with resuming a laptop while a guest is running. Can anyone confirm >>> or deny? >>> >> >> I havn't verified this yet but it may have to do with dirty caches that >> are not written back to memory in suspend-to-ram and are thus lost. > > Wouldn't that kill resume generally, not just kvm on amd? Its a race condition which may be more likely on one hardware than on another. I remember similar bugs fixed by Mark in the past. >> The >> resume code-path looks otherwise sane to me. The only thing I can >> imagine is that a bit in the cpu_hardware_enabled cpumask is wrong after >> resume. >> > > I saw some of these oopses on cpu 0, which had better be plugged in. Yeah, but if this bit is set to 0 on suspend and this change does not make it from cache to main memory it can still be 1 on resume. And virtualization hardware will not be re-enabled then. Anyway, this was only a guess from me. I think we should reproduce this oops and find out what is really going on. >> Btw. it is guaranteed that with cpu-hotplug the cpu isn't already >> executing processes when the CPU_ONLINE event call chain is called? >> At least the CPU is marked online and active at that point in time. >> > > Yes: > > static struct notifier_block kvm_cpu_notifier = { > .notifier_call = kvm_cpu_hotplug, > .priority = 20, /* must be > scheduler priority */ > }; Ok. > One thing I think is missing is a call to svm_cpu_init() on real hotplug. Yes, true. There is no svm_data allocated for cpus not online on module load. Joerg -- 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
