I guessed the cause of the error is really somewhere else - nothing to do with this part. But without a full view of the entire source - it is hard to diagnose the bugs. (Perhaps even more difficult if full view is available). But I have no problem insmod lg.ko in drivers/lguest directory (after CONFIG_LGUEST is set to "m"), and lguest is not a simple example I must say. And to get a better understanding on how to use the kvm_hypercall APIs, just go to the kernel source's drivers/lguest directory and enter "make" and it will churns lots of information (totalling about 7000+ lines) teaching you the basic of KVM - both how the KVM hypervisor works, and how the lguest work. And if u are lazy to do a "make" this is my version: https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B1hg6_FvnEa8ZjFjMDQxNzAtZDAyZC00MDA2LTk3YmMtNGE5YjdjZDM0Nzc3&hl=en_US On Thu, Jun 9, 2011 at 4:35 PM, emilie lefebvre <tricheurs@xxxxxxxxxx> wrote: > Hi, > I try this : > > local_irq_save(flags); > kvm_hypercall2 ( 6, 2, 2); > local_irq_restore(flags); > > But I still have my kernel panic with "divide error: 0000 [#1] SMP" that I > don't understand! > with or without lock, nothing change, the same when I change the current > state. > > I tried to move my hypercall and I still don't understand why it works just > before my test > "if (piga_on == 1)" without any protections (like disable interrupts) and > not after.. > > Thank you for trying to help me > > >> Date: Thu, 9 Jun 2011 09:46:12 +0800 >> Subject: Re: Problems with hypercalls >> From: htmldeveloper@xxxxxxxxx >> To: tricheurs@xxxxxxxxxx >> CC: kernelnewbies@xxxxxxxxxxxxxxxxx >> >> perhaps this example will provide u with more info: >> >> http://a380.informatik.uni-bremen.de/lxr/source/arch/x86/lguest/boot.c >> >> I think the correct step is to disable IRQ instead - before every call >> to kvm_hypercallX(). The reason is given in the remark: >> >> 110 /* >> 111 * Disable interrupts if not already disabled: we don't want an >> 112 * interrupt handler making a hypercall while we're already doing >> 113 * one! >> 114 */ >> >> On Wed, Jun 8, 2011 at 10:54 PM, emilie lefebvre <tricheurs@xxxxxxxxxx> >> wrote: >> > >> > This is my function : >> > >> > static spinlock_t xgr_learn_lock = SPIN_LOCK_UNLOCKED; >> > static int piga_seq_cpt = 1; >> > >> > /* >> > * Function called for each systemcall (Hook SELinux avc function) >> > */ >> > int piga_control(u32 ssid, ...., struct av_decision * avd) { >> > >> > /* >> > * Here my hypercall work but block my vm with this error : >> > * " BUG: scheduling while atomic ... " >> > */ >> > >> > spin_lock_bh(&xgr_learn_lock); >> > if ( in_atomic()) >> > kvm_hypercall2 ( 6, (unsigned long)2 ,(unsigned >> > long)piga_seq_cpt); >> > spin_unlock_bh(&xgr_learn_lock); >> > >> > if (piga_on == 1) { >> > /* >> > * Here my hypercall make a kernel panic with this error: >> > * " divide error: 0000 [#1] SMP" >> > */ >> > spin_lock_bh(&xgr_learn_lock); >> > set_current_state(TASK_UNINTERRUPTIBLE); >> > kvm_hypercall2 ( 6, (unsigned long)2 ,(unsigned >> > long)piga_seq_cpt); >> > set_current_state(TASK_RUNNING); >> > spin_lock_bh(&xgr_learn_lock); >> > } >> > } >> > >> > >> >> I think u generally set TASK_UNINTERRUPTIBLE whenever about to modify >> the scheduling task list (eg, wait queue manipulation) or about to >> call "schedule()" (ie, doing your own scheduling). The function >> set_current_state() literally just set the variable value only, it >> does not disable interrupt. >> >> -- >> Regards, >> Peter Teoh >> >> _______________________________________________ >> Kernelnewbies mailing list >> Kernelnewbies@xxxxxxxxxxxxxxxxx >> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies@xxxxxxxxxxxxxxxxx > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > -- Regards, Peter Teoh _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
