On Wed, Aug 07, 2013 at 08:31:04AM +0000, Bhushan Bharat-R65777 wrote: > > > > -----Original Message----- > > From: Paul Mackerras [mailto:paulus@xxxxxxxxx] > > Sent: Wednesday, August 07, 2013 1:58 PM > > To: Bhushan Bharat-R65777 > > Cc: Alexander Graf; Benjamin Herrenschmidt; kvm-ppc@xxxxxxxxxxxxxxx; > > kvm@xxxxxxxxxxxxxxx > > Subject: Re: [PATCH 21/23] KVM: PPC: Book3S PR: Use mmu_notifier_retry() in > > kvmppc_mmu_map_page() > > > > On Wed, Aug 07, 2013 at 05:17:29AM +0000, Bhushan Bharat-R65777 wrote: > > > > > > Pauls, I am trying to understand the flow; does retry mean that we do not > > create the mapping and return to guest, which will fault again and then we will > > retry? > > > > Yes, and you do put_page or kvm_release_pfn_clean for any page that you got. > > Ok, but what is the value to return back to guest when we know it is again going to generate fault. > Cannot we retry within KVM? You can, though you should make sure you include a preemption point. Going back to the guest gets you a preemption point because of the cond_resched() call in kvmppc_prepare_to_enter(). Paul. -- 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
