On Fri, May 14, 2010 at 04:26:11PM +0200, Alexander Graf wrote: > > On 14.05.2010, at 15:15, Matteo Signorini wrote: > > > Hi to all, > > > > I am working on NPT and have some doubts. > > Please correct me if I am wrong, > > > > In NPT only the first time a page fault happens it is trapped by the host. > > The following page faults are not trapped by the host in order to > > reduce page walk overhead. > > > > My question is... > > > > Which Kvm function handles the "nested page fault"? > > The exit code is SVM_EXIT_NPF. Just search for the handler in svm.c:svm_exit_handlers. > > [SVM_EXIT_NPF] = pf_interception, Which ends up in tdp_page_fault(). This function calls the generic __direct_map() handler (that is used for real-mode paging too). Note that nested page faults are different from guest page faults. Guest page faults occur for guest virtual addresses (and are handled entirely inside the guest most of the time) while nested page faults occur for guest physical addresses and are alway handled by kvm. 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
