On 23.04.2010, at 16:51, Joerg Roedel wrote: > On Fri, Apr 23, 2010 at 04:42:52PM +0200, Alexander Graf wrote: >> >> On 23.04.2010, at 16:31, Joerg Roedel wrote: >> >>> On Fri, Apr 23, 2010 at 04:24:54PM +0200, Alexander Graf wrote: >>>> >>>> On 23.04.2010, at 16:22, Joerg Roedel wrote: >>> >>>>> No, nested_svm_nmi runs in atomic context where we can't emulate a >>>>> vmexit. We set exit_required and emulate the vmexit later. >>>> >>>> So we modify the L2 rflags and then trigger a #vmexit, leaving the l2 >>>> state broken? >>> >>> No, the rflags are changed in enable_nmi_window which isn't called when >>> we run nested and the nested hypervisor intercepts nmi. So it only runs >>> in the !nested case where it can't corrupt L2 state. >> >> Last time I checked the code enable_nmi_window was the function >> triggering the #vmexit, > > Yes, thats the bug which this patch fixes :-) > >> so it should run in that exact scenario. If what you say is true, where >> do we #vmexit instead then? > > After setting exit_required we run into svm.c:svm_vcpu_run. There the > exit_required flag is checked and if set, the function immediatly > returns without doing a vmrun. A few cycles later we run into > svm.c:handle_exit() where at the beginning exit_required is checked, and > if set the vmexit is emulated. Oh well, I guess I have to trust you on this one :) Alex -- 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
