Joerg Roedel <joro@xxxxxxxxxx> writes: > On Tue, Oct 06, 2015 at 01:59:27PM -0400, Bandan Das wrote: >> Joerg Roedel <joro@xxxxxxxxxx> writes: >> > >> > So svm->vmcb->control.next_rip is only written by hardware or in >> > svm_check_intercept(). Both cases write only to this field, if the >> > hardware supports X86_FEATURE_NRIPS. The write in nested_svm_vmexit only >> >> Not until commit f104765b4f81fd74d69e0eb161e89096deade2db. So, an older L1 >> kernel will trigger it. > > But we don't care if L1 writes something into its own next_rip, as we > never read this value from its VMCB. We only copy the next_rip value we > get from our shadow-vmcb to it on an emulated vmexit. So I still don't > understand what triggers the reported problem or why the WARN_ON is > necessary. Ok, looks like I am making some incorrect "vmx" assumptions here. What happens when we exit from L2 to L0, arent' we looking at the VMCB L1 is using to run L2 ? Wouldn't that trigger the warning if the host processor does not support nrips and the field is set ? > > 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
