https://bugzilla.kernel.org/show_bug.cgi?id=53631 Summary: nVMX: Support exit/entry MSR load/store Product: Virtualization Version: unspecified Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: kvm AssignedTo: virtualization_kvm@xxxxxxxxxxxxxxxxxxxx ReportedBy: nyh@xxxxxxxxxxxxxxxxxxx Regression: No Currently, nested VMX does not allow L1 to use the MSR load/store feature on entry/exit. The code fails entry (from L1 to L2) if these VMCS features are used: if (vmcs12->vm_entry_msr_load_count > 0 || vmcs12->vm_exit_msr_load_count > 0 || vmcs12->vm_exit_msr_store_count > 0) { pr_warn_ratelimited("%s: VMCS MSR_{LOAD,STORE} unsupported\n", __func__); nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD); return 1; } This was not a big problem if L1 is also KVM, because KVM didn't use this feature - it only uses it in case of EPT for switching the EFER (see explanation in http://kerneltrap.org/mailarchive/linux-kvm/2010/5/2/6261577), and in that case there is a simpler alternative: supporting VM_ENTRY/EXIT_LOAD_IA32_EFER is enough. So this is what we did in the nested EPT patches proposed in bug 53611. However, it is likely that for different L1s (or even KVM in the future), we'll need to support the generic MSR load/store feature. -- Configure bugmail: https://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are watching the assignee of the bug. -- 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
