Il 03/07/2013 10:46, Zhang, Yang Z ha scritto: > >> Il 03/07/2013 10:24, Arthur Chunqi Li ha scritto: >>> Hi Gleb and Paolo, >>> When I write test cases for nested virt and found that reading/writing >>> IA32_FEATURE_CONTROL will be simply ignored or return 0 (in >>> arch/x86/kvm/vmx.c) in VM. Checking this MSR will be done by some >>> hypervisors (e.g. NOVA) and may cause error then, so it is necessary >>> to behave right when read/write it in VM. >>> >>> Are there any difficulties to handle this MSR? I have two solutions. >>> The first one is return the value of physical CPU's and always return >>> true when write. This is simple but may behave as if it is a VM >>> because write to it after VMXON will not return GP exception. This >>> solution can solve most basic problems since this MSR is not commonly >>> used. Another solution is adding a field in VCPU to handle this MSR. >>> This is a complex but better method. >>> >>> I think I can complete this if needed. >> >> Would it be enough to return 5 (binary 101) on reads if nested VMX is enabled, and #GP on writes? > Agree!, It should be enough. You cannot return physical value directly since there is no SMX in nested. Arthur, are you writing a patch? Paolo -- 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
