Il 21/08/2014 14:19, Nadav Amit ha scritto: >> > >> > He meant they are passed as zero in the WRMSR but actually they're not >> > zeroed. They're set to the value that is passed to kvm_set_shared_msr, >> > and this value is massaged elsewhere to do mix guest and host bugs. See >> > update_transition_efer. >> > >> > So I'm removing this patch, it's wrong. > I stand corrected - they are massaged in update_transition_efer. > > The question is whether this massaging is specific to EFER, or a general one. > Currently update_transition_efer does: > > guest_efer &= ~ignore_bits; > guest_efer |= host_efer & ignore_bits; > vmx->guest_msrs[efer_offset].data = guest_efer; > > I think this is a general behaviour - taking the masked bits from the > host, and the rest from the guest. Therefore, it makes sense to put > this logic into kvm_set_shared_msr. I understand the EFER is > currently the only MSR which is only partially masked. Nonetheless, > kvm_set_shared_msr can be useful for other purposes. Yes, I agree. But right now it's not particularly interesting to do it: you're not using the functionality in e.g. the MISC_ENABLE patch, so it's just a matter of defining the semantics of the .data field, basically. 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
