On 14/09/2016 04:33, Michael S. Tsirkin wrote: > Frankly I don't understand why do you need to mess with boot at all. > Quoting the cover letter: > > SEV is designed to protect guest VMs from a benign but vulnerable > (i.e. not fully malicious) hypervisor. In particular, it reduces the > attack > surface of guest VMs and can prevent certain types of VM-escape bugs > (e.g. hypervisor read-anywhere) from being used to steal guest data. > > it seems highly unlikely that any secret data is used during boot. > So just let guest boot normally, and encrypt afterwards. > > Even assuming there are some guests that have secret data during boot, > I would first upstream the main part of the feature for normal guests, > then weight the extra security if any against the features and > performance lost (like slower boot times).
If you can't trust boot, any encryption done afterwards is totally pointless. Paolo
