Worth noting that many of the claims around Spectre are wholly un-demonstrated. The PoC only involves reading memory from within the same process (aka, the PoC read memory through a side channel that it had full ability to read anyway). Trying to exploit this in a different process is entirely undemonstrated, and there's not even any real discussion in the paper of how it would work. In theory it's doable, but the issues around how you do this once process switching and IPC enters the picture seems substantial yet the paper does not make any attempt to tackle any of that.