diff --git a/basics_dev/devel-faq.md b/basics_dev/devel-faq.md index f5d347ab..6a21b99d 100644 --- a/basics_dev/devel-faq.md +++ b/basics_dev/devel-faq.md @@ -16,8 +16,8 @@ Why does dom0 need to be 64-bit? Since 2013 [Xen has not supported 32-bit x86 architecture](http://wiki.xenproject.org/wiki/Xen_Project_Release_Features) and Intel VT-d, which Qubes uses to isolate devices and drivers, is available on Intel 64-bit processors only. -In addition, it is often more difficult to bypass ASLR and exploit a bug on x64 Linux than x86 Linux. -While we designed Qubes from the beginning to limit potential attack vectors, we still realize that some of the code running in Dom0, e.g. our GUI daemon or xen-store daemon, even though it is very simple, might contain some bugs. +In addition, with features like improved ASLR, it is often more difficult to exploit a bug on x64 Linux than x86 Linux. +While we designed Qubes from the beginning to limit potential attack vectors, we still realize that some of the code running in Dom0, e.g. our GUI daemon or xen-store daemon, however simple, might contain some bugs. Plus since we haven't implemented a separate storage domain, the disk backends are in Dom0 and are "reachable" from the VMs, which adds up to the potential attack surface. So, having faced a choice between 32-bit and 64-bit OS for Dom0, it was almost a no-brainer. The 64-bit option provides some (little perhaps, but some) more protection against some classes of attacks, and at the same time does not have any disadvantages except the extra requirement of a 64 bit processor.