On 03/19/18 09:53, Konrad Rzeszutek Wilk wrote: >> >> None specifically, but it is otherwise "normal" behavior of some VMs. Apparently it used to be a common method to synchronize writes to other I/O ports. In the commit thread for the original commit no-one was able to reproduce it. There are no details on what processors are impacted or exactly what the "exceptions and instability in the host kernel" were. > > <blinks> There are OSes out there that use a "debug" port to synchronize > I/O port access? That seems ill-advised? What are those OSes? > Linux, most of its bootloaders, and a number of OSes developed after Linux. -hpa
