On Fri, Oct 16, 2020 at 12:38:47PM +0100, Suzuki Kuruppassery Poulose wrote: [...] > > > What happens to the sysfs mode of tracing? For that we would still > > > need a config right to exclude kernel mode tracing completely. > > > > IIUC, sysfs mode and perf mode both can apply the same approach, the > > guest OS runs a thread context for the host, so when a guest OS is > > switched in or out, the hypervisor can save/restore the context for > > the guest OS; thus every guest OS will have its dedicated context and > > trace data ideally. > > I don't think Guest Context is something we can support as mentioned > above, at least for systems without sysreg access for ETMs (and virtualizing > ETRs is a different story !) Thanks for sharing thoughts, Suzuki. I missed the device virtulisation. Here should virtualize all devices (includes CoreSight ETM/funnel/ETR/ETF)? Or only need to virtualize ETRs? Obviously, this is a difficult task :) Thanks, Leo
