On Tue, Aug 11, 2020 at 04:31:10PM +0800, Jin, Yao wrote: > Hi Peter, > > On 8/11/2020 3:59 PM, Peter Zijlstra wrote: > > On Tue, Aug 11, 2020 at 03:50:43PM +0800, Jin, Yao wrote: > > > Could I post v2 which basically refers to your patch but removes some > > > conditions since I see some issues in test if we use these conditions. > > > > > > 1. Remove '!event->attr.exclude_hv || !event->attr.exclude_host || > > > !event->attr.exclude_guest' at the entry of sanitize_sample_regs(). > > > > > > 2. Remove '!attr.exclude_hv || !attr.exclude_host || > > > !attr.exclude_guest' > > > at the perf_event_open syscall entry. > > > > exclude_host, maybe -- due to the dodgy semantics of it, but the others > > should definitely be there. > > > > exclude_guest and exclude_hv are tricky too. > > If we do 'perf record -e cycles:u' in both host and guest, we can see: > > event->attr.exclude_guest = 0 > > thus sanitize_sample_regs() returns regs directly even if exclude_kernel = 1. > > And in guest, exclude_hv = 0, it's out of my expectation too.
I'm confused, how can 'perf record -e cycles:u' _ever_ have exclude_guest=0, exclude_hv=0 ? That simply makes no sense and is utterly broken. You explicitly ask for userspace-only, reporting hypervisor or guest events is a straight up bug.
