Re: [RFC] perf/x86: Only expose userspace rdpmc for events on current CPU

2021-01-12 Thread Rob Herring
On Tue, Jan 12, 2021 at 11:05 AM Peter Zijlstra wrote: > > On Tue, Jan 12, 2021 at 10:16:50AM -0600, Rob Herring wrote: > > On Tue, Jan 12, 2021 at 9:33 AM Peter Zijlstra wrote: > > > > > > On Thu, Jan 07, 2021 at 05:01:36PM -0700, Rob Herring wrote: > > > > Userspace access using rdpmc only make

Re: [RFC] perf/x86: Only expose userspace rdpmc for events on current CPU

2021-01-12 Thread Peter Zijlstra
On Tue, Jan 12, 2021 at 10:16:50AM -0600, Rob Herring wrote: > On Tue, Jan 12, 2021 at 9:33 AM Peter Zijlstra wrote: > > > > On Thu, Jan 07, 2021 at 05:01:36PM -0700, Rob Herring wrote: > > > Userspace access using rdpmc only makes sense if the event is valid for > > > the current CPU. However, ca

Re: [RFC] perf/x86: Only expose userspace rdpmc for events on current CPU

2021-01-12 Thread Rob Herring
On Tue, Jan 12, 2021 at 9:33 AM Peter Zijlstra wrote: > > On Thu, Jan 07, 2021 at 05:01:36PM -0700, Rob Herring wrote: > > Userspace access using rdpmc only makes sense if the event is valid for > > the current CPU. However, cap_user_rdpmc is currently set no matter which > > CPU the event is asso

Re: [RFC] perf/x86: Only expose userspace rdpmc for events on current CPU

2021-01-12 Thread Peter Zijlstra
On Thu, Jan 07, 2021 at 05:01:36PM -0700, Rob Herring wrote: > Userspace access using rdpmc only makes sense if the event is valid for > the current CPU. However, cap_user_rdpmc is currently set no matter which > CPU the event is associated with. The result is userspace reading another > CPU's even