On Tue, Feb 4, 2020 at 1:37 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > On Tue, Feb 04, 2020 at 05:19:26PM +0800, Xiaoyao Li wrote: > > > > > + case MSR_IA32_CORE_CAPS: > > > > + if (!msr_info->host_initiated) > > > > > > Shouldn't @data be checked against kvm_get_core_capabilities()? > > > > Maybe it's for the case that userspace might have the ability to emulate SLD > > feature? And we usually let userspace set whatever it wants, e.g., > > ARCH_CAPABILITIES. > > If the 'sq_misc.split_lock' event is sufficiently accurate, I suppose > the host could use that to emulate the feature at the cost of one > counter used. I would be impressed if the event were to fire before executing the offending split lock. Wouldn't the best possible result be for it to fire with RIP pointing to the *next* instruction? This seems like it could be quite confusing to a guest.
