On Thu, Oct 1, 2015 at 12:15 AM, Ingo Molnar <mi...@kernel.org> wrote: > > * Andy Lutomirski <l...@amacapital.net> wrote: > >> > These could still be open coded in an inlined fashion, like the scheduler >> > usage. >> >> We could have a raw_rdmsr for those. >> >> OTOH, I'm still not 100% convinced that this warn-but-don't-die behavior is >> worth the effort. This isn't a frequent source of bugs to my knowledge, and >> we >> don't try to recover from incorrect cr writes, out-of-bounds MMIO, etc, so >> do we >> really gain much by rigging a recovery mechanism for rdmsr and wrmsr failures >> for code that doesn't use the _safe variants? > > It's just the general principle really: don't crash the kernel on bootup. > There's > few things more user hostile than that. > > Also, this would maintain the status quo: since we now (accidentally) don't > crash > the kernel on distro kernels (but silently and unsafely ignore the faulting > instruction), we should not regress that behavior (by adding the chance to > crash > again), but improve upon it.
Just a heads up: the extable improvements in tip:ras/core make it straightforward to get the best of all worlds: explicit failure handling (written in C!), no fast path overhead whatsoever, and no new garbage in the exception handlers. Patches coming once I test them. > > Thanks, > > Ingo -- Andy Lutomirski AMA Capital Management, LLC _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel