On September 14, 2016 6:17:51 PM PDT, Andy Lutomirski <l...@amacapital.net> wrote: >On Wed, Sep 14, 2016 at 3:03 PM, Kyle Huey <m...@kylehuey.com> wrote: >> On Wed, Sep 14, 2016 at 2:35 PM, Dave Hansen >> <dave.han...@linux.intel.com> wrote: >>> On 09/14/2016 02:01 PM, Kyle Huey wrote: > >>> Is any of this useful to optimize away at compile-time? We have >config >>> options for when we're running as a guest, and this seems like a >feature >>> that isn't available when running on bare metal. >> >> On the contrary, this is only available when we're on bare metal. >> Neither Xen nor KVM virtualize CPUID faulting (although KVM correctly >> suppresses MSR_PLATFORM_INFO's report of support for it). > >KVM could easily support this. If rr starts using it, I think KVM >*should* add support, possibly even for older CPUs that don't support >the feature in hardware. > >It's too bad that x86 doesn't give us the instruction bytes on a >fault. Otherwise we could lazily switch this feature. > >--Andy
You can "always" examine the instruction bytes in memory... have to make sure you properly consider the impact of race conditions though. -- Sent from my Android device with K-9 Mail. Please excuse brevity and formatting. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
