On Thu, Dec 1, 2016 at 1:22 AM, Borislav Petkov <[email protected]> wrote: > On Wed, Nov 30, 2016 at 12:34:55PM -0800, Andy Lutomirski wrote: >> Aside from being excessively slow, CPUID is problematic: Linux runs >> on a handful of CPUs that don't have CPUID. MOV to CR2 is always >> available, so use it instead. >> >> Signed-off-by: Andy Lutomirski <[email protected]> >> --- >> arch/x86/include/asm/processor.h | 31 ++++++++----------------------- >> 1 file changed, 8 insertions(+), 23 deletions(-) > > Looks nice. > > I'm wondering if we should leave this one in tip for an additional cycle > to have it tested on more hw. I know, it is architectural and so on but > who knows what every implementation actually does...
I want the Xen opinion as well. Xen folks, can Linux use write_cr2 to serialize the CPU core on Xen PV or do we need something a bit heavier weight like native_write_cr2? --Andy
