On Mon, Jul 14, 2025 at 12:20:22PM +0200, Peter Zijlstra wrote: > What used to be a simple few instructions has turned into a giant mess > (for x86_64). Not only does it use static_branch wrong, it mixes it > with dynamic branches for no apparent reason. > > Notably it uses static_branch through an out-of-line function call, > which completely defeats the purpose, since instead of a simple > JMP/NOP site, you get a CALL+RET+TEST+Jcc sequence in return, which is > absolutely idiotic. > > Add to that a dynamic test of hyperv_paravisor_present, something > which is set once and never changed. > > Replace all this idiocy with a single direct function call to the > right hypercall variant. > > Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> > Tested-by: Michael Kelley <mhklinux@xxxxxxxxxxx> > Reviewed-by: Michael Kelley <mhklinux@xxxxxxxxxxx> Acked-by: Wei Liu <wei.liu@xxxxxxxxxx>
