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) <[email protected]>
> Tested-by: Michael Kelley <[email protected]>
> Reviewed-by: Michael Kelley <[email protected]>

Acked-by: Wei Liu <[email protected]>

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