Re: [PATCH] x86/paravirt: use %rip-relative addressing in hook calls

On 30.09.21 14:40, Jan Beulich via Virtualization wrote:

While using a plain (constant) address works, its use needlessly invokes
a SIB addressing mode, making every call site one byte larger than
necessary. Instead of using an "i" constraint with address-of operator
and a 'c' operand modifier, simply use an ordinary "m" constraint, which
the 64-bit compiler will translate to %rip-relative addressing. This way
we also tell the compiler the truth about operand usage - the memory
location gets actually read, after all.

32-bit code generation is unaffected by the change.

Signed-off-by: Jan Beulich <redacted>

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen