On Wed, Apr 30, 2025 at 1:26 PM Peter Zijlstra <[email protected]> wrote: > Notably the KVM fastop emulation stuff -- which I've completely rewritten for > this version -- the generated code doesn't look horrific, but is slightly more > verbose. I'm running on the assumption that instruction emulation is not super > performance critical these days of zero VM-exit VMs etc.
It's definitely going to be slower, but I guess it's okay these days. It's really only somewhat hot with really old processors (pre-Westmere) and only when running big real mode code. Paolo > KVM has another; the VMX interrupt injection stuff calls the IDT handler > directly. Is there an alternative? Can we keep a table of Linux functions > slighly higher up the call stack (asm_\cfunc ?) and add CFI to those? > > HyperV hypercall page stuff, which I've previously suggested use direct calls, > and which I've now converted (after getting properly annoyed with that code). > > Also available at: > > git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git x86/core > > Changes since v1: > > - complete rewrite of the fastop stuff > - HyperV tweaks (Michael) > - objtool changes (Josh) > > > [1] > https://lkml.kernel.org/r/[email protected] > [2] https://lkml.kernel.org/r/[email protected] >
