On 08/08/2025 9:23 pm, Andrew Cooper wrote: > diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig > index a45ce106e210..90cbad13a7c7 100644 > --- a/xen/arch/x86/Kconfig > +++ b/xen/arch/x86/Kconfig > @@ -57,6 +57,10 @@ config HAS_CC_CET_IBT > # Retpoline check to work around > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 > def_bool $(cc-option,-fcf-protection=branch -mmanual-endbr > -mindirect-branch=thunk-extern) && $(as-instr,endbr64) > > +config HAS_AS_FRED > + # binutils >= 2.41 or LLVM >= 19 > + def_bool $(as-instr,eretu;lkgs %ax) > + > menu "Architecture Features" > > source "arch/x86/Kconfig.cpu" > diff --git a/xen/arch/x86/include/asm/asm-defns.h > b/xen/arch/x86/include/asm/asm-defns.h > index 61a5faf90446..2e5200b94b82 100644 > --- a/xen/arch/x86/include/asm/asm-defns.h > +++ b/xen/arch/x86/include/asm/asm-defns.h > @@ -4,6 +4,15 @@ > .byte 0x0f, 0x01, 0xfc > .endm > > +#ifndef CONFIG_HAS_AS_FRED > +.macro eretu > + .byte 0xf3, 0x0f, 0x01, 0xca > +.endm > +.macro erets > + .byte 0xf2, 0x0f, 0x01, 0xca > +.endm > +#endif
Seeing as I know you are going to be unhappy with the Kconfig... I think I'm dev complete on the PV support now, and there's not an LKGS in sight. We don't strictly need the conditional in asm-defns.h, and if we don't need it in C either then we can drop the Kconfig entirely. ~Andrew
