On 26.11.2021 22:22, Andrew Cooper wrote: > Slightly RFC, because patch 2 has some minor structure (ab)use, but the result > works alarmingly well. So far, this demonstrates converting two subsystems. > > hvm_funcs is the other area of especially low hanging fruit, but IOMMU, vPMU > also look like good candidates. Anything which is partially altcall'd already > would benefit from being fully altcall'd.
I'll post patches for hvm_funcs and vPMU hopefully later today. I intend to look into the remaining unconverted IOMMU instances (so far I've spotted one, but proper auditing may turn up more). For hvm_funcs what I have leaves a few ones still unconverted; I guess we can discuss whether to go beyond what I have in the context of that patch. > Should we consider introducing __ro_after_init right now (as an alias to > __read_mostly) as this conversion is touching a lot of ares where true > post-init immutability ought to be enforced. Well, it's largely orthogonal, but this might indeed be a good opportunity to at least make a first step. I'd go slightly beyond what you say and at least also introduce a respective new section, rather than aliasing __read_mostly. Jan > Andrew Cooper (4): > x86/altcall: Check and optimise altcall targets > x86/altcall: Optimise away endbr64 instruction where possible > xen/xsm: Use __init_data_cf_clobber for xsm_ops > x86/ucode: Use altcall, and __initdata_cf_clobber > > xen/arch/x86/alternative.c | 60 > ++++++++++++++++++++++++++++++++++++ > xen/arch/x86/cpu/microcode/amd.c | 2 +- > xen/arch/x86/cpu/microcode/core.c | 38 ++++++++++++----------- > xen/arch/x86/cpu/microcode/intel.c | 2 +- > xen/arch/x86/cpu/microcode/private.h | 2 +- > xen/arch/x86/xen.lds.S | 5 +++ > xen/include/xen/init.h | 2 ++ > xen/xsm/dummy.c | 2 +- > xen/xsm/flask/hooks.c | 2 +- > xen/xsm/silo.c | 2 +- > 10 files changed, 93 insertions(+), 24 deletions(-) >
