Alternatives have had a reasonably severe restriction since their introduction. This has been the source of several bugs, and several inefficiencies particularly in the speculative safety paths, and I've finally gotten bored enough to fixing it.
Introduce the new infrastructure, and adjust the BHB scrubbing logic to use it. Andrew Cooper (6): x86: Introduce x86_decode_lite() x86/alternative: Walk all replacements in debug builds x86/alternative: Intend the relocation logic x86/alternative: Replace a continue with a goto x86/alternative: Relocate all insn-relative fields x86/spec-ctrl: Introduce and use DO_COND_BHB_SEQ xen/arch/x86/alternative.c | 210 +++++++++++++------ xen/arch/x86/hvm/vmx/entry.S | 12 +- xen/arch/x86/include/asm/spec_ctrl_asm.h | 43 ++-- xen/arch/x86/x86_emulate/Makefile | 1 + xen/arch/x86/x86_emulate/decode-lite.c | 245 +++++++++++++++++++++++ xen/arch/x86/x86_emulate/private.h | 2 + xen/arch/x86/x86_emulate/x86_emulate.h | 17 ++ 7 files changed, 445 insertions(+), 85 deletions(-) create mode 100644 xen/arch/x86/x86_emulate/decode-lite.c -- 2.30.2
