From e390f4d69da026149c8c80a7a2218e166d5643fc Mon Sep 17 00:00:00 2001 From: Liam Ni Date: Thu, 8 Sep 2022 22:12:10 +0800 Subject: [PATCH] KVM:x86: Clean up ModR/M "reg" initialization in reg op decoding Refactor decode_register_operand() to get the ModR/M register if and only if the instruction uses a ModR/M encoding to make it more obvious how the register operand is retrieved. Signed-off-by: Liam Ni Link: https://lore.kernel.org/r/20220908141210.1375828-1-zhiguangni01@zhaoxin.com Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/kvm/emulate.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 08dbcff4045a..9367aaaacdf9 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1137,9 +1137,11 @@ static int em_fnstsw(struct x86_emulate_ctxt *ctxt) static void decode_register_operand(struct x86_emulate_ctxt *ctxt, struct operand *op) { - unsigned reg = ctxt->modrm_reg; + unsigned int reg; - if (!(ctxt->d & ModRM)) + if (ctxt->d & ModRM) + reg = ctxt->modrm_reg; + else reg = (ctxt->b & 7) | ((ctxt->rex_prefix & 1) << 3); if (ctxt->d & Sse) { -- 2.11.0