From 02357bdc8c30a60cd33dd438f851c1306c34f435 Mon Sep 17 00:00:00 2001 From: Bandan Das Date: Wed, 16 Apr 2014 12:46:11 -0400 Subject: [PATCH] KVM: emulate: cleanup decode_modrm Remove the if conditional - that will help us avoid an "else initialize to 0" Also, rearrange operators for slightly better code. Signed-off-by: Bandan Das Signed-off-by: Paolo Bonzini --- arch/x86/kvm/emulate.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 000fc7398832..94f5f8b94ce9 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1066,19 +1066,17 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt, struct operand *op) { u8 sib; - int index_reg = 0, base_reg = 0, scale; + int index_reg, base_reg, scale; int rc = X86EMUL_CONTINUE; ulong modrm_ea = 0; - if (ctxt->rex_prefix) { - ctxt->modrm_reg = (ctxt->rex_prefix & 4) << 1; /* REX.R */ - index_reg = (ctxt->rex_prefix & 2) << 2; /* REX.X */ - ctxt->modrm_rm = base_reg = (ctxt->rex_prefix & 1) << 3; /* REG.B */ - } + ctxt->modrm_reg = ((ctxt->rex_prefix << 1) & 8); /* REX.R */ + index_reg = (ctxt->rex_prefix << 2) & 8; /* REX.X */ + base_reg = (ctxt->rex_prefix << 3) & 8; /* REX.B */ - ctxt->modrm_mod |= (ctxt->modrm & 0xc0) >> 6; + ctxt->modrm_mod = (ctxt->modrm & 0xc0) >> 6; ctxt->modrm_reg |= (ctxt->modrm & 0x38) >> 3; - ctxt->modrm_rm |= (ctxt->modrm & 0x07); + ctxt->modrm_rm = base_reg | (ctxt->modrm & 0x07); ctxt->modrm_seg = VCPU_SREG_DS; if (ctxt->modrm_mod == 3 || (ctxt->d & NoMod)) {