From 7e11eec989c840ff8cd11cee5005c7ce68ef1ab3 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 13 Nov 2025 19:36:28 -0500 Subject: [PATCH] KVM: x86: Share emulator's common register decoding code Remove all duplicate handling of register operands, including picking the right register class and fetching it, by extracting a new function that can be used for both REG and MODRM operands. Centralize setting op->orig_val = op->val in fetch_register_operand() as well. No functional change intended. Signed-off-by: Paolo Bonzini Reviewed-by: Chang S. Bae Link: https://patch.msgid.link/20251114003633.60689-6-pbonzini@redhat.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/emulate.c | 49 +++++++++++++++--------------------------- 1 file changed, 17 insertions(+), 32 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 23019928734a6..8a755ef30c182 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1026,6 +1026,7 @@ static void fetch_register_operand(struct operand *op) op->val = *(u64 *)op->addr.reg; break; } + op->orig_val = op->val; } static int em_fninit(struct x86_emulate_ctxt *ctxt) @@ -1071,16 +1072,9 @@ static int em_fnstsw(struct x86_emulate_ctxt *ctxt) return X86EMUL_CONTINUE; } -static void decode_register_operand(struct x86_emulate_ctxt *ctxt, - struct operand *op) +static void __decode_register_operand(struct x86_emulate_ctxt *ctxt, + struct operand *op, int reg) { - unsigned int reg; - - if (ctxt->d & ModRM) - reg = ctxt->modrm_reg; - else - reg = (ctxt->b & 7) | ((ctxt->rex_prefix & 1) << 3); - if (ctxt->d & Sse) { op->type = OP_XMM; op->bytes = 16; @@ -1099,9 +1093,20 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt, op->type = OP_REG; op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes; op->addr.reg = decode_register(ctxt, reg, ctxt->d & ByteOp); - fetch_register_operand(op); - op->orig_val = op->val; +} + +static void decode_register_operand(struct x86_emulate_ctxt *ctxt, + struct operand *op) +{ + unsigned int reg; + + if (ctxt->d & ModRM) + reg = ctxt->modrm_reg; + else + reg = (ctxt->b & 7) | ((ctxt->rex_prefix & 1) << 3); + + __decode_register_operand(ctxt, op, reg); } static void adjust_modrm_seg(struct x86_emulate_ctxt *ctxt, int base_reg) @@ -1128,24 +1133,7 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt, ctxt->modrm_seg = VCPU_SREG_DS; if (ctxt->modrm_mod == 3 || (ctxt->d & NoMod)) { - op->type = OP_REG; - op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes; - op->addr.reg = decode_register(ctxt, ctxt->modrm_rm, - ctxt->d & ByteOp); - if (ctxt->d & Sse) { - op->type = OP_XMM; - op->bytes = 16; - op->addr.xmm = ctxt->modrm_rm; - kvm_read_sse_reg(ctxt->modrm_rm, &op->vec_val); - return rc; - } - if (ctxt->d & Mmx) { - op->type = OP_MM; - op->bytes = 8; - op->addr.mm = ctxt->modrm_rm & 7; - return rc; - } - fetch_register_operand(op); + __decode_register_operand(ctxt, op, ctxt->modrm_rm); return rc; } @@ -4619,14 +4607,12 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op, op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes; op->addr.reg = reg_rmw(ctxt, VCPU_REGS_RAX); fetch_register_operand(op); - op->orig_val = op->val; break; case OpAccLo: op->type = OP_REG; op->bytes = (ctxt->d & ByteOp) ? 2 : ctxt->op_bytes; op->addr.reg = reg_rmw(ctxt, VCPU_REGS_RAX); fetch_register_operand(op); - op->orig_val = op->val; break; case OpAccHi: if (ctxt->d & ByteOp) { @@ -4637,7 +4623,6 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op, op->bytes = ctxt->op_bytes; op->addr.reg = reg_rmw(ctxt, VCPU_REGS_RDX); fetch_register_operand(op); - op->orig_val = op->val; break; case OpDI: op->type = OP_MEM; -- 2.47.3