From a01af5ec5163cdc51c00f6dcb22d7766199377cf Mon Sep 17 00:00:00 2001 From: Laurent Vivier Date: Mon, 24 Sep 2007 11:10:56 +0200 Subject: [PATCH] KVM: x86 emulator: Remove no_wb, use dst.type = OP_NONE instead Remove no_wb, use dst.type = OP_NONE instead, idea stollen from xen-3.1 Signed-off-by: Laurent Vivier Signed-off-by: Avi Kivity --- drivers/kvm/x86_emulate.c | 76 +++++++++++++-------------------------- drivers/kvm/x86_emulate.h | 2 +- 2 files changed, 25 insertions(+), 53 deletions(-) diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c index 76b813b636..6161e3f665 100644 --- a/drivers/kvm/x86_emulate.c +++ b/drivers/kvm/x86_emulate.c @@ -1016,8 +1016,7 @@ done: } static inline int emulate_grp45(struct x86_emulate_ctxt *ctxt, - struct x86_emulate_ops *ops, - int *no_wb) + struct x86_emulate_ops *ops) { struct decode_cache *c = &ctxt->decode; int rc; @@ -1055,7 +1054,7 @@ static inline int emulate_grp45(struct x86_emulate_ctxt *ctxt, c->dst.bytes, ctxt->vcpu); if (rc != 0) return rc; - *no_wb = 1; + c->dst.type = OP_NONE; break; default: DPRINTF("Cannot emulate %02x\n", c->b); @@ -1137,6 +1136,10 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt, ctxt->vcpu); if (rc != 0) return rc; + break; + case OP_NONE: + /* no writeback */ + break; default: break; } @@ -1147,7 +1150,6 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) { unsigned long cr2 = ctxt->cr2; - int no_wb = 0; u64 msr_data; unsigned long saved_eip = 0; struct decode_cache *c = &ctxt->decode; @@ -1344,18 +1346,16 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) goto done; break; case 0xfe ... 0xff: /* Grp4/Grp5 */ - rc = emulate_grp45(ctxt, ops, &no_wb); + rc = emulate_grp45(ctxt, ops); if (rc != 0) goto done; break; } writeback: - if (!no_wb) { - rc = writeback(ctxt, ops); - if (rc != 0) - goto done; - } + rc = writeback(ctxt, ops); + if (rc != 0) + goto done; /* Commit shadow register state. */ memcpy(ctxt->vcpu->regs, c->regs, sizeof c->regs); @@ -1395,7 +1395,7 @@ special_insn: register_address_increment(c->regs[VCPU_REGS_RSP], c->op_bytes); - no_wb = 1; /* Disable writeback. */ + c->dst.type = OP_NONE; /* Disable writeback. */ break; case 0x6a: /* push imm8 */ c->src.val = 0L; @@ -1538,7 +1538,7 @@ special_insn: case 0xe9: /* jmp rel */ case 0xeb: /* jmp rel short */ JMP_REL(c->src.val); - no_wb = 1; /* Disable writeback. */ + c->dst.type = OP_NONE; /* Disable writeback. */ break; @@ -1548,8 +1548,6 @@ special_insn: twobyte_insn: switch (c->b) { case 0x01: /* lgdt, lidt, lmsw */ - /* Disable writeback. */ - no_wb = 1; switch (c->modrm_reg) { u16 size; unsigned long address; @@ -1604,56 +1602,30 @@ twobyte_insn: default: goto cannot_emulate; } + /* Disable writeback. */ + c->dst.type = OP_NONE; break; case 0x21: /* mov from dr to reg */ - no_wb = 1; if (c->modrm_mod != 3) goto cannot_emulate; rc = emulator_get_dr(ctxt, c->modrm_reg, &c->regs[c->modrm_rm]); + if (rc) + goto cannot_emulate; + c->dst.type = OP_NONE; /* no writeback */ break; case 0x23: /* mov from reg to dr */ - no_wb = 1; if (c->modrm_mod != 3) goto cannot_emulate; rc = emulator_set_dr(ctxt, c->modrm_reg, c->regs[c->modrm_rm]); + if (rc) + goto cannot_emulate; + c->dst.type = OP_NONE; /* no writeback */ break; case 0x40 ... 0x4f: /* cmov */ c->dst.val = c->dst.orig_val = c->src.val; - no_wb = 1; - /* - * First, assume we're decoding an even cmov opcode - * (lsb == 0). - */ - switch ((c->b & 15) >> 1) { - case 0: /* cmovo */ - no_wb = (ctxt->eflags & EFLG_OF) ? 0 : 1; - break; - case 1: /* cmovb/cmovc/cmovnae */ - no_wb = (ctxt->eflags & EFLG_CF) ? 0 : 1; - break; - case 2: /* cmovz/cmove */ - no_wb = (ctxt->eflags & EFLG_ZF) ? 0 : 1; - break; - case 3: /* cmovbe/cmovna */ - no_wb = (ctxt->eflags & (EFLG_CF | EFLG_ZF)) ? 0 : 1; - break; - case 4: /* cmovs */ - no_wb = (ctxt->eflags & EFLG_SF) ? 0 : 1; - break; - case 5: /* cmovp/cmovpe */ - no_wb = (ctxt->eflags & EFLG_PF) ? 0 : 1; - break; - case 7: /* cmovle/cmovng */ - no_wb = (ctxt->eflags & EFLG_ZF) ? 0 : 1; - /* fall through */ - case 6: /* cmovl/cmovnge */ - no_wb &= (!(ctxt->eflags & EFLG_SF) != - !(ctxt->eflags & EFLG_OF)) ? 0 : 1; - break; - } - /* Odd cmov opcodes (lsb == 1) have inverted sense. */ - no_wb ^= c->b & 1; + if (!test_cc(c->b, ctxt->eflags)) + c->dst.type = OP_NONE; /* no writeback */ break; case 0xa3: bt: /* bt */ @@ -1727,8 +1699,6 @@ twobyte_insn: goto writeback; twobyte_special_insn: - /* Disable writeback. */ - no_wb = 1; switch (c->b) { case 0x06: emulate_clts(ctxt->vcpu); @@ -1802,6 +1772,8 @@ twobyte_special_insn: goto done; break; } + /* Disable writeback. */ + c->dst.type = OP_NONE; goto writeback; cannot_emulate: diff --git a/drivers/kvm/x86_emulate.h b/drivers/kvm/x86_emulate.h index 28acad416b..f03b128770 100644 --- a/drivers/kvm/x86_emulate.h +++ b/drivers/kvm/x86_emulate.h @@ -114,7 +114,7 @@ struct x86_emulate_ops { /* Type, address-of, and value of an instruction's operand. */ struct operand { - enum { OP_REG, OP_MEM, OP_IMM } type; + enum { OP_REG, OP_MEM, OP_IMM, OP_NONE } type; unsigned int bytes; unsigned long val, orig_val, *ptr; }; -- 2.39.5