From 4179bb02fd3e87183e5f698495dfcb80df187889 Mon Sep 17 00:00:00 2001 From: Takuya Yoshikawa Date: Wed, 13 Apr 2011 00:29:09 +0900 Subject: [PATCH] KVM: x86 emulator: Make emulate_push() store the value directly PUSH emulation stores the value by calling writeback() after setting the dst operand appropriately in emulate_push(). This writeback() using dst is not needed at all because we know the target is the stack. So this patch makes emulate_push() call, newly introduced, segmented_write() directly. By this, many inlined writeback()'s are removed. Signed-off-by: Takuya Yoshikawa Signed-off-by: Avi Kivity --- arch/x86/kvm/emulate.c | 87 ++++++++++++++++++++------------------------------ 1 file changed, 34 insertions(+), 53 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 1e0e3f8..4f4d9bc 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1345,17 +1345,19 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt, return X86EMUL_CONTINUE; } -static inline void emulate_push(struct x86_emulate_ctxt *ctxt, - struct x86_emulate_ops *ops) +static int emulate_push(struct x86_emulate_ctxt *ctxt, + struct x86_emulate_ops *ops) { struct decode_cache *c = &ctxt->decode; + struct segmented_address addr; - c->dst.type = OP_MEM; - c->dst.bytes = c->op_bytes; - c->dst.val = c->src.val; register_address_increment(c, &c->regs[VCPU_REGS_RSP], -c->op_bytes); - c->dst.addr.mem.ea = register_address(c, c->regs[VCPU_REGS_RSP]); - c->dst.addr.mem.seg = VCPU_SREG_SS; + addr.ea = register_address(c, c->regs[VCPU_REGS_RSP]); + addr.seg = VCPU_SREG_SS; + + /* Disable writeback. */ + c->dst.type = OP_NONE; + return segmented_write(ctxt, addr, &c->src.val, c->op_bytes); } static int emulate_pop(struct x86_emulate_ctxt *ctxt, @@ -1417,14 +1419,14 @@ static int emulate_popf(struct x86_emulate_ctxt *ctxt, return rc; } -static void emulate_push_sreg(struct x86_emulate_ctxt *ctxt, - struct x86_emulate_ops *ops, int seg) +static int emulate_push_sreg(struct x86_emulate_ctxt *ctxt, + struct x86_emulate_ops *ops, int seg) { struct decode_cache *c = &ctxt->decode; c->src.val = ops->get_segment_selector(seg, ctxt->vcpu); - emulate_push(ctxt, ops); + return emulate_push(ctxt, ops); } static int emulate_pop_sreg(struct x86_emulate_ctxt *ctxt, @@ -1454,18 +1456,13 @@ static int emulate_pusha(struct x86_emulate_ctxt *ctxt, (reg == VCPU_REGS_RSP) ? (c->src.val = old_esp) : (c->src.val = c->regs[reg]); - emulate_push(ctxt, ops); - - rc = writeback(ctxt, ops); + rc = emulate_push(ctxt, ops); if (rc != X86EMUL_CONTINUE) return rc; ++reg; } - /* Disable writeback. */ - c->dst.type = OP_NONE; - return rc; } @@ -1503,27 +1500,22 @@ int emulate_int_real(struct x86_emulate_ctxt *ctxt, /* TODO: Add limit checks */ c->src.val = ctxt->eflags; - emulate_push(ctxt, ops); - rc = writeback(ctxt, ops); + rc = emulate_push(ctxt, ops); if (rc != X86EMUL_CONTINUE) return rc; ctxt->eflags &= ~(EFLG_IF | EFLG_TF | EFLG_AC); c->src.val = ops->get_segment_selector(VCPU_SREG_CS, ctxt->vcpu); - emulate_push(ctxt, ops); - rc = writeback(ctxt, ops); + rc = emulate_push(ctxt, ops); if (rc != X86EMUL_CONTINUE) return rc; c->src.val = c->eip; - emulate_push(ctxt, ops); - rc = writeback(ctxt, ops); + rc = emulate_push(ctxt, ops); if (rc != X86EMUL_CONTINUE) return rc; - c->dst.type = OP_NONE; - ops->get_idt(&dt, ctxt->vcpu); eip_addr = dt.address + (irq << 2); @@ -1713,6 +1705,7 @@ static inline int emulate_grp45(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) { struct decode_cache *c = &ctxt->decode; + int rc = X86EMUL_CONTINUE; switch (c->modrm_reg) { case 0: /* inc */ @@ -1726,17 +1719,17 @@ static inline int emulate_grp45(struct x86_emulate_ctxt *ctxt, old_eip = c->eip; c->eip = c->src.val; c->src.val = old_eip; - emulate_push(ctxt, ops); + rc = emulate_push(ctxt, ops); break; } case 4: /* jmp abs */ c->eip = c->src.val; break; case 6: /* push */ - emulate_push(ctxt, ops); + rc = emulate_push(ctxt, ops); break; } - return X86EMUL_CONTINUE; + return rc; } static inline int emulate_grp9(struct x86_emulate_ctxt *ctxt, @@ -2380,7 +2373,7 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt, c->op_bytes = c->ad_bytes = (next_tss_desc.type & 8) ? 4 : 2; c->lock_prefix = 0; c->src.val = (unsigned long) error_code; - emulate_push(ctxt, ops); + ret = emulate_push(ctxt, ops); } return ret; @@ -2400,11 +2393,8 @@ int emulator_task_switch(struct x86_emulate_ctxt *ctxt, rc = emulator_do_task_switch(ctxt, ops, tss_selector, reason, has_error_code, error_code); - if (rc == X86EMUL_CONTINUE) { - rc = writeback(ctxt, ops); - if (rc == X86EMUL_CONTINUE) - ctxt->eip = c->eip; - } + if (rc == X86EMUL_CONTINUE) + ctxt->eip = c->eip; return (rc == X86EMUL_UNHANDLEABLE) ? EMULATION_FAILED : EMULATION_OK; } @@ -2422,8 +2412,7 @@ static void string_addr_inc(struct x86_emulate_ctxt *ctxt, unsigned seg, static int em_push(struct x86_emulate_ctxt *ctxt) { - emulate_push(ctxt, ctxt->ops); - return X86EMUL_CONTINUE; + return emulate_push(ctxt, ctxt->ops); } static int em_das(struct x86_emulate_ctxt *ctxt) @@ -2483,20 +2472,12 @@ static int em_call_far(struct x86_emulate_ctxt *ctxt) memcpy(&c->eip, c->src.valptr, c->op_bytes); c->src.val = old_cs; - emulate_push(ctxt, ctxt->ops); - rc = writeback(ctxt, ctxt->ops); + rc = emulate_push(ctxt, ctxt->ops); if (rc != X86EMUL_CONTINUE) return rc; c->src.val = old_eip; - emulate_push(ctxt, ctxt->ops); - rc = writeback(ctxt, ctxt->ops); - if (rc != X86EMUL_CONTINUE) - return rc; - - c->dst.type = OP_NONE; - - return X86EMUL_CONTINUE; + return emulate_push(ctxt, ctxt->ops); } static int em_ret_near_imm(struct x86_emulate_ctxt *ctxt) @@ -3625,7 +3606,7 @@ special_insn: emulate_2op_SrcV("add", c->src, c->dst, ctxt->eflags); break; case 0x06: /* push es */ - emulate_push_sreg(ctxt, ops, VCPU_SREG_ES); + rc = emulate_push_sreg(ctxt, ops, VCPU_SREG_ES); break; case 0x07: /* pop es */ rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_ES); @@ -3635,14 +3616,14 @@ special_insn: emulate_2op_SrcV("or", c->src, c->dst, ctxt->eflags); break; case 0x0e: /* push cs */ - emulate_push_sreg(ctxt, ops, VCPU_SREG_CS); + rc = emulate_push_sreg(ctxt, ops, VCPU_SREG_CS); break; case 0x10 ... 0x15: adc: /* adc */ emulate_2op_SrcV("adc", c->src, c->dst, ctxt->eflags); break; case 0x16: /* push ss */ - emulate_push_sreg(ctxt, ops, VCPU_SREG_SS); + rc = emulate_push_sreg(ctxt, ops, VCPU_SREG_SS); break; case 0x17: /* pop ss */ rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_SS); @@ -3652,7 +3633,7 @@ special_insn: emulate_2op_SrcV("sbb", c->src, c->dst, ctxt->eflags); break; case 0x1e: /* push ds */ - emulate_push_sreg(ctxt, ops, VCPU_SREG_DS); + rc = emulate_push_sreg(ctxt, ops, VCPU_SREG_DS); break; case 0x1f: /* pop ds */ rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_DS); @@ -3789,7 +3770,7 @@ special_insn: break; case 0x9c: /* pushf */ c->src.val = (unsigned long) ctxt->eflags; - emulate_push(ctxt, ops); + rc = emulate_push(ctxt, ops); break; case 0x9d: /* popf */ c->dst.type = OP_REG; @@ -3864,7 +3845,7 @@ special_insn: long int rel = c->src.val; c->src.val = (unsigned long) c->eip; jmp_rel(c, rel); - emulate_push(ctxt, ops); + rc = emulate_push(ctxt, ops); break; } case 0xe9: /* jmp rel */ @@ -4157,7 +4138,7 @@ twobyte_insn: c->dst.val = test_cc(c->b, ctxt->eflags); break; case 0xa0: /* push fs */ - emulate_push_sreg(ctxt, ops, VCPU_SREG_FS); + rc = emulate_push_sreg(ctxt, ops, VCPU_SREG_FS); break; case 0xa1: /* pop fs */ rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_FS); @@ -4174,7 +4155,7 @@ twobyte_insn: emulate_2op_cl("shld", c->src2, c->src, c->dst, ctxt->eflags); break; case 0xa8: /* push gs */ - emulate_push_sreg(ctxt, ops, VCPU_SREG_GS); + rc = emulate_push_sreg(ctxt, ops, VCPU_SREG_GS); break; case 0xa9: /* pop gs */ rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_GS); -- 2.7.4