KVM: x86 emulator: do not inject exception directly into vcpu

Return exception as a result of instruction emulation and handle
injection in KVM code.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index a87d95f..51cfd73 100644 (file)
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -216,6 +216,12 @@ struct x86_emulate_ctxt {
        int interruptibility;
 
        bool restart; /* restart string instruction after writeback */
+
+       int exception; /* exception that happens during emulation or -1 */
+       u32 error_code; /* error code for exception */
+       bool error_code_valid;
+       unsigned long cr2; /* faulted address in case of #PF */
+
        /* decode cache */
        struct decode_cache decode;
 };

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index c40b405..b43ac98 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -653,6 +653,37 @@ static unsigned long ss_base(struct x86_emulate_ctxt *ctxt,
        return seg_base(ctxt, ops, VCPU_SREG_SS);
 }
 
+static void emulate_exception(struct x86_emulate_ctxt *ctxt, int vec,
+                                     u32 error, bool valid)
+{
+       ctxt->exception = vec;
+       ctxt->error_code = error;
+       ctxt->error_code_valid = valid;
+       ctxt->restart = false;
+}
+
+static void emulate_gp(struct x86_emulate_ctxt *ctxt, int err)
+{
+       emulate_exception(ctxt, GP_VECTOR, err, true);
+}
+
+static void emulate_pf(struct x86_emulate_ctxt *ctxt, unsigned long addr,
+                      int err)
+{
+       ctxt->cr2 = addr;
+       emulate_exception(ctxt, PF_VECTOR, err, true);
+}
+
+static void emulate_ud(struct x86_emulate_ctxt *ctxt)
+{
+       emulate_exception(ctxt, UD_VECTOR, 0, false);
+}
+
+static void emulate_ts(struct x86_emulate_ctxt *ctxt, int err)
+{
+       emulate_exception(ctxt, TS_VECTOR, err, true);
+}
+
 static int do_fetch_insn_byte(struct x86_emulate_ctxt *ctxt,
                              struct x86_emulate_ops *ops,
                              unsigned long eip, u8 *dest)
@@ -1285,7 +1316,7 @@ static int read_emulated(struct x86_emulate_ctxt *ctxt,
                rc = ops->read_emulated(addr, mc->data + mc->end, n, &err,
                                        ctxt->vcpu);
                if (rc == X86EMUL_PROPAGATE_FAULT)
-                       kvm_inject_page_fault(ctxt->vcpu, addr, err);
+                       emulate_pf(ctxt, addr, err);
                if (rc != X86EMUL_CONTINUE)
                        return rc;
                mc->end += n;
@@ -1366,13 +1397,13 @@ static int read_segment_descriptor(struct x86_emulate_ctxt *ctxt,
        get_descriptor_table_ptr(ctxt, ops, selector, &dt);
 
        if (dt.size < index * 8 + 7) {
-               kvm_inject_gp(ctxt->vcpu, selector & 0xfffc);
+               emulate_gp(ctxt, selector & 0xfffc);
                return X86EMUL_PROPAGATE_FAULT;
        }
        addr = dt.address + index * 8;
        ret = ops->read_std(addr, desc, sizeof *desc, ctxt->vcpu,  &err);
        if (ret == X86EMUL_PROPAGATE_FAULT)
-               kvm_inject_page_fault(ctxt->vcpu, addr, err);
+               emulate_pf(ctxt, addr, err);
 
        return ret;
 }
@@ -1391,14 +1422,14 @@ static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt,
        get_descriptor_table_ptr(ctxt, ops, selector, &dt);
 
        if (dt.size < index * 8 + 7) {
-               kvm_inject_gp(ctxt->vcpu, selector & 0xfffc);
+               emulate_gp(ctxt, selector & 0xfffc);
                return X86EMUL_PROPAGATE_FAULT;
        }
 
        addr = dt.address + index * 8;
        ret = ops->write_std(addr, desc, sizeof *desc, ctxt->vcpu, &err);
        if (ret == X86EMUL_PROPAGATE_FAULT)
-               kvm_inject_page_fault(ctxt->vcpu, addr, err);
+               emulate_pf(ctxt, addr, err);
 
        return ret;
 }
@@ -1517,7 +1548,7 @@ load:
        ops->set_cached_descriptor(&seg_desc, seg, ctxt->vcpu);
        return X86EMUL_CONTINUE;
 exception:
-       kvm_queue_exception_e(ctxt->vcpu, err_vec, err_code);
+       emulate_exception(ctxt, err_vec, err_code, true);
        return X86EMUL_PROPAGATE_FAULT;
 }
 
@@ -1578,7 +1609,7 @@ static int emulate_popf(struct x86_emulate_ctxt *ctxt,
                break;
        case X86EMUL_MODE_VM86:
                if (iopl < 3) {
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                        return X86EMUL_PROPAGATE_FAULT;
                }
                change_mask |= EFLG_IF;
@@ -1829,7 +1860,7 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt,
                                        &err,
                                        ctxt->vcpu);
                if (rc == X86EMUL_PROPAGATE_FAULT)
-                       kvm_inject_page_fault(ctxt->vcpu,
+                       emulate_pf(ctxt,
                                              (unsigned long)c->dst.ptr, err);
                if (rc != X86EMUL_CONTINUE)
                        return rc;
@@ -1883,7 +1914,7 @@ emulate_syscall(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
        /* syscall is not available in real mode */
        if (ctxt->mode == X86EMUL_MODE_REAL ||
            ctxt->mode == X86EMUL_MODE_VM86) {
-               kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+               emulate_ud(ctxt);
                return X86EMUL_PROPAGATE_FAULT;
        }
 
@@ -1937,7 +1968,7 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 
        /* inject #GP if in real mode */
        if (ctxt->mode == X86EMUL_MODE_REAL) {
-               kvm_inject_gp(ctxt->vcpu, 0);
+               emulate_gp(ctxt, 0);
                return X86EMUL_PROPAGATE_FAULT;
        }
 
@@ -1945,7 +1976,7 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
        * Therefore, we inject an #UD.
        */
        if (ctxt->mode == X86EMUL_MODE_PROT64) {
-               kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+               emulate_ud(ctxt);
                return X86EMUL_PROPAGATE_FAULT;
        }
 
@@ -1955,13 +1986,13 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
        switch (ctxt->mode) {
        case X86EMUL_MODE_PROT32:
                if ((msr_data & 0xfffc) == 0x0) {
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                        return X86EMUL_PROPAGATE_FAULT;
                }
                break;
        case X86EMUL_MODE_PROT64:
                if (msr_data == 0x0) {
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                        return X86EMUL_PROPAGATE_FAULT;
                }
                break;
@@ -2004,7 +2035,7 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
        /* inject #GP if in real mode or Virtual 8086 mode */
        if (ctxt->mode == X86EMUL_MODE_REAL ||
            ctxt->mode == X86EMUL_MODE_VM86) {
-               kvm_inject_gp(ctxt->vcpu, 0);
+               emulate_gp(ctxt, 0);
                return X86EMUL_PROPAGATE_FAULT;
        }
 
@@ -2022,7 +2053,7 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
        case X86EMUL_MODE_PROT32:
                cs_sel = (u16)(msr_data + 16);
                if ((msr_data & 0xfffc) == 0x0) {
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                        return X86EMUL_PROPAGATE_FAULT;
                }
                ss_sel = (u16)(msr_data + 24);
@@ -2030,7 +2061,7 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
        case X86EMUL_MODE_PROT64:
                cs_sel = (u16)(msr_data + 32);
                if (msr_data == 0x0) {
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                        return X86EMUL_PROPAGATE_FAULT;
                }
                ss_sel = cs_sel + 8;
@@ -2192,7 +2223,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
                            &err);
        if (ret == X86EMUL_PROPAGATE_FAULT) {
                /* FIXME: need to provide precise fault address */
-               kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
+               emulate_pf(ctxt, old_tss_base, err);
                return ret;
        }
 
@@ -2202,7 +2233,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
                             &err);
        if (ret == X86EMUL_PROPAGATE_FAULT) {
                /* FIXME: need to provide precise fault address */
-               kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
+               emulate_pf(ctxt, old_tss_base, err);
                return ret;
        }
 
@@ -2210,7 +2241,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
                            &err);
        if (ret == X86EMUL_PROPAGATE_FAULT) {
                /* FIXME: need to provide precise fault address */
-               kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
+               emulate_pf(ctxt, new_tss_base, err);
                return ret;
        }
 
@@ -2223,7 +2254,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
                                     ctxt->vcpu, &err);
                if (ret == X86EMUL_PROPAGATE_FAULT) {
                        /* FIXME: need to provide precise fault address */
-                       kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
+                       emulate_pf(ctxt, new_tss_base, err);
                        return ret;
                }
        }
@@ -2266,7 +2297,7 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt,
        int ret;
 
        if (ops->set_cr(3, tss->cr3, ctxt->vcpu)) {
-               kvm_inject_gp(ctxt->vcpu, 0);
+               emulate_gp(ctxt, 0);
                return X86EMUL_PROPAGATE_FAULT;
        }
        c->eip = tss->eip;
@@ -2334,7 +2365,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
                            &err);
        if (ret == X86EMUL_PROPAGATE_FAULT) {
                /* FIXME: need to provide precise fault address */
-               kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
+               emulate_pf(ctxt, old_tss_base, err);
                return ret;
        }
 
@@ -2344,7 +2375,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
                             &err);
        if (ret == X86EMUL_PROPAGATE_FAULT) {
                /* FIXME: need to provide precise fault address */
-               kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
+               emulate_pf(ctxt, old_tss_base, err);
                return ret;
        }
 
@@ -2352,7 +2383,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
                            &err);
        if (ret == X86EMUL_PROPAGATE_FAULT) {
                /* FIXME: need to provide precise fault address */
-               kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
+               emulate_pf(ctxt, new_tss_base, err);
                return ret;
        }
 
@@ -2365,7 +2396,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
                                     ctxt->vcpu, &err);
                if (ret == X86EMUL_PROPAGATE_FAULT) {
                        /* FIXME: need to provide precise fault address */
-                       kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
+                       emulate_pf(ctxt, new_tss_base, err);
                        return ret;
                }
        }
@@ -2399,7 +2430,7 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
        if (reason != TASK_SWITCH_IRET) {
                if ((tss_selector & 3) > next_tss_desc.dpl ||
                    ops->cpl(ctxt->vcpu) > next_tss_desc.dpl) {
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                        return X86EMUL_PROPAGATE_FAULT;
                }
        }
@@ -2408,8 +2439,7 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
        if (!next_tss_desc.p ||
            ((desc_limit < 0x67 && (next_tss_desc.type & 8)) ||
             desc_limit < 0x2b)) {
-               kvm_queue_exception_e(ctxt->vcpu, TS_VECTOR,
-                                     tss_selector & 0xfffc);
+               emulate_ts(ctxt, tss_selector & 0xfffc);
                return X86EMUL_PROPAGATE_FAULT;
        }
 
@@ -2505,19 +2535,19 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
        ctxt->decode.mem_read.pos = 0;
 
        if (ctxt->mode == X86EMUL_MODE_PROT64 && (c->d & No64)) {
-               kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+               emulate_ud(ctxt);
                goto done;
        }
 
        /* LOCK prefix is allowed only with some instructions */
        if (c->lock_prefix && (!(c->d & Lock) || c->dst.type != OP_MEM)) {
-               kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+               emulate_ud(ctxt);
                goto done;
        }
 
        /* Privileged instruction can be executed only in CPL=0 */
        if ((c->d & Priv) && ops->cpl(ctxt->vcpu)) {
-               kvm_inject_gp(ctxt->vcpu, 0);
+               emulate_gp(ctxt, 0);
                goto done;
        }
 
@@ -2679,7 +2709,7 @@ special_insn:
                c->dst.bytes = min(c->dst.bytes, 4u);
                if (!emulator_io_permited(ctxt, ops, c->regs[VCPU_REGS_RDX],
                                          c->dst.bytes)) {
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                        goto done;
                }
                if (!pio_in_emulated(ctxt, ops, c->dst.bytes,
@@ -2691,7 +2721,7 @@ special_insn:
                c->src.bytes = min(c->src.bytes, 4u);
                if (!emulator_io_permited(ctxt, ops, c->regs[VCPU_REGS_RDX],
                                          c->src.bytes)) {
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                        goto done;
                }
                ops->pio_out_emulated(c->src.bytes, c->regs[VCPU_REGS_RDX],
@@ -2754,7 +2784,7 @@ special_insn:
                goto mov;
        case 0x8c:  /* mov r/m, sreg */
                if (c->modrm_reg > VCPU_SREG_GS) {
-                       kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                       emulate_ud(ctxt);
                        goto done;
                }
                c->dst.val = ops->get_segment_selector(c->modrm_reg, ctxt->vcpu);
@@ -2769,7 +2799,7 @@ special_insn:
 
                if (c->modrm_reg == VCPU_SREG_CS ||
                    c->modrm_reg > VCPU_SREG_GS) {
-                       kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                       emulate_ud(ctxt);
                        goto done;
                }
 
@@ -2895,7 +2925,7 @@ special_insn:
        do_io_in:
                c->dst.bytes = min(c->dst.bytes, 4u);
                if (!emulator_io_permited(ctxt, ops, c->src.val, c->dst.bytes)) {
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                        goto done;
                }
                if (!pio_in_emulated(ctxt, ops, c->dst.bytes, c->src.val,
@@ -2908,7 +2938,7 @@ special_insn:
        do_io_out:
                c->dst.bytes = min(c->dst.bytes, 4u);
                if (!emulator_io_permited(ctxt, ops, c->src.val, c->dst.bytes)) {
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                        goto done;
                }
                ops->pio_out_emulated(c->dst.bytes, c->src.val, &c->dst.val, 1,
@@ -2933,7 +2963,7 @@ special_insn:
                break;
        case 0xfa: /* cli */
                if (emulator_bad_iopl(ctxt, ops))
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                else {
                        ctxt->eflags &= ~X86_EFLAGS_IF;
                        c->dst.type = OP_NONE;  /* Disable writeback. */
@@ -2941,7 +2971,7 @@ special_insn:
                break;
        case 0xfb: /* sti */
                if (emulator_bad_iopl(ctxt, ops))
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                else {
                        ctxt->interruptibility = KVM_X86_SHADOW_INT_STI;
                        ctxt->eflags |= X86_EFLAGS_IF;
@@ -3069,7 +3099,7 @@ twobyte_insn:
                        c->dst.type = OP_NONE;
                        break;
                case 5: /* not defined */
-                       kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                       emulate_ud(ctxt);
                        goto done;
                case 7: /* invlpg*/
                        emulate_invlpg(ctxt->vcpu, c->modrm_ea);
@@ -3102,7 +3132,7 @@ twobyte_insn:
                case 1:
                case 5 ... 7:
                case 9 ... 15:
-                       kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                       emulate_ud(ctxt);
                        goto done;
                }
                c->regs[c->modrm_rm] = ops->get_cr(c->modrm_reg, ctxt->vcpu);
@@ -3111,7 +3141,7 @@ twobyte_insn:
        case 0x21: /* mov from dr to reg */
                if ((ops->get_cr(4, ctxt->vcpu) & X86_CR4_DE) &&
                    (c->modrm_reg == 4 || c->modrm_reg == 5)) {
-                       kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                       emulate_ud(ctxt);
                        goto done;
                }
                ops->get_dr(c->modrm_reg, &c->regs[c->modrm_rm], ctxt->vcpu);
@@ -3119,7 +3149,7 @@ twobyte_insn:
                break;
        case 0x22: /* mov reg, cr */
                if (ops->set_cr(c->modrm_reg, c->modrm_val, ctxt->vcpu)) {
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                        goto done;
                }
                c->dst.type = OP_NONE;
@@ -3127,7 +3157,7 @@ twobyte_insn:
        case 0x23: /* mov from reg to dr */
                if ((ops->get_cr(4, ctxt->vcpu) & X86_CR4_DE) &&
                    (c->modrm_reg == 4 || c->modrm_reg == 5)) {
-                       kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                       emulate_ud(ctxt);
                        goto done;
                }
 
@@ -3135,7 +3165,7 @@ twobyte_insn:
                                ((ctxt->mode == X86EMUL_MODE_PROT64) ?
                                 ~0ULL : ~0U), ctxt->vcpu) < 0) {
                        /* #UD condition is already handled by the code above */
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                        goto done;
                }
 
@@ -3146,7 +3176,7 @@ twobyte_insn:
                msr_data = (u32)c->regs[VCPU_REGS_RAX]
                        | ((u64)c->regs[VCPU_REGS_RDX] << 32);
                if (ops->set_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], msr_data)) {
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                        goto done;
                }
                rc = X86EMUL_CONTINUE;
@@ -3155,7 +3185,7 @@ twobyte_insn:
        case 0x32:
                /* rdmsr */
                if (ops->get_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], &msr_data)) {
-                       kvm_inject_gp(ctxt->vcpu, 0);
+                       emulate_gp(ctxt, 0);
                        goto done;
                } else {
                        c->regs[VCPU_REGS_RAX] = (u32)msr_data;

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 91bfe77..63c87ad 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3852,6 +3852,17 @@ static void toggle_interruptibility(struct kvm_vcpu *vcpu, u32 mask)
                kvm_x86_ops->set_interrupt_shadow(vcpu, mask);
 }
 
+static void inject_emulated_exception(struct kvm_vcpu *vcpu)
+{
+       struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
+       if (ctxt->exception == PF_VECTOR)
+               kvm_inject_page_fault(vcpu, ctxt->cr2, ctxt->error_code);
+       else if (ctxt->error_code_valid)
+               kvm_queue_exception_e(vcpu, ctxt->exception, ctxt->error_code);
+       else
+               kvm_queue_exception(vcpu, ctxt->exception);
+}
+
 int emulate_instruction(struct kvm_vcpu *vcpu,
                        unsigned long cr2,
                        u16 error_code,
@@ -3886,6 +3897,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
                memset(c, 0, sizeof(struct decode_cache));
                memcpy(c->regs, vcpu->arch.regs, sizeof c->regs);
                vcpu->arch.emulate_ctxt.interruptibility = 0;
+               vcpu->arch.emulate_ctxt.exception = -1;
 
                r = x86_decode_insn(&vcpu->arch.emulate_ctxt, &emulate_ops);
                trace_kvm_emulate_insn_start(vcpu);
@@ -3958,6 +3970,11 @@ restart:
        memcpy(vcpu->arch.regs, c->regs, sizeof c->regs);
        kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip);
 
+       if (vcpu->arch.emulate_ctxt.exception >= 0) {
+               inject_emulated_exception(vcpu);
+               return EMULATE_DONE;
+       }
+
        if (vcpu->arch.pio.count) {
                if (!vcpu->arch.pio.in)
                        vcpu->arch.pio.count = 0;
@@ -3970,9 +3987,6 @@ restart:
                return EMULATE_DO_MMIO;
        }
 
-       if (vcpu->arch.exception.pending)
-               vcpu->arch.emulate_ctxt.restart = false;
-
        if (vcpu->arch.emulate_ctxt.restart)
                goto restart;