1 files changed, 186 insertions, 64 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index a46207a05835..749f9fa38254 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -504,11 +504,6 @@ static void rsp_increment(struct x86_emulate_ctxt *ctxt, int inc)
         masked_increment(reg_rmw(ctxt, VCPU_REGS_RSP), stack_mask(ctxt), inc);
 }
 
-static inline void jmp_rel(struct x86_emulate_ctxt *ctxt, int rel)
-{
-        register_address_increment(ctxt, &ctxt->_eip, rel);
-}
-
 static u32 desc_limit_scaled(struct desc_struct *desc)
 {
         u32 limit = get_desc_limit(desc);
@@ -569,6 +564,38 @@ static int emulate_nm(struct x86_emulate_ctxt *ctxt)
         return emulate_exception(ctxt, NM_VECTOR, 0, false);
 }
 
+static inline int assign_eip_far(struct x86_emulate_ctxt *ctxt, ulong dst,
+                               int cs_l)
+{
+        switch (ctxt->op_bytes) {
+        case 2:
+                ctxt->_eip = (u16)dst;
+                break;
+        case 4:
+                ctxt->_eip = (u32)dst;
+                break;
+        case 8:
+                if ((cs_l && is_noncanonical_address(dst)) ||
+                    (!cs_l && (dst & ~(u32)-1)))
+                        return emulate_gp(ctxt, 0);
+                ctxt->_eip = dst;
+                break;
+        default:
+                WARN(1, "unsupported eip assignment size\n");
+        }
+        return X86EMUL_CONTINUE;
+}
+
+static inline int assign_eip_near(struct x86_emulate_ctxt *ctxt, ulong dst)
+{
+        return assign_eip_far(ctxt, dst, ctxt->mode == X86EMUL_MODE_PROT64);
+}
+
+static inline int jmp_rel(struct x86_emulate_ctxt *ctxt, int rel)
+{
+        return assign_eip_near(ctxt, ctxt->_eip + rel);
+}
+
 static u16 get_segment_selector(struct x86_emulate_ctxt *ctxt, unsigned seg)
 {
         u16 selector;
@@ -751,8 +778,10 @@ static int __do_insn_fetch_bytes(struct x86_emulate_ctxt *ctxt, int op_size)
 static __always_inline int do_insn_fetch_bytes(struct x86_emulate_ctxt *ctxt,
                                                unsigned size)
 {
-        if (unlikely(ctxt->fetch.end - ctxt->fetch.ptr < size))
-                return __do_insn_fetch_bytes(ctxt, size);
+        unsigned done_size = ctxt->fetch.end - ctxt->fetch.ptr;
+
+        if (unlikely(done_size < size))
+                return __do_insn_fetch_bytes(ctxt, size - done_size);
         else
                 return X86EMUL_CONTINUE;
 }
@@ -1416,7 +1445,9 @@ static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt,
 
 /* Does not support long mode */
 static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
-                                     u16 selector, int seg, u8 cpl, bool in_task_switch)
+                                     u16 selector, int seg, u8 cpl,
+                                     bool in_task_switch,
+                                     struct desc_struct *desc)
 {
         struct desc_struct seg_desc, old_desc;
         u8 dpl, rpl;
@@ -1557,6 +1588,8 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
         }
 load:
         ctxt->ops->set_segment(ctxt, selector, &seg_desc, base3, seg);
+        if (desc)
+                *desc = seg_desc;
         return X86EMUL_CONTINUE;
 exception:
         return emulate_exception(ctxt, err_vec, err_code, true);
@@ -1566,7 +1599,7 @@ static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
                                    u16 selector, int seg)
 {
         u8 cpl = ctxt->ops->cpl(ctxt);
-        return __load_segment_descriptor(ctxt, selector, seg, cpl, false);
+        return __load_segment_descriptor(ctxt, selector, seg, cpl, false, NULL);
 }
 
 static void write_register_operand(struct operand *op)
@@ -1960,17 +1993,31 @@ static int em_iret(struct x86_emulate_ctxt *ctxt)
 static int em_jmp_far(struct x86_emulate_ctxt *ctxt)
 {
         int rc;
-        unsigned short sel;
+        unsigned short sel, old_sel;
+        struct desc_struct old_desc, new_desc;
+        const struct x86_emulate_ops *ops = ctxt->ops;
+        u8 cpl = ctxt->ops->cpl(ctxt);
+
+        /* Assignment of RIP may only fail in 64-bit mode */
+        if (ctxt->mode == X86EMUL_MODE_PROT64)
+                ops->get_segment(ctxt, &old_sel, &old_desc, NULL,
+                                 VCPU_SREG_CS);
 
         memcpy(&sel, ctxt->src.valptr + ctxt->op_bytes, 2);
 
-        rc = load_segment_descriptor(ctxt, sel, VCPU_SREG_CS);
+        rc = __load_segment_descriptor(ctxt, sel, VCPU_SREG_CS, cpl, false,
+                                       &new_desc);
         if (rc != X86EMUL_CONTINUE)
                 return rc;
 
-        ctxt->_eip = 0;
-        memcpy(&ctxt->_eip, ctxt->src.valptr, ctxt->op_bytes);
-        return X86EMUL_CONTINUE;
+        rc = assign_eip_far(ctxt, ctxt->src.val, new_desc.l);
+        if (rc != X86EMUL_CONTINUE) {
+                WARN_ON(!ctxt->mode != X86EMUL_MODE_PROT64);
+                /* assigning eip failed; restore the old cs */
+                ops->set_segment(ctxt, old_sel, &old_desc, 0, VCPU_SREG_CS);
+                return rc;
+        }
+        return rc;
 }
 
 static int em_grp45(struct x86_emulate_ctxt *ctxt)
@@ -1981,13 +2028,15 @@ static int em_grp45(struct x86_emulate_ctxt *ctxt)
         case 2: /* call near abs */ {
                 long int old_eip;
                 old_eip = ctxt->_eip;
-                ctxt->_eip = ctxt->src.val;
+                rc = assign_eip_near(ctxt, ctxt->src.val);
+                if (rc != X86EMUL_CONTINUE)
+                        break;
                 ctxt->src.val = old_eip;
                 rc = em_push(ctxt);
                 break;
         }
         case 4: /* jmp abs */
-                ctxt->_eip = ctxt->src.val;
+                rc = assign_eip_near(ctxt, ctxt->src.val);
                 break;
         case 5: /* jmp far */
                 rc = em_jmp_far(ctxt);
@@ -2022,30 +2071,47 @@ static int em_cmpxchg8b(struct x86_emulate_ctxt *ctxt)
 
 static int em_ret(struct x86_emulate_ctxt *ctxt)
 {
-        ctxt->dst.type = OP_REG;
-        ctxt->dst.addr.reg = &ctxt->_eip;
-        ctxt->dst.bytes = ctxt->op_bytes;
-        return em_pop(ctxt);
+        int rc;
+        unsigned long eip;
+
+        rc = emulate_pop(ctxt, &eip, ctxt->op_bytes);
+        if (rc != X86EMUL_CONTINUE)
+                return rc;
+
+        return assign_eip_near(ctxt, eip);
 }
 
 static int em_ret_far(struct x86_emulate_ctxt *ctxt)
 {
         int rc;
-        unsigned long cs;
+        unsigned long eip, cs;
+        u16 old_cs;
         int cpl = ctxt->ops->cpl(ctxt);
+        struct desc_struct old_desc, new_desc;
+        const struct x86_emulate_ops *ops = ctxt->ops;
 
-        rc = emulate_pop(ctxt, &ctxt->_eip, ctxt->op_bytes);
+        if (ctxt->mode == X86EMUL_MODE_PROT64)
+                ops->get_segment(ctxt, &old_cs, &old_desc, NULL,
+                                 VCPU_SREG_CS);
+
+        rc = emulate_pop(ctxt, &eip, ctxt->op_bytes);
         if (rc != X86EMUL_CONTINUE)
                 return rc;
-        if (ctxt->op_bytes == 4)
-                ctxt->_eip = (u32)ctxt->_eip;
         rc = emulate_pop(ctxt, &cs, ctxt->op_bytes);
         if (rc != X86EMUL_CONTINUE)
                 return rc;
         /* Outer-privilege level return is not implemented */
         if (ctxt->mode >= X86EMUL_MODE_PROT16 && (cs & 3) > cpl)
                 return X86EMUL_UNHANDLEABLE;
-        rc = load_segment_descriptor(ctxt, (u16)cs, VCPU_SREG_CS);
+        rc = __load_segment_descriptor(ctxt, (u16)cs, VCPU_SREG_CS, 0, false,
+                                       &new_desc);
+        if (rc != X86EMUL_CONTINUE)
+                return rc;
+        rc = assign_eip_far(ctxt, eip, new_desc.l);
+        if (rc != X86EMUL_CONTINUE) {
+                WARN_ON(!ctxt->mode != X86EMUL_MODE_PROT64);
+                ops->set_segment(ctxt, old_cs, &old_desc, 0, VCPU_SREG_CS);
+        }
         return rc;
 }
 
@@ -2306,7 +2372,7 @@ static int em_sysexit(struct x86_emulate_ctxt *ctxt)
 {
         const struct x86_emulate_ops *ops = ctxt->ops;
         struct desc_struct cs, ss;
-        u64 msr_data;
+        u64 msr_data, rcx, rdx;
         int usermode;
         u16 cs_sel = 0, ss_sel = 0;
 
@@ -2322,6 +2388,9 @@ static int em_sysexit(struct x86_emulate_ctxt *ctxt)
         else
                 usermode = X86EMUL_MODE_PROT32;
 
+        rcx = reg_read(ctxt, VCPU_REGS_RCX);
+        rdx = reg_read(ctxt, VCPU_REGS_RDX);
+
         cs.dpl = 3;
         ss.dpl = 3;
         ops->get_msr(ctxt, MSR_IA32_SYSENTER_CS, &msr_data);
@@ -2339,6 +2408,9 @@ static int em_sysexit(struct x86_emulate_ctxt *ctxt)
                 ss_sel = cs_sel + 8;
                 cs.d = 0;
                 cs.l = 1;
+                if (is_noncanonical_address(rcx) ||
+                    is_noncanonical_address(rdx))
+                        return emulate_gp(ctxt, 0);
                 break;
         }
         cs_sel |= SELECTOR_RPL_MASK;
@@ -2347,8 +2419,8 @@ static int em_sysexit(struct x86_emulate_ctxt *ctxt)
         ops->set_segment(ctxt, cs_sel, &cs, 0, VCPU_SREG_CS);
         ops->set_segment(ctxt, ss_sel, &ss, 0, VCPU_SREG_SS);
 
-        ctxt->_eip = reg_read(ctxt, VCPU_REGS_RDX);
-        *reg_write(ctxt, VCPU_REGS_RSP) = reg_read(ctxt, VCPU_REGS_RCX);
+        ctxt->_eip = rdx;
+        *reg_write(ctxt, VCPU_REGS_RSP) = rcx;
 
         return X86EMUL_CONTINUE;
 }
@@ -2466,19 +2538,24 @@ static int load_state_from_tss16(struct x86_emulate_ctxt *ctxt,
          * Now load segment descriptors. If fault happens at this stage
          * it is handled in a context of new task
          */
-        ret = __load_segment_descriptor(ctxt, tss->ldt, VCPU_SREG_LDTR, cpl, true);
+        ret = __load_segment_descriptor(ctxt, tss->ldt, VCPU_SREG_LDTR, cpl,
+                                        true, NULL);
         if (ret != X86EMUL_CONTINUE)
                 return ret;
-        ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl, true);
+        ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl,
+                                        true, NULL);
         if (ret != X86EMUL_CONTINUE)
                 return ret;
-        ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl, true);
+        ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl,
+                                        true, NULL);
         if (ret != X86EMUL_CONTINUE)
                 return ret;
-        ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl, true);
+        ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl,
+                                        true, NULL);
         if (ret != X86EMUL_CONTINUE)
                 return ret;
-        ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl, true);
+        ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl,
+                                        true, NULL);
         if (ret != X86EMUL_CONTINUE)
                 return ret;
 
@@ -2603,25 +2680,32 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt,
          * Now load segment descriptors. If fault happenes at this stage
          * it is handled in a context of new task
          */
-        ret = __load_segment_descriptor(ctxt, tss->ldt_selector, VCPU_SREG_LDTR, cpl, true);
+        ret = __load_segment_descriptor(ctxt, tss->ldt_selector, VCPU_SREG_LDTR,
+                                        cpl, true, NULL);
         if (ret != X86EMUL_CONTINUE)
                 return ret;
-        ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl, true);
+        ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl,
+                                        true, NULL);
         if (ret != X86EMUL_CONTINUE)
                 return ret;
-        ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl, true);
+        ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl,
+                                        true, NULL);
         if (ret != X86EMUL_CONTINUE)
                 return ret;
-        ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl, true);
+        ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl,
+                                        true, NULL);
         if (ret != X86EMUL_CONTINUE)
                 return ret;
-        ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl, true);
+        ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl,
+                                        true, NULL);
         if (ret != X86EMUL_CONTINUE)
                 return ret;
-        ret = __load_segment_descriptor(ctxt, tss->fs, VCPU_SREG_FS, cpl, true);
+        ret = __load_segment_descriptor(ctxt, tss->fs, VCPU_SREG_FS, cpl,
+                                        true, NULL);
         if (ret != X86EMUL_CONTINUE)
                 return ret;
-        ret = __load_segment_descriptor(ctxt, tss->gs, VCPU_SREG_GS, cpl, true);
+        ret = __load_segment_descriptor(ctxt, tss->gs, VCPU_SREG_GS, cpl,
+                                        true, NULL);
         if (ret != X86EMUL_CONTINUE)
                 return ret;
 
@@ -2888,10 +2972,13 @@ static int em_aad(struct x86_emulate_ctxt *ctxt)
 
 static int em_call(struct x86_emulate_ctxt *ctxt)
 {
+        int rc;
         long rel = ctxt->src.val;
 
         ctxt->src.val = (unsigned long)ctxt->_eip;
-        jmp_rel(ctxt, rel);
+        rc = jmp_rel(ctxt, rel);
+        if (rc != X86EMUL_CONTINUE)
+                return rc;
         return em_push(ctxt);
 }
 
@@ -2900,34 +2987,50 @@ static int em_call_far(struct x86_emulate_ctxt *ctxt)
         u16 sel, old_cs;
         ulong old_eip;
         int rc;
+        struct desc_struct old_desc, new_desc;
+        const struct x86_emulate_ops *ops = ctxt->ops;
+        int cpl = ctxt->ops->cpl(ctxt);
 
-        old_cs = get_segment_selector(ctxt, VCPU_SREG_CS);
         old_eip = ctxt->_eip;
+        ops->get_segment(ctxt, &old_cs, &old_desc, NULL, VCPU_SREG_CS);
 
         memcpy(&sel, ctxt->src.valptr + ctxt->op_bytes, 2);
-        if (load_segment_descriptor(ctxt, sel, VCPU_SREG_CS))
+        rc = __load_segment_descriptor(ctxt, sel, VCPU_SREG_CS, cpl, false,
+                                       &new_desc);
+        if (rc != X86EMUL_CONTINUE)
                 return X86EMUL_CONTINUE;
 
-        ctxt->_eip = 0;
-        memcpy(&ctxt->_eip, ctxt->src.valptr, ctxt->op_bytes);
+        rc = assign_eip_far(ctxt, ctxt->src.val, new_desc.l);
+        if (rc != X86EMUL_CONTINUE)
+                goto fail;
 
         ctxt->src.val = old_cs;
         rc = em_push(ctxt);
         if (rc != X86EMUL_CONTINUE)
-                return rc;
+                goto fail;
 
         ctxt->src.val = old_eip;
-        return em_push(ctxt);
+        rc = em_push(ctxt);
+        /* If we failed, we tainted the memory, but the very least we should
+           restore cs */
+        if (rc != X86EMUL_CONTINUE)
+                goto fail;
+        return rc;
+fail:
+        ops->set_segment(ctxt, old_cs, &old_desc, 0, VCPU_SREG_CS);
+        return rc;
+
 }
 
 static int em_ret_near_imm(struct x86_emulate_ctxt *ctxt)
 {
         int rc;
+        unsigned long eip;
 
-        ctxt->dst.type = OP_REG;
-        ctxt->dst.addr.reg = &ctxt->_eip;
-        ctxt->dst.bytes = ctxt->op_bytes;
-        rc = emulate_pop(ctxt, &ctxt->dst.val, ctxt->op_bytes);
+        rc = emulate_pop(ctxt, &eip, ctxt->op_bytes);
+        if (rc != X86EMUL_CONTINUE)
+                return rc;
+        rc = assign_eip_near(ctxt, eip);
         if (rc != X86EMUL_CONTINUE)
                 return rc;
         rsp_increment(ctxt, ctxt->src.val);
@@ -3254,20 +3357,24 @@ static int em_lmsw(struct x86_emulate_ctxt *ctxt)
 
 static int em_loop(struct x86_emulate_ctxt *ctxt)
 {
+        int rc = X86EMUL_CONTINUE;
+
         register_address_increment(ctxt, reg_rmw(ctxt, VCPU_REGS_RCX), -1);
         if ((address_mask(ctxt, reg_read(ctxt, VCPU_REGS_RCX)) != 0) &&
             (ctxt->b == 0xe2 || test_cc(ctxt->b ^ 0x5, ctxt->eflags)))
-                jmp_rel(ctxt, ctxt->src.val);
+                rc = jmp_rel(ctxt, ctxt->src.val);
 
-        return X86EMUL_CONTINUE;
+        return rc;
 }
 
 static int em_jcxz(struct x86_emulate_ctxt *ctxt)
 {
+        int rc = X86EMUL_CONTINUE;
+
         if (address_mask(ctxt, reg_read(ctxt, VCPU_REGS_RCX)) == 0)
-                jmp_rel(ctxt, ctxt->src.val);
+                rc = jmp_rel(ctxt, ctxt->src.val);
 
-        return X86EMUL_CONTINUE;
+        return rc;
 }
 
 static int em_in(struct x86_emulate_ctxt *ctxt)
@@ -3355,6 +3462,12 @@ static int em_bswap(struct x86_emulate_ctxt *ctxt)
         return X86EMUL_CONTINUE;
 }
 
+static int em_clflush(struct x86_emulate_ctxt *ctxt)
+{
+        /* emulating clflush regardless of cpuid */
+        return X86EMUL_CONTINUE;
+}
+
 static bool valid_cr(int nr)
 {
         switch (nr) {
@@ -3693,6 +3806,16 @@ static const struct opcode group11[] = {
         X7(D(Undefined)),
 };
 
+static const struct gprefix pfx_0f_ae_7 = {
+        I(SrcMem | ByteOp, em_clflush), N, N, N,
+};
+
+static const struct group_dual group15 = { {
+        N, N, N, N, N, N, N, GP(0, &pfx_0f_ae_7),
+}, {
+        N, N, N, N, N, N, N, N,
+} };
+
 static const struct gprefix pfx_0f_6f_0f_7f = {
         I(Mmx, em_mov), I(Sse | Aligned, em_mov), N, I(Sse | Unaligned, em_mov),
 };
@@ -3901,10 +4024,11 @@ static const struct opcode twobyte_table[256] = {
         N, I(ImplicitOps | EmulateOnUD, em_syscall),
         II(ImplicitOps | Priv, em_clts, clts), N,
         DI(ImplicitOps | Priv, invd), DI(ImplicitOps | Priv, wbinvd), N, N,
-        N, D(ImplicitOps | ModRM), N, N,
+        N, D(ImplicitOps | ModRM | SrcMem | NoAccess), N, N,
         /* 0x10 - 0x1F */
         N, N, N, N, N, N, N, N,
-        D(ImplicitOps | ModRM), N, N, N, N, N, N, D(ImplicitOps | ModRM),
+        D(ImplicitOps | ModRM | SrcMem | NoAccess),
+        N, N, N, N, N, N, D(ImplicitOps | ModRM | SrcMem | NoAccess),
         /* 0x20 - 0x2F */
         DIP(ModRM | DstMem | Priv | Op3264 | NoMod, cr_read, check_cr_read),
         DIP(ModRM | DstMem | Priv | Op3264 | NoMod, dr_read, check_dr_read),
@@ -3956,7 +4080,7 @@ static const struct opcode twobyte_table[256] = {
         F(DstMem | SrcReg | ModRM | BitOp | Lock | PageTable, em_bts),
         F(DstMem | SrcReg | Src2ImmByte | ModRM, em_shrd),
         F(DstMem | SrcReg | Src2CL | ModRM, em_shrd),
-        D(ModRM), F(DstReg | SrcMem | ModRM, em_imul),
+        GD(0, &group15), F(DstReg | SrcMem | ModRM, em_imul),
         /* 0xB0 - 0xB7 */
         I2bv(DstMem | SrcReg | ModRM | Lock | PageTable, em_cmpxchg),
         I(DstReg | SrcMemFAddr | ModRM | Src2SS, em_lseg),
@@ -4473,10 +4597,10 @@ done_prefixes:
         /* Decode and fetch the destination operand: register or memory. */
         rc = decode_operand(ctxt, &ctxt->dst, (ctxt->d >> DstShift) & OpMask);
 
-done:
         if (ctxt->rip_relative)
                 ctxt->memopp->addr.mem.ea += ctxt->_eip;
 
+done:
         return (rc != X86EMUL_CONTINUE) ? EMULATION_FAILED : EMULATION_OK;
 }
 
@@ -4726,7 +4850,7 @@ special_insn:
                 break;
         case 0x70 ... 0x7f: /* jcc (short) */
                 if (test_cc(ctxt->b, ctxt->eflags))
-                        jmp_rel(ctxt, ctxt->src.val);
+                        rc = jmp_rel(ctxt, ctxt->src.val);
                 break;
         case 0x8d: /* lea r16/r32, m */
                 ctxt->dst.val = ctxt->src.addr.mem.ea;
@@ -4756,7 +4880,7 @@ special_insn:
                 break;
         case 0xe9: /* jmp rel */
         case 0xeb: /* jmp rel short */
-                jmp_rel(ctxt, ctxt->src.val);
+                rc = jmp_rel(ctxt, ctxt->src.val);
                 ctxt->dst.type = OP_NONE; /* Disable writeback. */
                 break;
         case 0xf4:              /* hlt */
@@ -4881,13 +5005,11 @@ twobyte_insn:
                 break;
         case 0x80 ... 0x8f: /* jnz rel, etc*/
                 if (test_cc(ctxt->b, ctxt->eflags))
-                        jmp_rel(ctxt, ctxt->src.val);
+                        rc = jmp_rel(ctxt, ctxt->src.val);
                 break;
         case 0x90 ... 0x9f:     /* setcc r/m8 */
                 ctxt->dst.val = test_cc(ctxt->b, ctxt->eflags);
                 break;
-        case 0xae:              /* clflush */
-                break;
         case 0xb6 ... 0xb7:     /* movzx */
                 ctxt->dst.bytes = ctxt->op_bytes;
                 ctxt->dst.val = (ctxt->src.bytes == 1) ? (u8) ctxt->src.val