1 files changed, 440 insertions, 149 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 1be5cd640e93..4dade6ac0827 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -32,7 +32,7 @@
 #include <linux/module.h>
 #include <asm/kvm_emulate.h>
 
-#include "mmu.h"                /* for is_long_mode() */
+#include "x86.h"
 
 /*
  * Opcode effective-address decode tables.
@@ -75,6 +75,10 @@
 #define Group       (1<<14)     /* Bits 3:5 of modrm byte extend opcode */
 #define GroupDual   (1<<15)     /* Alternate decoding of mod == 3 */
 #define GroupMask   0xff        /* Group number stored in bits 0:7 */
+/* Misc flags */
+#define Lock        (1<<26) /* lock prefix is allowed for the instruction */
+#define Priv        (1<<27) /* instruction generates #GP if current CPL != 0 */
+#define No64        (1<<28)
 /* Source 2 operand type */
 #define Src2None    (0<<29)
 #define Src2CL      (1<<29)
@@ -86,35 +90,40 @@
 enum {
         Group1_80, Group1_81, Group1_82, Group1_83,
         Group1A, Group3_Byte, Group3, Group4, Group5, Group7,
+        Group8, Group9,
 };
 
 static u32 opcode_table[256] = {
         /* 0x00 - 0x07 */
-        ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
+        ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,
         ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
-        ByteOp | DstAcc | SrcImm, DstAcc | SrcImm, 0, 0,
+        ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,
+        ImplicitOps | Stack | No64, ImplicitOps | Stack | No64,
         /* 0x08 - 0x0F */
-        ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
+        ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,
         ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
-        0, 0, 0, 0,
+        ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,
+        ImplicitOps | Stack | No64, 0,
         /* 0x10 - 0x17 */
-        ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
+        ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,
         ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
-        ByteOp | DstAcc | SrcImm, DstAcc | SrcImm, 0, 0,
+        ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,
+        ImplicitOps | Stack | No64, ImplicitOps | Stack | No64,
         /* 0x18 - 0x1F */
-        ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
+        ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,
         ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
-        ByteOp | DstAcc | SrcImm, DstAcc | SrcImm, 0, 0,
+        ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,
+        ImplicitOps | Stack | No64, ImplicitOps | Stack | No64,
         /* 0x20 - 0x27 */
-        ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
+        ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,
         ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
         DstAcc | SrcImmByte, DstAcc | SrcImm, 0, 0,
         /* 0x28 - 0x2F */
-        ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
+        ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,
         ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
         0, 0, 0, 0,
         /* 0x30 - 0x37 */
-        ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
+        ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,
         ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
         0, 0, 0, 0,
         /* 0x38 - 0x3F */
@@ -133,7 +142,8 @@ static u32 opcode_table[256] = {
         DstReg | Stack, DstReg | Stack, DstReg | Stack, DstReg | Stack,
         DstReg | Stack, DstReg | Stack, DstReg | Stack, DstReg | Stack,
         /* 0x60 - 0x67 */
-        0, 0, 0, DstReg | SrcMem32 | ModRM | Mov /* movsxd (x86/64) */ ,
+        ImplicitOps | Stack | No64, ImplicitOps | Stack | No64,
+        0, DstReg | SrcMem32 | ModRM | Mov /* movsxd (x86/64) */ ,
         0, 0, 0, 0,
         /* 0x68 - 0x6F */
         SrcImm | Mov | Stack, 0, SrcImmByte | Mov | Stack, 0,
@@ -149,7 +159,7 @@ static u32 opcode_table[256] = {
         Group | Group1_80, Group | Group1_81,
         Group | Group1_82, Group | Group1_83,
         ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
-        ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
+        ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,
         /* 0x88 - 0x8F */
         ByteOp | DstMem | SrcReg | ModRM | Mov, DstMem | SrcReg | ModRM | Mov,
         ByteOp | DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
@@ -158,7 +168,7 @@ static u32 opcode_table[256] = {
         /* 0x90 - 0x97 */
         DstReg, DstReg, DstReg, DstReg, DstReg, DstReg, DstReg, DstReg,
         /* 0x98 - 0x9F */
-        0, 0, SrcImm | Src2Imm16, 0,
+        0, 0, SrcImm | Src2Imm16 | No64, 0,
         ImplicitOps | Stack, ImplicitOps | Stack, 0, 0,
         /* 0xA0 - 0xA7 */
         ByteOp | DstReg | SrcMem | Mov | MemAbs, DstReg | SrcMem | Mov | MemAbs,
@@ -185,7 +195,7 @@ static u32 opcode_table[256] = {
         ByteOp | DstMem | SrcImm | ModRM | Mov, DstMem | SrcImm | ModRM | Mov,
         /* 0xC8 - 0xCF */
         0, 0, 0, ImplicitOps | Stack,
-        ImplicitOps, SrcImmByte, ImplicitOps, ImplicitOps,
+        ImplicitOps, SrcImmByte, ImplicitOps | No64, ImplicitOps,
         /* 0xD0 - 0xD7 */
         ByteOp | DstMem | SrcImplicit | ModRM, DstMem | SrcImplicit | ModRM,
         ByteOp | DstMem | SrcImplicit | ModRM, DstMem | SrcImplicit | ModRM,
@@ -198,12 +208,12 @@ static u32 opcode_table[256] = {
         ByteOp | SrcImmUByte, SrcImmUByte,
         /* 0xE8 - 0xEF */
         SrcImm | Stack, SrcImm | ImplicitOps,
-        SrcImmU | Src2Imm16, SrcImmByte | ImplicitOps,
+        SrcImmU | Src2Imm16 | No64, SrcImmByte | ImplicitOps,
         SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps,
         SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps,
         /* 0xF0 - 0xF7 */
         0, 0, 0, 0,
-        ImplicitOps, ImplicitOps, Group | Group3_Byte, Group | Group3,
+        ImplicitOps | Priv, ImplicitOps, Group | Group3_Byte, Group | Group3,
         /* 0xF8 - 0xFF */
         ImplicitOps, 0, ImplicitOps, ImplicitOps,
         ImplicitOps, ImplicitOps, Group | Group4, Group | Group5,
@@ -211,16 +221,20 @@ static u32 opcode_table[256] = {
 
 static u32 twobyte_table[256] = {
         /* 0x00 - 0x0F */
-        0, Group | GroupDual | Group7, 0, 0, 0, ImplicitOps, ImplicitOps, 0,
-        ImplicitOps, ImplicitOps, 0, 0, 0, ImplicitOps | ModRM, 0, 0,
+        0, Group | GroupDual | Group7, 0, 0,
+        0, ImplicitOps, ImplicitOps | Priv, 0,
+        ImplicitOps | Priv, ImplicitOps | Priv, 0, 0,
+        0, ImplicitOps | ModRM, 0, 0,
         /* 0x10 - 0x1F */
         0, 0, 0, 0, 0, 0, 0, 0, ImplicitOps | ModRM, 0, 0, 0, 0, 0, 0, 0,
         /* 0x20 - 0x2F */
-        ModRM | ImplicitOps, ModRM, ModRM | ImplicitOps, ModRM, 0, 0, 0, 0,
+        ModRM | ImplicitOps | Priv, ModRM | Priv,
+        ModRM | ImplicitOps | Priv, ModRM | Priv,
+        0, 0, 0, 0,
         0, 0, 0, 0, 0, 0, 0, 0,
         /* 0x30 - 0x3F */
-        ImplicitOps, 0, ImplicitOps, 0,
-        ImplicitOps, ImplicitOps, 0, 0,
+        ImplicitOps | Priv, 0, ImplicitOps | Priv, 0,
+        ImplicitOps, ImplicitOps | Priv, 0, 0,
         0, 0, 0, 0, 0, 0, 0, 0,
         /* 0x40 - 0x47 */
         DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
@@ -244,25 +258,29 @@ static u32 twobyte_table[256] = {
         /* 0x90 - 0x9F */
         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
         /* 0xA0 - 0xA7 */
-        0, 0, 0, DstMem | SrcReg | ModRM | BitOp,
+        ImplicitOps | Stack, ImplicitOps | Stack,
+        0, DstMem | SrcReg | ModRM | BitOp,
         DstMem | SrcReg | Src2ImmByte | ModRM,
         DstMem | SrcReg | Src2CL | ModRM, 0, 0,
         /* 0xA8 - 0xAF */
-        0, 0, 0, DstMem | SrcReg | ModRM | BitOp,
+        ImplicitOps | Stack, ImplicitOps | Stack,
+        0, DstMem | SrcReg | ModRM | BitOp | Lock,
         DstMem | SrcReg | Src2ImmByte | ModRM,
         DstMem | SrcReg | Src2CL | ModRM,
         ModRM, 0,
         /* 0xB0 - 0xB7 */
-        ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, 0,
-            DstMem | SrcReg | ModRM | BitOp,
+        ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,
+        0, DstMem | SrcReg | ModRM | BitOp | Lock,
         0, 0, ByteOp | DstReg | SrcMem | ModRM | Mov,
             DstReg | SrcMem16 | ModRM | Mov,
         /* 0xB8 - 0xBF */
-        0, 0, DstMem | SrcImmByte | ModRM, DstMem | SrcReg | ModRM | BitOp,
+        0, 0,
+        Group | Group8, DstMem | SrcReg | ModRM | BitOp | Lock,
         0, 0, ByteOp | DstReg | SrcMem | ModRM | Mov,
             DstReg | SrcMem16 | ModRM | Mov,
         /* 0xC0 - 0xCF */
-        0, 0, 0, DstMem | SrcReg | ModRM | Mov, 0, 0, 0, ImplicitOps | ModRM,
+        0, 0, 0, DstMem | SrcReg | ModRM | Mov,
+        0, 0, 0, Group | GroupDual | Group9,
         0, 0, 0, 0, 0, 0, 0, 0,
         /* 0xD0 - 0xDF */
         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
@@ -274,25 +292,41 @@ static u32 twobyte_table[256] = {
 
 static u32 group_table[] = {
         [Group1_80*8] =
-        ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
-        ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
-        ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
-        ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
+        ByteOp | DstMem | SrcImm | ModRM | Lock,
+        ByteOp | DstMem | SrcImm | ModRM | Lock,
+        ByteOp | DstMem | SrcImm | ModRM | Lock,
+        ByteOp | DstMem | SrcImm | ModRM | Lock,
+        ByteOp | DstMem | SrcImm | ModRM | Lock,
+        ByteOp | DstMem | SrcImm | ModRM | Lock,
+        ByteOp | DstMem | SrcImm | ModRM | Lock,
+        ByteOp | DstMem | SrcImm | ModRM,
         [Group1_81*8] =
-        DstMem | SrcImm | ModRM, DstMem | SrcImm | ModRM,
-        DstMem | SrcImm | ModRM, DstMem | SrcImm | ModRM,
-        DstMem | SrcImm | ModRM, DstMem | SrcImm | ModRM,
-        DstMem | SrcImm | ModRM, DstMem | SrcImm | ModRM,
+        DstMem | SrcImm | ModRM | Lock,
+        DstMem | SrcImm | ModRM | Lock,
+        DstMem | SrcImm | ModRM | Lock,
+        DstMem | SrcImm | ModRM | Lock,
+        DstMem | SrcImm | ModRM | Lock,
+        DstMem | SrcImm | ModRM | Lock,
+        DstMem | SrcImm | ModRM | Lock,
+        DstMem | SrcImm | ModRM,
         [Group1_82*8] =
-        ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
-        ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
-        ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
-        ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
+        ByteOp | DstMem | SrcImm | ModRM | No64 | Lock,
+        ByteOp | DstMem | SrcImm | ModRM | No64 | Lock,
+        ByteOp | DstMem | SrcImm | ModRM | No64 | Lock,
+        ByteOp | DstMem | SrcImm | ModRM | No64 | Lock,
+        ByteOp | DstMem | SrcImm | ModRM | No64 | Lock,
+        ByteOp | DstMem | SrcImm | ModRM | No64 | Lock,
+        ByteOp | DstMem | SrcImm | ModRM | No64 | Lock,
+        ByteOp | DstMem | SrcImm | ModRM | No64,
         [Group1_83*8] =
-        DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM,
-        DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM,
-        DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM,
-        DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM,
+        DstMem | SrcImmByte | ModRM | Lock,
+        DstMem | SrcImmByte | ModRM | Lock,
+        DstMem | SrcImmByte | ModRM | Lock,
+        DstMem | SrcImmByte | ModRM | Lock,
+        DstMem | SrcImmByte | ModRM | Lock,
+        DstMem | SrcImmByte | ModRM | Lock,
+        DstMem | SrcImmByte | ModRM | Lock,
+        DstMem | SrcImmByte | ModRM,
         [Group1A*8] =
         DstMem | SrcNone | ModRM | Mov | Stack, 0, 0, 0, 0, 0, 0, 0,
         [Group3_Byte*8] =
@@ -311,24 +345,39 @@ static u32 group_table[] = {
         SrcMem | ModRM | Stack, 0,
         SrcMem | ModRM | Stack, 0, SrcMem | ModRM | Stack, 0,
         [Group7*8] =
-        0, 0, ModRM | SrcMem, ModRM | SrcMem,
+        0, 0, ModRM | SrcMem | Priv, ModRM | SrcMem | Priv,
         SrcNone | ModRM | DstMem | Mov, 0,
-        SrcMem16 | ModRM | Mov, SrcMem | ModRM | ByteOp,
+        SrcMem16 | ModRM | Mov | Priv, SrcMem | ModRM | ByteOp | Priv,
+        [Group8*8] =
+        0, 0, 0, 0,
+        DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM | Lock,
+        DstMem | SrcImmByte | ModRM | Lock, DstMem | SrcImmByte | ModRM | Lock,
+        [Group9*8] =
+        0, ImplicitOps | ModRM | Lock, 0, 0, 0, 0, 0, 0,
 };
 
 static u32 group2_table[] = {
         [Group7*8] =
-        SrcNone | ModRM, 0, 0, SrcNone | ModRM,
+        SrcNone | ModRM | Priv, 0, 0, SrcNone | ModRM,
         SrcNone | ModRM | DstMem | Mov, 0,
         SrcMem16 | ModRM | Mov, 0,
+        [Group9*8] =
+        0, 0, 0, 0, 0, 0, 0, 0,
 };
 
 /* EFLAGS bit definitions. */
+#define EFLG_ID (1<<21)
+#define EFLG_VIP (1<<20)
+#define EFLG_VIF (1<<19)
+#define EFLG_AC (1<<18)
 #define EFLG_VM (1<<17)
 #define EFLG_RF (1<<16)
+#define EFLG_IOPL (3<<12)
+#define EFLG_NT (1<<14)
 #define EFLG_OF (1<<11)
 #define EFLG_DF (1<<10)
 #define EFLG_IF (1<<9)
+#define EFLG_TF (1<<8)
 #define EFLG_SF (1<<7)
 #define EFLG_ZF (1<<6)
 #define EFLG_AF (1<<4)
@@ -597,7 +646,7 @@ static int do_fetch_insn_byte(struct x86_emulate_ctxt *ctxt,
 
         if (linear < fc->start || linear >= fc->end) {
                 size = min(15UL, PAGE_SIZE - offset_in_page(linear));
-                rc = ops->read_std(linear, fc->data, size, ctxt->vcpu);
+                rc = ops->fetch(linear, fc->data, size, ctxt->vcpu, NULL);
                 if (rc)
                         return rc;
                 fc->start = linear;
@@ -613,6 +662,9 @@ static int do_insn_fetch(struct x86_emulate_ctxt *ctxt,
 {
         int rc = 0;
 
+        /* x86 instructions are limited to 15 bytes. */
+        if (eip + size - ctxt->decode.eip_orig > 15)
+                return X86EMUL_UNHANDLEABLE;
         eip += ctxt->cs_base;
         while (size--) {
                 rc = do_fetch_insn_byte(ctxt, ops, eip++, dest++);
@@ -649,11 +701,11 @@ static int read_descriptor(struct x86_emulate_ctxt *ctxt,
                 op_bytes = 3;
         *address = 0;
         rc = ops->read_std((unsigned long)ptr, (unsigned long *)size, 2,
-                           ctxt->vcpu);
+                           ctxt->vcpu, NULL);
         if (rc)
                 return rc;
         rc = ops->read_std((unsigned long)ptr + 2, address, op_bytes,
-                           ctxt->vcpu);
+                           ctxt->vcpu, NULL);
         return rc;
 }
 
@@ -871,12 +923,13 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
         /* Shadow copy of register state. Committed on successful emulation. */
 
         memset(c, 0, sizeof(struct decode_cache));
-        c->eip = kvm_rip_read(ctxt->vcpu);
+        c->eip = c->eip_orig = kvm_rip_read(ctxt->vcpu);
         ctxt->cs_base = seg_base(ctxt, VCPU_SREG_CS);
         memcpy(c->regs, ctxt->vcpu->arch.regs, sizeof c->regs);
 
         switch (mode) {
         case X86EMUL_MODE_REAL:
+        case X86EMUL_MODE_VM86:
         case X86EMUL_MODE_PROT16:
                 def_op_bytes = def_ad_bytes = 2;
                 break;
@@ -962,6 +1015,11 @@ done_prefixes:
                 }
         }
 
+        if (mode == X86EMUL_MODE_PROT64 && (c->d & No64)) {
+                kvm_report_emulation_failure(ctxt->vcpu, "invalid x86/64 instruction");
+                return -1;
+        }
+
         if (c->d & Group) {
                 group = c->d & GroupMask;
                 c->modrm = insn_fetch(u8, 1, c->eip);
@@ -1179,13 +1237,119 @@ static int emulate_pop(struct x86_emulate_ctxt *ctxt,
         rc = ops->read_emulated(register_address(c, ss_base(ctxt),
                                                  c->regs[VCPU_REGS_RSP]),
                                 dest, len, ctxt->vcpu);
-        if (rc != 0)
+        if (rc != X86EMUL_CONTINUE)
                 return rc;
 
         register_address_increment(c, &c->regs[VCPU_REGS_RSP], len);
         return rc;
 }
 
+static int emulate_popf(struct x86_emulate_ctxt *ctxt,
+                       struct x86_emulate_ops *ops,
+                       void *dest, int len)
+{
+        int rc;
+        unsigned long val, change_mask;
+        int iopl = (ctxt->eflags & X86_EFLAGS_IOPL) >> IOPL_SHIFT;
+        int cpl = kvm_x86_ops->get_cpl(ctxt->vcpu);
+
+        rc = emulate_pop(ctxt, ops, &val, len);
+        if (rc != X86EMUL_CONTINUE)
+                return rc;
+
+        change_mask = EFLG_CF | EFLG_PF | EFLG_AF | EFLG_ZF | EFLG_SF | EFLG_OF
+                | EFLG_TF | EFLG_DF | EFLG_NT | EFLG_RF | EFLG_AC | EFLG_ID;
+
+        switch(ctxt->mode) {
+        case X86EMUL_MODE_PROT64:
+        case X86EMUL_MODE_PROT32:
+        case X86EMUL_MODE_PROT16:
+                if (cpl == 0)
+                        change_mask |= EFLG_IOPL;
+                if (cpl <= iopl)
+                        change_mask |= EFLG_IF;
+                break;
+        case X86EMUL_MODE_VM86:
+                if (iopl < 3) {
+                        kvm_inject_gp(ctxt->vcpu, 0);
+                        return X86EMUL_PROPAGATE_FAULT;
+                }
+                change_mask |= EFLG_IF;
+                break;
+        default: /* real mode */
+                change_mask |= (EFLG_IOPL | EFLG_IF);
+                break;
+        }
+
+        *(unsigned long *)dest =
+                (ctxt->eflags & ~change_mask) | (val & change_mask);
+
+        return rc;
+}
+
+static void emulate_push_sreg(struct x86_emulate_ctxt *ctxt, int seg)
+{
+        struct decode_cache *c = &ctxt->decode;
+        struct kvm_segment segment;
+
+        kvm_x86_ops->get_segment(ctxt->vcpu, &segment, seg);
+
+        c->src.val = segment.selector;
+        emulate_push(ctxt);
+}
+
+static int emulate_pop_sreg(struct x86_emulate_ctxt *ctxt,
+                             struct x86_emulate_ops *ops, int seg)
+{
+        struct decode_cache *c = &ctxt->decode;
+        unsigned long selector;
+        int rc;
+
+        rc = emulate_pop(ctxt, ops, &selector, c->op_bytes);
+        if (rc != 0)
+                return rc;
+
+        rc = kvm_load_segment_descriptor(ctxt->vcpu, (u16)selector, seg);
+        return rc;
+}
+
+static void emulate_pusha(struct x86_emulate_ctxt *ctxt)
+{
+        struct decode_cache *c = &ctxt->decode;
+        unsigned long old_esp = c->regs[VCPU_REGS_RSP];
+        int reg = VCPU_REGS_RAX;
+
+        while (reg <= VCPU_REGS_RDI) {
+                (reg == VCPU_REGS_RSP) ?
+                (c->src.val = old_esp) : (c->src.val = c->regs[reg]);
+
+                emulate_push(ctxt);
+                ++reg;
+        }
+}
+
+static int emulate_popa(struct x86_emulate_ctxt *ctxt,
+                        struct x86_emulate_ops *ops)
+{
+        struct decode_cache *c = &ctxt->decode;
+        int rc = 0;
+        int reg = VCPU_REGS_RDI;
+
+        while (reg >= VCPU_REGS_RAX) {
+                if (reg == VCPU_REGS_RSP) {
+                        register_address_increment(c, &c->regs[VCPU_REGS_RSP],
+                                                        c->op_bytes);
+                        --reg;
+                }
+
+                rc = emulate_pop(ctxt, ops, &c->regs[reg], c->op_bytes);
+                if (rc != 0)
+                        break;
+                --reg;
+        }
+        return rc;
+}
+
 static inline int emulate_grp1a(struct x86_emulate_ctxt *ctxt,
                                 struct x86_emulate_ops *ops)
 {
@@ -1290,7 +1454,7 @@ static inline int emulate_grp9(struct x86_emulate_ctxt *ctxt,
         int rc;
 
         rc = ops->read_emulated(memop, &old, 8, ctxt->vcpu);
-        if (rc != 0)
+        if (rc != X86EMUL_CONTINUE)
                 return rc;
 
         if (((u32) (old >> 0) != (u32) c->regs[VCPU_REGS_RAX]) ||
@@ -1305,7 +1469,7 @@ static inline int emulate_grp9(struct x86_emulate_ctxt *ctxt,
                        (u32) c->regs[VCPU_REGS_RBX];
 
                 rc = ops->cmpxchg_emulated(memop, &old, &new, 8, ctxt->vcpu);
-                if (rc != 0)
+                if (rc != X86EMUL_CONTINUE)
                         return rc;
                 ctxt->eflags |= EFLG_ZF;
         }
@@ -1327,7 +1491,7 @@ static int emulate_ret_far(struct x86_emulate_ctxt *ctxt,
         rc = emulate_pop(ctxt, ops, &cs, c->op_bytes);
         if (rc)
                 return rc;
-        rc = kvm_load_segment_descriptor(ctxt->vcpu, (u16)cs, 1, VCPU_SREG_CS);
+        rc = kvm_load_segment_descriptor(ctxt->vcpu, (u16)cs, VCPU_SREG_CS);
         return rc;
 }
 
@@ -1371,7 +1535,7 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt,
                                         &c->dst.val,
                                         c->dst.bytes,
                                         ctxt->vcpu);
-                if (rc != 0)
+                if (rc != X86EMUL_CONTINUE)
                         return rc;
                 break;
         case OP_NONE:
@@ -1434,9 +1598,8 @@ emulate_syscall(struct x86_emulate_ctxt *ctxt)
         u64 msr_data;
 
         /* syscall is not available in real mode */
-        if (c->lock_prefix || ctxt->mode == X86EMUL_MODE_REAL
-                || !(ctxt->vcpu->arch.cr0 & X86_CR0_PE))
-                return -1;
+        if (ctxt->mode == X86EMUL_MODE_REAL || ctxt->mode == X86EMUL_MODE_VM86)
+                return X86EMUL_UNHANDLEABLE;
 
         setup_syscalls_segments(ctxt, &cs, &ss);
 
@@ -1473,7 +1636,7 @@ emulate_syscall(struct x86_emulate_ctxt *ctxt)
                 ctxt->eflags &= ~(EFLG_VM | EFLG_IF | EFLG_RF);
         }
 
-        return 0;
+        return X86EMUL_CONTINUE;
 }
 
 static int
@@ -1483,22 +1646,17 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt)
         struct kvm_segment cs, ss;
         u64 msr_data;
 
-        /* inject #UD if LOCK prefix is used */
-        if (c->lock_prefix)
-                return -1;
-
-        /* inject #GP if in real mode or paging is disabled */
-        if (ctxt->mode == X86EMUL_MODE_REAL ||
-                !(ctxt->vcpu->arch.cr0 & X86_CR0_PE)) {
+        /* inject #GP if in real mode */
+        if (ctxt->mode == X86EMUL_MODE_REAL) {
                 kvm_inject_gp(ctxt->vcpu, 0);
-                return -1;
+                return X86EMUL_UNHANDLEABLE;
         }
 
         /* XXX sysenter/sysexit have not been tested in 64bit mode.
         * Therefore, we inject an #UD.
         */
         if (ctxt->mode == X86EMUL_MODE_PROT64)
-                return -1;
+                return X86EMUL_UNHANDLEABLE;
 
         setup_syscalls_segments(ctxt, &cs, &ss);
 
@@ -1507,13 +1665,13 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt)
         case X86EMUL_MODE_PROT32:
                 if ((msr_data & 0xfffc) == 0x0) {
                         kvm_inject_gp(ctxt->vcpu, 0);
-                        return -1;
+                        return X86EMUL_PROPAGATE_FAULT;
                 }
                 break;
         case X86EMUL_MODE_PROT64:
                 if (msr_data == 0x0) {
                         kvm_inject_gp(ctxt->vcpu, 0);
-                        return -1;
+                        return X86EMUL_PROPAGATE_FAULT;
                 }
                 break;
         }
@@ -1538,7 +1696,7 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt)
         kvm_x86_ops->get_msr(ctxt->vcpu, MSR_IA32_SYSENTER_ESP, &msr_data);
         c->regs[VCPU_REGS_RSP] = msr_data;
 
-        return 0;
+        return X86EMUL_CONTINUE;
 }
 
 static int
@@ -1549,21 +1707,11 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt)
         u64 msr_data;
         int usermode;
 
-        /* inject #UD if LOCK prefix is used */
-        if (c->lock_prefix)
-                return -1;
-
-        /* inject #GP if in real mode or paging is disabled */
-        if (ctxt->mode == X86EMUL_MODE_REAL
-                || !(ctxt->vcpu->arch.cr0 & X86_CR0_PE)) {
-                kvm_inject_gp(ctxt->vcpu, 0);
-                return -1;
-        }
-
-        /* sysexit must be called from CPL 0 */
-        if (kvm_x86_ops->get_cpl(ctxt->vcpu) != 0) {
+        /* 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);
-                return -1;
+                return X86EMUL_UNHANDLEABLE;
         }
 
         setup_syscalls_segments(ctxt, &cs, &ss);
@@ -1581,7 +1729,7 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt)
                 cs.selector = (u16)(msr_data + 16);
                 if ((msr_data & 0xfffc) == 0x0) {
                         kvm_inject_gp(ctxt->vcpu, 0);
-                        return -1;
+                        return X86EMUL_PROPAGATE_FAULT;
                 }
                 ss.selector = (u16)(msr_data + 24);
                 break;
@@ -1589,7 +1737,7 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt)
                 cs.selector = (u16)(msr_data + 32);
                 if (msr_data == 0x0) {
                         kvm_inject_gp(ctxt->vcpu, 0);
-                        return -1;
+                        return X86EMUL_PROPAGATE_FAULT;
                 }
                 ss.selector = cs.selector + 8;
                 cs.db = 0;
@@ -1605,7 +1753,58 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt)
         c->eip = ctxt->vcpu->arch.regs[VCPU_REGS_RDX];
         c->regs[VCPU_REGS_RSP] = ctxt->vcpu->arch.regs[VCPU_REGS_RCX];
 
-        return 0;
+        return X86EMUL_CONTINUE;
+}
+
+static bool emulator_bad_iopl(struct x86_emulate_ctxt *ctxt)
+{
+        int iopl;
+        if (ctxt->mode == X86EMUL_MODE_REAL)
+                return false;
+        if (ctxt->mode == X86EMUL_MODE_VM86)
+                return true;
+        iopl = (ctxt->eflags & X86_EFLAGS_IOPL) >> IOPL_SHIFT;
+        return kvm_x86_ops->get_cpl(ctxt->vcpu) > iopl;
+}
+
+static bool emulator_io_port_access_allowed(struct x86_emulate_ctxt *ctxt,
+                                            struct x86_emulate_ops *ops,
+                                            u16 port, u16 len)
+{
+        struct kvm_segment tr_seg;
+        int r;
+        u16 io_bitmap_ptr;
+        u8 perm, bit_idx = port & 0x7;
+        unsigned mask = (1 << len) - 1;
+
+        kvm_get_segment(ctxt->vcpu, &tr_seg, VCPU_SREG_TR);
+        if (tr_seg.unusable)
+                return false;
+        if (tr_seg.limit < 103)
+                return false;
+        r = ops->read_std(tr_seg.base + 102, &io_bitmap_ptr, 2, ctxt->vcpu,
+                          NULL);
+        if (r != X86EMUL_CONTINUE)
+                return false;
+        if (io_bitmap_ptr + port/8 > tr_seg.limit)
+                return false;
+        r = ops->read_std(tr_seg.base + io_bitmap_ptr + port/8, &perm, 1,
+                          ctxt->vcpu, NULL);
+        if (r != X86EMUL_CONTINUE)
+                return false;
+        if ((perm >> bit_idx) & mask)
+                return false;
+        return true;
+}
+
+static bool emulator_io_permited(struct x86_emulate_ctxt *ctxt,
+                                 struct x86_emulate_ops *ops,
+                                 u16 port, u16 len)
+{
+        if (emulator_bad_iopl(ctxt))
+                if (!emulator_io_port_access_allowed(ctxt, ops, port, len))
+                        return false;
+        return true;
 }
 
 int
@@ -1629,6 +1828,18 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
         memcpy(c->regs, ctxt->vcpu->arch.regs, sizeof c->regs);
         saved_eip = c->eip;
 
+        /* LOCK prefix is allowed only with some instructions */
+        if (c->lock_prefix && !(c->d & Lock)) {
+                kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                goto done;
+        }
+
+        /* Privileged instruction can be executed only in CPL=0 */
+        if ((c->d & Priv) && kvm_x86_ops->get_cpl(ctxt->vcpu)) {
+                kvm_inject_gp(ctxt->vcpu, 0);
+                goto done;
+        }
+
         if (((c->d & ModRM) && (c->modrm_mod != 3)) || (c->d & MemAbs))
                 memop = c->modrm_ea;
 
@@ -1669,7 +1880,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
                                         &c->src.val,
                                         c->src.bytes,
                                         ctxt->vcpu);
-                if (rc != 0)
+                if (rc != X86EMUL_CONTINUE)
                         goto done;
                 c->src.orig_val = c->src.val;
         }
@@ -1688,12 +1899,15 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
                         c->dst.ptr = (void *)c->dst.ptr +
                                                    (c->src.val & mask) / 8;
                 }
-                if (!(c->d & Mov) &&
-                                   /* optimisation - avoid slow emulated read */
-                    ((rc = ops->read_emulated((unsigned long)c->dst.ptr,
-                                           &c->dst.val,
-                                          c->dst.bytes, ctxt->vcpu)) != 0))
-                        goto done;
+                if (!(c->d & Mov)) {
+                        /* optimisation - avoid slow emulated read */
+                        rc = ops->read_emulated((unsigned long)c->dst.ptr,
+                                                &c->dst.val,
+                                                c->dst.bytes,
+                                                ctxt->vcpu);
+                        if (rc != X86EMUL_CONTINUE)
+                                goto done;
+                }
         }
         c->dst.orig_val = c->dst.val;
 
@@ -1707,18 +1921,45 @@ special_insn:
               add:              /* add */
                 emulate_2op_SrcV("add", c->src, c->dst, ctxt->eflags);
                 break;
+        case 0x06:              /* push es */
+                emulate_push_sreg(ctxt, VCPU_SREG_ES);
+                break;
+        case 0x07:              /* pop es */
+                rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_ES);
+                if (rc != 0)
+                        goto done;
+                break;
         case 0x08 ... 0x0d:
               or:               /* or */
                 emulate_2op_SrcV("or", c->src, c->dst, ctxt->eflags);
                 break;
+        case 0x0e:              /* push cs */
+                emulate_push_sreg(ctxt, 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, VCPU_SREG_SS);
+                break;
+        case 0x17:              /* pop ss */
+                rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_SS);
+                if (rc != 0)
+                        goto done;
+                break;
         case 0x18 ... 0x1d:
               sbb:              /* sbb */
                 emulate_2op_SrcV("sbb", c->src, c->dst, ctxt->eflags);
                 break;
+        case 0x1e:              /* push ds */
+                emulate_push_sreg(ctxt, VCPU_SREG_DS);
+                break;
+        case 0x1f:              /* pop ds */
+                rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_DS);
+                if (rc != 0)
+                        goto done;
+                break;
         case 0x20 ... 0x25:
               and:              /* and */
                 emulate_2op_SrcV("and", c->src, c->dst, ctxt->eflags);
@@ -1750,6 +1991,14 @@ special_insn:
                 if (rc != 0)
                         goto done;
                 break;
+        case 0x60:      /* pusha */
+                emulate_pusha(ctxt);
+                break;
+        case 0x61:      /* popa */
+                rc = emulate_popa(ctxt, ops);
+                if (rc != 0)
+                        goto done;
+                break;
         case 0x63:              /* movsxd */
                 if (ctxt->mode != X86EMUL_MODE_PROT64)
                         goto cannot_emulate;
@@ -1761,7 +2010,12 @@ special_insn:
                 break;
         case 0x6c:              /* insb */
         case 0x6d:              /* insw/insd */
-                 if (kvm_emulate_pio_string(ctxt->vcpu, NULL,
+                if (!emulator_io_permited(ctxt, ops, c->regs[VCPU_REGS_RDX],
+                                          (c->d & ByteOp) ? 1 : c->op_bytes)) {
+                        kvm_inject_gp(ctxt->vcpu, 0);
+                        goto done;
+                }
+                if (kvm_emulate_pio_string(ctxt->vcpu,
                                 1,
                                 (c->d & ByteOp) ? 1 : c->op_bytes,
                                 c->rep_prefix ?
@@ -1777,7 +2031,12 @@ special_insn:
                 return 0;
         case 0x6e:              /* outsb */
         case 0x6f:              /* outsw/outsd */
-                if (kvm_emulate_pio_string(ctxt->vcpu, NULL,
+                if (!emulator_io_permited(ctxt, ops, c->regs[VCPU_REGS_RDX],
+                                          (c->d & ByteOp) ? 1 : c->op_bytes)) {
+                        kvm_inject_gp(ctxt->vcpu, 0);
+                        goto done;
+                }
+                if (kvm_emulate_pio_string(ctxt->vcpu,
                                 0,
                                 (c->d & ByteOp) ? 1 : c->op_bytes,
                                 c->rep_prefix ?
@@ -1863,25 +2122,19 @@ special_insn:
                 break;
         case 0x8e: { /* mov seg, r/m16 */
                 uint16_t sel;
-                int type_bits;
-                int err;
 
                 sel = c->src.val;
-                if (c->modrm_reg == VCPU_SREG_SS)
-                        toggle_interruptibility(ctxt, X86_SHADOW_INT_MOV_SS);
 
-                if (c->modrm_reg <= 5) {
-                        type_bits = (c->modrm_reg == 1) ? 9 : 1;
-                        err = kvm_load_segment_descriptor(ctxt->vcpu, sel,
-                                                          type_bits, c->modrm_reg);
-                } else {
-                        printk(KERN_INFO "Invalid segreg in modrm byte 0x%02x\n",
-                                        c->modrm);
-                        goto cannot_emulate;
+                if (c->modrm_reg == VCPU_SREG_CS ||
+                    c->modrm_reg > VCPU_SREG_GS) {
+                        kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                        goto done;
                 }
 
-                if (err < 0)
-                        goto cannot_emulate;
+                if (c->modrm_reg == VCPU_SREG_SS)
+                        toggle_interruptibility(ctxt, X86_SHADOW_INT_MOV_SS);
+
+                rc = kvm_load_segment_descriptor(ctxt->vcpu, sel, c->modrm_reg);
 
                 c->dst.type = OP_NONE;  /* Disable writeback. */
                 break;
@@ -1910,7 +2163,10 @@ special_insn:
                 c->dst.type = OP_REG;
                 c->dst.ptr = (unsigned long *) &ctxt->eflags;
                 c->dst.bytes = c->op_bytes;
-                goto pop_instruction;
+                rc = emulate_popf(ctxt, ops, &c->dst.val, c->op_bytes);
+                if (rc != X86EMUL_CONTINUE)
+                        goto done;
+                break;
         case 0xa0 ... 0xa1:     /* mov */
                 c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX];
                 c->dst.val = c->src.val;
@@ -1924,11 +2180,12 @@ special_insn:
                 c->dst.ptr = (unsigned long *)register_address(c,
                                                    es_base(ctxt),
                                                    c->regs[VCPU_REGS_RDI]);
-                if ((rc = ops->read_emulated(register_address(c,
-                                           seg_override_base(ctxt, c),
-                                        c->regs[VCPU_REGS_RSI]),
+                rc = ops->read_emulated(register_address(c,
+                                                seg_override_base(ctxt, c),
+                                                c->regs[VCPU_REGS_RSI]),
                                         &c->dst.val,
-                                        c->dst.bytes, ctxt->vcpu)) != 0)
+                                        c->dst.bytes, ctxt->vcpu);
+                if (rc != X86EMUL_CONTINUE)
                         goto done;
                 register_address_increment(c, &c->regs[VCPU_REGS_RSI],
                                        (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
@@ -1943,10 +2200,11 @@ special_insn:
                 c->src.ptr = (unsigned long *)register_address(c,
                                        seg_override_base(ctxt, c),
                                                    c->regs[VCPU_REGS_RSI]);
-                if ((rc = ops->read_emulated((unsigned long)c->src.ptr,
-                                                &c->src.val,
-                                                c->src.bytes,
-                                                ctxt->vcpu)) != 0)
+                rc = ops->read_emulated((unsigned long)c->src.ptr,
+                                        &c->src.val,
+                                        c->src.bytes,
+                                        ctxt->vcpu);
+                if (rc != X86EMUL_CONTINUE)
                         goto done;
 
                 c->dst.type = OP_NONE; /* Disable writeback. */
@@ -1954,10 +2212,11 @@ special_insn:
                 c->dst.ptr = (unsigned long *)register_address(c,
                                                    es_base(ctxt),
                                                    c->regs[VCPU_REGS_RDI]);
-                if ((rc = ops->read_emulated((unsigned long)c->dst.ptr,
-                                                &c->dst.val,
-                                                c->dst.bytes,
-                                                ctxt->vcpu)) != 0)
+                rc = ops->read_emulated((unsigned long)c->dst.ptr,
+                                        &c->dst.val,
+                                        c->dst.bytes,
+                                        ctxt->vcpu);
+                if (rc != X86EMUL_CONTINUE)
                         goto done;
 
                 DPRINTF("cmps: mem1=0x%p mem2=0x%p\n", c->src.ptr, c->dst.ptr);
@@ -1987,12 +2246,13 @@ special_insn:
                 c->dst.type = OP_REG;
                 c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
                 c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX];
-                if ((rc = ops->read_emulated(register_address(c,
-                                                 seg_override_base(ctxt, c),
-                                                 c->regs[VCPU_REGS_RSI]),
-                                                 &c->dst.val,
-                                                 c->dst.bytes,
-                                                 ctxt->vcpu)) != 0)
+                rc = ops->read_emulated(register_address(c,
+                                                seg_override_base(ctxt, c),
+                                                c->regs[VCPU_REGS_RSI]),
+                                        &c->dst.val,
+                                        c->dst.bytes,
+                                        ctxt->vcpu);
+                if (rc != X86EMUL_CONTINUE)
                         goto done;
                 register_address_increment(c, &c->regs[VCPU_REGS_RSI],
                                        (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
@@ -2048,11 +2308,9 @@ special_insn:
         case 0xe9: /* jmp rel */
                 goto jmp;
         case 0xea: /* jmp far */
-                if (kvm_load_segment_descriptor(ctxt->vcpu, c->src2.val, 9,
-                                        VCPU_SREG_CS) < 0) {
-                        DPRINTF("jmp far: Failed to load CS descriptor\n");
-                        goto cannot_emulate;
-                }
+                if (kvm_load_segment_descriptor(ctxt->vcpu, c->src2.val,
+                                                VCPU_SREG_CS))
+                        goto done;
 
                 c->eip = c->src.val;
                 break;
@@ -2070,7 +2328,13 @@ special_insn:
         case 0xef: /* out (e/r)ax,dx */
                 port = c->regs[VCPU_REGS_RDX];
                 io_dir_in = 0;
-        do_io:  if (kvm_emulate_pio(ctxt->vcpu, NULL, io_dir_in,
+        do_io:
+                if (!emulator_io_permited(ctxt, ops, port,
+                                          (c->d & ByteOp) ? 1 : c->op_bytes)) {
+                        kvm_inject_gp(ctxt->vcpu, 0);
+                        goto done;
+                }
+                if (kvm_emulate_pio(ctxt->vcpu, io_dir_in,
                                    (c->d & ByteOp) ? 1 : c->op_bytes,
                                    port) != 0) {
                         c->eip = saved_eip;
@@ -2095,13 +2359,21 @@ special_insn:
                 c->dst.type = OP_NONE;  /* Disable writeback. */
                 break;
         case 0xfa: /* cli */
-                ctxt->eflags &= ~X86_EFLAGS_IF;
-                c->dst.type = OP_NONE;  /* Disable writeback. */
+                if (emulator_bad_iopl(ctxt))
+                        kvm_inject_gp(ctxt->vcpu, 0);
+                else {
+                        ctxt->eflags &= ~X86_EFLAGS_IF;
+                        c->dst.type = OP_NONE;  /* Disable writeback. */
+                }
                 break;
         case 0xfb: /* sti */
-                toggle_interruptibility(ctxt, X86_SHADOW_INT_STI);
-                ctxt->eflags |= X86_EFLAGS_IF;
-                c->dst.type = OP_NONE;  /* Disable writeback. */
+                if (emulator_bad_iopl(ctxt))
+                        kvm_inject_gp(ctxt->vcpu, 0);
+                else {
+                        toggle_interruptibility(ctxt, X86_SHADOW_INT_STI);
+                        ctxt->eflags |= X86_EFLAGS_IF;
+                        c->dst.type = OP_NONE;  /* Disable writeback. */
+                }
                 break;
         case 0xfc: /* cld */
                 ctxt->eflags &= ~EFLG_DF;
@@ -2204,8 +2476,9 @@ twobyte_insn:
                 }
                 break;
         case 0x05:              /* syscall */
-                if (emulate_syscall(ctxt) == -1)
-                        goto cannot_emulate;
+                rc = emulate_syscall(ctxt);
+                if (rc != X86EMUL_CONTINUE)
+                        goto done;
                 else
                         goto writeback;
                 break;
@@ -2276,14 +2549,16 @@ twobyte_insn:
                 c->dst.type = OP_NONE;
                 break;
         case 0x34:              /* sysenter */
-                if (emulate_sysenter(ctxt) == -1)
-                        goto cannot_emulate;
+                rc = emulate_sysenter(ctxt);
+                if (rc != X86EMUL_CONTINUE)
+                        goto done;
                 else
                         goto writeback;
                 break;
         case 0x35:              /* sysexit */
-                if (emulate_sysexit(ctxt) == -1)
-                        goto cannot_emulate;
+                rc = emulate_sysexit(ctxt);
+                if (rc != X86EMUL_CONTINUE)
+                        goto done;
                 else
                         goto writeback;
                 break;
@@ -2297,6 +2572,14 @@ twobyte_insn:
                         jmp_rel(c, c->src.val);
                 c->dst.type = OP_NONE;
                 break;
+        case 0xa0:        /* push fs */
+                emulate_push_sreg(ctxt, VCPU_SREG_FS);
+                break;
+        case 0xa1:       /* pop fs */
+                rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_FS);
+                if (rc != 0)
+                        goto done;
+                break;
         case 0xa3:
               bt:               /* bt */
                 c->dst.type = OP_NONE;
@@ -2308,6 +2591,14 @@ twobyte_insn:
         case 0xa5: /* shld cl, r, r/m */
                 emulate_2op_cl("shld", c->src2, c->src, c->dst, ctxt->eflags);
                 break;
+        case 0xa8:      /* push gs */
+                emulate_push_sreg(ctxt, VCPU_SREG_GS);
+                break;
+        case 0xa9:      /* pop gs */
+                rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_GS);
+                if (rc != 0)
+                        goto done;
+                break;
         case 0xab:
               bts:              /* bts */
                 /* only subword offset */