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Diffstat (limited to 'arch/x86/kvm/x86_emulate.c')
-rw-r--r--arch/x86/kvm/x86_emulate.c141
1 files changed, 63 insertions, 78 deletions
diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c
index ca91749d2083..c1b6c232e02b 100644
--- a/arch/x86/kvm/x86_emulate.c
+++ b/arch/x86/kvm/x86_emulate.c
@@ -59,13 +59,14 @@
#define SrcImm (5<<4) /* Immediate operand. */
#define SrcImmByte (6<<4) /* 8-bit sign-extended immediate operand. */
#define SrcOne (7<<4) /* Implied '1' */
-#define SrcMask (7<<4)
+#define SrcImmUByte (8<<4) /* 8-bit unsigned immediate operand. */
+#define SrcMask (0xf<<4)
/* Generic ModRM decode. */
-#define ModRM (1<<7)
+#define ModRM (1<<8)
/* Destination is only written; never read. */
-#define Mov (1<<8)
-#define BitOp (1<<9)
-#define MemAbs (1<<10) /* Memory operand is absolute displacement */
+#define Mov (1<<9)
+#define BitOp (1<<10)
+#define MemAbs (1<<11) /* Memory operand is absolute displacement */
#define String (1<<12) /* String instruction (rep capable) */
#define Stack (1<<13) /* Stack instruction (push/pop) */
#define Group (1<<14) /* Bits 3:5 of modrm byte extend opcode */
@@ -76,6 +77,7 @@
#define Src2CL (1<<29)
#define Src2ImmByte (2<<29)
#define Src2One (3<<29)
+#define Src2Imm16 (4<<29)
#define Src2Mask (7<<29)
enum {
@@ -135,11 +137,11 @@ static u32 opcode_table[256] = {
SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps, /* insb, insw/insd */
SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps, /* outsb, outsw/outsd */
/* 0x70 - 0x77 */
- ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
- ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
+ SrcImmByte, SrcImmByte, SrcImmByte, SrcImmByte,
+ SrcImmByte, SrcImmByte, SrcImmByte, SrcImmByte,
/* 0x78 - 0x7F */
- ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
- ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
+ SrcImmByte, SrcImmByte, SrcImmByte, SrcImmByte,
+ SrcImmByte, SrcImmByte, SrcImmByte, SrcImmByte,
/* 0x80 - 0x87 */
Group | Group1_80, Group | Group1_81,
Group | Group1_82, Group | Group1_83,
@@ -153,7 +155,8 @@ static u32 opcode_table[256] = {
/* 0x90 - 0x97 */
DstReg, DstReg, DstReg, DstReg, DstReg, DstReg, DstReg, DstReg,
/* 0x98 - 0x9F */
- 0, 0, 0, 0, ImplicitOps | Stack, ImplicitOps | Stack, 0, 0,
+ 0, 0, SrcImm | Src2Imm16, 0,
+ ImplicitOps | Stack, ImplicitOps | Stack, 0, 0,
/* 0xA0 - 0xA7 */
ByteOp | DstReg | SrcMem | Mov | MemAbs, DstReg | SrcMem | Mov | MemAbs,
ByteOp | DstMem | SrcReg | Mov | MemAbs, DstMem | SrcReg | Mov | MemAbs,
@@ -178,7 +181,8 @@ static u32 opcode_table[256] = {
0, ImplicitOps | Stack, 0, 0,
ByteOp | DstMem | SrcImm | ModRM | Mov, DstMem | SrcImm | ModRM | Mov,
/* 0xC8 - 0xCF */
- 0, 0, 0, ImplicitOps | Stack, 0, 0, 0, 0,
+ 0, 0, 0, ImplicitOps | Stack,
+ ImplicitOps, SrcImmByte, ImplicitOps, ImplicitOps,
/* 0xD0 - 0xD7 */
ByteOp | DstMem | SrcImplicit | ModRM, DstMem | SrcImplicit | ModRM,
ByteOp | DstMem | SrcImplicit | ModRM, DstMem | SrcImplicit | ModRM,
@@ -187,11 +191,11 @@ static u32 opcode_table[256] = {
0, 0, 0, 0, 0, 0, 0, 0,
/* 0xE0 - 0xE7 */
0, 0, 0, 0,
- SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps,
- SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps,
+ ByteOp | SrcImmUByte, SrcImmUByte,
+ ByteOp | SrcImmUByte, SrcImmUByte,
/* 0xE8 - 0xEF */
- ImplicitOps | Stack, SrcImm | ImplicitOps,
- ImplicitOps, SrcImmByte | ImplicitOps,
+ SrcImm | Stack, SrcImm | ImplicitOps,
+ SrcImm | Src2Imm16, SrcImmByte | ImplicitOps,
SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps,
SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps,
/* 0xF0 - 0xF7 */
@@ -230,10 +234,8 @@ static u32 twobyte_table[256] = {
/* 0x70 - 0x7F */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 0x80 - 0x8F */
- ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
- ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
- ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
- ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
+ SrcImm, SrcImm, SrcImm, SrcImm, SrcImm, SrcImm, SrcImm, SrcImm,
+ SrcImm, SrcImm, SrcImm, SrcImm, SrcImm, SrcImm, SrcImm, SrcImm,
/* 0x90 - 0x9F */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 0xA0 - 0xA7 */
@@ -1044,10 +1046,14 @@ done_prefixes:
}
break;
case SrcImmByte:
+ case SrcImmUByte:
c->src.type = OP_IMM;
c->src.ptr = (unsigned long *)c->eip;
c->src.bytes = 1;
- c->src.val = insn_fetch(s8, 1, c->eip);
+ if ((c->d & SrcMask) == SrcImmByte)
+ c->src.val = insn_fetch(s8, 1, c->eip);
+ else
+ c->src.val = insn_fetch(u8, 1, c->eip);
break;
case SrcOne:
c->src.bytes = 1;
@@ -1072,6 +1078,12 @@ done_prefixes:
c->src2.bytes = 1;
c->src2.val = insn_fetch(u8, 1, c->eip);
break;
+ case Src2Imm16:
+ c->src2.type = OP_IMM;
+ c->src2.ptr = (unsigned long *)c->eip;
+ c->src2.bytes = 2;
+ c->src2.val = insn_fetch(u16, 2, c->eip);
+ break;
case Src2One:
c->src2.bytes = 1;
c->src2.val = 1;
@@ -1349,6 +1361,20 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt,
return 0;
}
+void toggle_interruptibility(struct x86_emulate_ctxt *ctxt, u32 mask)
+{
+ u32 int_shadow = kvm_x86_ops->get_interrupt_shadow(ctxt->vcpu, mask);
+ /*
+ * an sti; sti; sequence only disable interrupts for the first
+ * instruction. So, if the last instruction, be it emulated or
+ * not, left the system with the INT_STI flag enabled, it
+ * means that the last instruction is an sti. We should not
+ * leave the flag on in this case. The same goes for mov ss
+ */
+ if (!(int_shadow & mask))
+ ctxt->interruptibility = mask;
+}
+
int
x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
{
@@ -1360,6 +1386,8 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
int io_dir_in;
int rc = 0;
+ ctxt->interruptibility = 0;
+
/* Shadow copy of register state. Committed on successful emulation.
* NOTE: we can copy them from vcpu as x86_decode_insn() doesn't
* modify them.
@@ -1531,13 +1559,10 @@ special_insn:
return -1;
}
return 0;
- case 0x70 ... 0x7f: /* jcc (short) */ {
- int rel = insn_fetch(s8, 1, c->eip);
-
+ case 0x70 ... 0x7f: /* jcc (short) */
if (test_cc(c->b, ctxt->eflags))
- jmp_rel(c, rel);
+ jmp_rel(c, c->src.val);
break;
- }
case 0x80 ... 0x83: /* Grp1 */
switch (c->modrm_reg) {
case 0:
@@ -1609,6 +1634,9 @@ special_insn:
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,
@@ -1769,59 +1797,32 @@ special_insn:
break;
case 0xe4: /* inb */
case 0xe5: /* in */
- port = insn_fetch(u8, 1, c->eip);
+ port = c->src.val;
io_dir_in = 1;
goto do_io;
case 0xe6: /* outb */
case 0xe7: /* out */
- port = insn_fetch(u8, 1, c->eip);
+ port = c->src.val;
io_dir_in = 0;
goto do_io;
case 0xe8: /* call (near) */ {
- long int rel;
- switch (c->op_bytes) {
- case 2:
- rel = insn_fetch(s16, 2, c->eip);
- break;
- case 4:
- rel = insn_fetch(s32, 4, c->eip);
- break;
- default:
- DPRINTF("Call: Invalid op_bytes\n");
- goto cannot_emulate;
- }
+ long int rel = c->src.val;
c->src.val = (unsigned long) c->eip;
jmp_rel(c, rel);
- c->op_bytes = c->ad_bytes;
emulate_push(ctxt);
break;
}
case 0xe9: /* jmp rel */
goto jmp;
- case 0xea: /* jmp far */ {
- uint32_t eip;
- uint16_t sel;
-
- switch (c->op_bytes) {
- case 2:
- eip = insn_fetch(u16, 2, c->eip);
- break;
- case 4:
- eip = insn_fetch(u32, 4, c->eip);
- break;
- default:
- DPRINTF("jmp far: Invalid op_bytes\n");
- goto cannot_emulate;
- }
- sel = insn_fetch(u16, 2, c->eip);
- if (kvm_load_segment_descriptor(ctxt->vcpu, sel, 9, VCPU_SREG_CS) < 0) {
+ 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;
}
- c->eip = eip;
+ c->eip = c->src.val;
break;
- }
case 0xeb:
jmp: /* jmp rel short */
jmp_rel(c, c->src.val);
@@ -1865,6 +1866,7 @@ special_insn:
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. */
break;
@@ -2039,28 +2041,11 @@ twobyte_insn:
if (!test_cc(c->b, ctxt->eflags))
c->dst.type = OP_NONE; /* no writeback */
break;
- case 0x80 ... 0x8f: /* jnz rel, etc*/ {
- long int rel;
-
- switch (c->op_bytes) {
- case 2:
- rel = insn_fetch(s16, 2, c->eip);
- break;
- case 4:
- rel = insn_fetch(s32, 4, c->eip);
- break;
- case 8:
- rel = insn_fetch(s64, 8, c->eip);
- break;
- default:
- DPRINTF("jnz: Invalid op_bytes\n");
- goto cannot_emulate;
- }
+ case 0x80 ... 0x8f: /* jnz rel, etc*/
if (test_cc(c->b, ctxt->eflags))
- jmp_rel(c, rel);
+ jmp_rel(c, c->src.val);
c->dst.type = OP_NONE;
break;
- }
case 0xa3:
bt: /* bt */
c->dst.type = OP_NONE;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.