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Commit 0934ac9d authored by Mohammed Gamal's avatar Mohammed Gamal Committed by Avi Kivity
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KVM: x86 emulator: Add 'push/pop sreg' instructions 



[avi: avoid buffer overflow]

Signed-off-by: default avatarMohammed Gamal <m.gamal005@gmail.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 45ec431c

arch/x86/kvm/emulate.c

+101 −6
Original line number Diff line number Diff line
@@ -92,19 +92,22 @@ static u32 opcode_table[256] = { 
	/* 0x00 - 0x07 */

	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,

	ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,

	ByteOp | DstAcc | SrcImm, DstAcc | SrcImm, 0, 0,

	ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,

	ImplicitOps | Stack, ImplicitOps | Stack,

	/* 0x08 - 0x0F */

	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,

	ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,

	0, 0, 0, 0,

	0, 0, ImplicitOps | Stack, 0,

	/* 0x10 - 0x17 */

	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,

	ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,

	ByteOp | DstAcc | SrcImm, DstAcc | SrcImm, 0, 0,

	ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,

	ImplicitOps | Stack, ImplicitOps | Stack,

	/* 0x18 - 0x1F */

	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,

	ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,

	ByteOp | DstAcc | SrcImm, DstAcc | SrcImm, 0, 0,

	ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,

	ImplicitOps | Stack, ImplicitOps | Stack,

	/* 0x20 - 0x27 */

	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,

	ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
@@ -244,11 +247,13 @@ 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,

	DstMem | SrcReg | Src2ImmByte | ModRM,

	DstMem | SrcReg | Src2CL | ModRM,

	ModRM, 0,
@@ -1186,6 +1191,32 @@ static int emulate_pop(struct x86_emulate_ctxt *ctxt, 
	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, 1, seg);

	return rc;

}



static inline int emulate_grp1a(struct x86_emulate_ctxt *ctxt,

				struct x86_emulate_ops *ops)

{
@@ -1707,18 +1738,66 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
	      add:		/* add */

		emulate_2op_SrcV("add", c->src, c->dst, ctxt->eflags);

		break;

	case 0x06:		/* push es */

		if (ctxt->mode == X86EMUL_MODE_PROT64)

			goto cannot_emulate;



		emulate_push_sreg(ctxt, VCPU_SREG_ES);

		break;

	case 0x07:		/* pop es */

                if (ctxt->mode == X86EMUL_MODE_PROT64)

                        goto cannot_emulate;



		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 */

                if (ctxt->mode == X86EMUL_MODE_PROT64)

                        goto cannot_emulate;



		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 */

                if (ctxt->mode == X86EMUL_MODE_PROT64)

                        goto cannot_emulate;



		emulate_push_sreg(ctxt, VCPU_SREG_SS);

		break;

	case 0x17:		/* pop ss */

                if (ctxt->mode == X86EMUL_MODE_PROT64)

                        goto cannot_emulate;



		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 */

                if (ctxt->mode == X86EMUL_MODE_PROT64)

                        goto cannot_emulate;



		emulate_push_sreg(ctxt, VCPU_SREG_DS);

		break;

	case 0x1f:		/* pop ds */

                if (ctxt->mode == X86EMUL_MODE_PROT64)

                        goto cannot_emulate;



		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);
@@ -2297,6 +2376,14 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
			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 +2395,14 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
	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 */