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KVM: x86 emulator: use correct type for memory address in operands
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Currently we use a void pointer for memory addresses.  That's wrong since
these are guest virtual addresses which are not directly dereferencable by
the host.

Use the correct type, unsigned long.

Signed-off-by: Avi Kivity <avi@redhat.com>
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Avi Kivity committed Oct 24, 2010
1 parent 09ee57c commit 1a6440a
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Showing 2 changed files with 61 additions and 61 deletions.
5 changes: 4 additions & 1 deletion arch/x86/include/asm/kvm_emulate.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -156,7 +156,10 @@ struct operand {
unsigned long orig_val;
u64 orig_val64;
};
unsigned long *ptr;
union {
unsigned long *reg;
unsigned long mem;
} addr;
union {
unsigned long val;
u64 val64;
Expand Down
117 changes: 57 additions & 60 deletions arch/x86/kvm/emulate.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -489,20 +489,18 @@ static void *decode_register(u8 modrm_reg, unsigned long *regs,

static int read_descriptor(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
void *ptr,
ulong addr,
u16 *size, unsigned long *address, int op_bytes)
{
int rc;

if (op_bytes == 2)
op_bytes = 3;
*address = 0;
rc = ops->read_std((unsigned long)ptr, (unsigned long *)size, 2,
ctxt->vcpu, NULL);
rc = ops->read_std(addr, (unsigned long *)size, 2, ctxt->vcpu, NULL);
if (rc != X86EMUL_CONTINUE)
return rc;
rc = ops->read_std((unsigned long)ptr + 2, address, op_bytes,
ctxt->vcpu, NULL);
rc = ops->read_std(addr + 2, address, op_bytes, ctxt->vcpu, NULL);
return rc;
}

Expand Down Expand Up @@ -552,21 +550,21 @@ static void decode_register_operand(struct operand *op,
reg = (c->b & 7) | ((c->rex_prefix & 1) << 3);
op->type = OP_REG;
if ((c->d & ByteOp) && !inhibit_bytereg) {
op->ptr = decode_register(reg, c->regs, highbyte_regs);
op->val = *(u8 *)op->ptr;
op->addr.reg = decode_register(reg, c->regs, highbyte_regs);
op->val = *(u8 *)op->addr.reg;
op->bytes = 1;
} else {
op->ptr = decode_register(reg, c->regs, 0);
op->addr.reg = decode_register(reg, c->regs, 0);
op->bytes = c->op_bytes;
switch (op->bytes) {
case 2:
op->val = *(u16 *)op->ptr;
op->val = *(u16 *)op->addr.reg;
break;
case 4:
op->val = *(u32 *)op->ptr;
op->val = *(u32 *)op->addr.reg;
break;
case 8:
op->val = *(u64 *) op->ptr;
op->val = *(u64 *) op->addr.reg;
break;
}
}
Expand Down Expand Up @@ -976,38 +974,37 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt,
*/
switch (c->dst.bytes) {
case 1:
*(u8 *)c->dst.ptr = (u8)c->dst.val;
*(u8 *)c->dst.addr.reg = (u8)c->dst.val;
break;
case 2:
*(u16 *)c->dst.ptr = (u16)c->dst.val;
*(u16 *)c->dst.addr.reg = (u16)c->dst.val;
break;
case 4:
*c->dst.ptr = (u32)c->dst.val;
*c->dst.addr.reg = (u32)c->dst.val;
break; /* 64b: zero-ext */
case 8:
*c->dst.ptr = c->dst.val;
*c->dst.addr.reg = c->dst.val;
break;
}
break;
case OP_MEM:
if (c->lock_prefix)
rc = ops->cmpxchg_emulated(
(unsigned long)c->dst.ptr,
c->dst.addr.mem,
&c->dst.orig_val,
&c->dst.val,
c->dst.bytes,
&err,
ctxt->vcpu);
else
rc = ops->write_emulated(
(unsigned long)c->dst.ptr,
c->dst.addr.mem,
&c->dst.val,
c->dst.bytes,
&err,
ctxt->vcpu);
if (rc == X86EMUL_PROPAGATE_FAULT)
emulate_pf(ctxt,
(unsigned long)c->dst.ptr, err);
emulate_pf(ctxt, c->dst.addr.mem, err);
if (rc != X86EMUL_CONTINUE)
return rc;
break;
Expand All @@ -1029,8 +1026,8 @@ static inline void emulate_push(struct x86_emulate_ctxt *ctxt,
c->dst.bytes = c->op_bytes;
c->dst.val = c->src.val;
register_address_increment(c, &c->regs[VCPU_REGS_RSP], -c->op_bytes);
c->dst.ptr = (void *) register_address(c, ss_base(ctxt, ops),
c->regs[VCPU_REGS_RSP]);
c->dst.addr.mem = register_address(c, ss_base(ctxt, ops),
c->regs[VCPU_REGS_RSP]);
}

static int emulate_pop(struct x86_emulate_ctxt *ctxt,
Expand Down Expand Up @@ -2019,7 +2016,7 @@ static void string_addr_inc(struct x86_emulate_ctxt *ctxt, unsigned long base,
int df = (ctxt->eflags & EFLG_DF) ? -1 : 1;

register_address_increment(c, &c->regs[reg], df * op->bytes);
op->ptr = (unsigned long *)register_address(c, base, c->regs[reg]);
op->addr.mem = register_address(c, base, c->regs[reg]);
}

static int em_push(struct x86_emulate_ctxt *ctxt)
Expand Down Expand Up @@ -2456,17 +2453,17 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt)
if ((c->d & ModRM) && c->modrm_mod == 3) {
c->src.type = OP_REG;
c->src.val = c->modrm_val;
c->src.ptr = c->modrm_ptr;
c->src.addr.reg = c->modrm_ptr;
break;
}
c->src.type = OP_MEM;
c->src.ptr = (unsigned long *)c->modrm_ea;
c->src.addr.mem = c->modrm_ea;
c->src.val = 0;
break;
case SrcImm:
case SrcImmU:
c->src.type = OP_IMM;
c->src.ptr = (unsigned long *)c->eip;
c->src.addr.mem = c->eip;
c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
if (c->src.bytes == 8)
c->src.bytes = 4;
Expand Down Expand Up @@ -2499,7 +2496,7 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt)
case SrcImmByte:
case SrcImmUByte:
c->src.type = OP_IMM;
c->src.ptr = (unsigned long *)c->eip;
c->src.addr.mem = c->eip;
c->src.bytes = 1;
if ((c->d & SrcMask) == SrcImmByte)
c->src.val = insn_fetch(s8, 1, c->eip);
Expand All @@ -2509,19 +2506,19 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt)
case SrcAcc:
c->src.type = OP_REG;
c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
c->src.ptr = &c->regs[VCPU_REGS_RAX];
c->src.addr.reg = &c->regs[VCPU_REGS_RAX];
switch (c->src.bytes) {
case 1:
c->src.val = *(u8 *)c->src.ptr;
c->src.val = *(u8 *)c->src.addr.reg;
break;
case 2:
c->src.val = *(u16 *)c->src.ptr;
c->src.val = *(u16 *)c->src.addr.reg;
break;
case 4:
c->src.val = *(u32 *)c->src.ptr;
c->src.val = *(u32 *)c->src.addr.reg;
break;
case 8:
c->src.val = *(u64 *)c->src.ptr;
c->src.val = *(u64 *)c->src.addr.reg;
break;
}
break;
Expand All @@ -2532,20 +2529,20 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt)
case SrcSI:
c->src.type = OP_MEM;
c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
c->src.ptr = (unsigned long *)
c->src.addr.mem =
register_address(c, seg_override_base(ctxt, ops, c),
c->regs[VCPU_REGS_RSI]);
c->src.val = 0;
break;
case SrcImmFAddr:
c->src.type = OP_IMM;
c->src.ptr = (unsigned long *)c->eip;
c->src.addr.mem = c->eip;
c->src.bytes = c->op_bytes + 2;
insn_fetch_arr(c->src.valptr, c->src.bytes, c->eip);
break;
case SrcMemFAddr:
c->src.type = OP_MEM;
c->src.ptr = (unsigned long *)c->modrm_ea;
c->src.addr.mem = c->modrm_ea;
c->src.bytes = c->op_bytes + 2;
break;
}
Expand All @@ -2563,7 +2560,7 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt)
break;
case Src2ImmByte:
c->src2.type = OP_IMM;
c->src2.ptr = (unsigned long *)c->eip;
c->src2.addr.mem = c->eip;
c->src2.bytes = 1;
c->src2.val = insn_fetch(u8, 1, c->eip);
break;
Expand All @@ -2588,11 +2585,11 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt)
c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
c->dst.type = OP_REG;
c->dst.val = c->dst.orig_val = c->modrm_val;
c->dst.ptr = c->modrm_ptr;
c->dst.addr.reg = c->modrm_ptr;
break;
}
c->dst.type = OP_MEM;
c->dst.ptr = (unsigned long *)c->modrm_ea;
c->dst.addr.mem = c->modrm_ea;
if ((c->d & DstMask) == DstMem64)
c->dst.bytes = 8;
else
Expand All @@ -2601,34 +2598,34 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt)
if (c->d & BitOp) {
unsigned long mask = ~(c->dst.bytes * 8 - 1);

c->dst.ptr = (void *)c->dst.ptr +
c->dst.addr.mem = c->dst.addr.mem +
(c->src.val & mask) / 8;
}
break;
case DstAcc:
c->dst.type = OP_REG;
c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
c->dst.ptr = &c->regs[VCPU_REGS_RAX];
c->dst.addr.reg = &c->regs[VCPU_REGS_RAX];
switch (c->dst.bytes) {
case 1:
c->dst.val = *(u8 *)c->dst.ptr;
c->dst.val = *(u8 *)c->dst.addr.reg;
break;
case 2:
c->dst.val = *(u16 *)c->dst.ptr;
c->dst.val = *(u16 *)c->dst.addr.reg;
break;
case 4:
c->dst.val = *(u32 *)c->dst.ptr;
c->dst.val = *(u32 *)c->dst.addr.reg;
break;
case 8:
c->dst.val = *(u64 *)c->dst.ptr;
c->dst.val = *(u64 *)c->dst.addr.reg;
break;
}
c->dst.orig_val = c->dst.val;
break;
case DstDI:
c->dst.type = OP_MEM;
c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
c->dst.ptr = (unsigned long *)
c->dst.addr.mem =
register_address(c, es_base(ctxt, ops),
c->regs[VCPU_REGS_RDI]);
c->dst.val = 0;
Expand Down Expand Up @@ -2696,15 +2693,15 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
}

if (c->src.type == OP_MEM) {
rc = read_emulated(ctxt, ops, (unsigned long)c->src.ptr,
rc = read_emulated(ctxt, ops, c->src.addr.mem,
c->src.valptr, c->src.bytes);
if (rc != X86EMUL_CONTINUE)
goto done;
c->src.orig_val64 = c->src.val64;
}

if (c->src2.type == OP_MEM) {
rc = read_emulated(ctxt, ops, (unsigned long)c->src2.ptr,
rc = read_emulated(ctxt, ops, c->src2.addr.mem,
&c->src2.val, c->src2.bytes);
if (rc != X86EMUL_CONTINUE)
goto done;
Expand All @@ -2716,7 +2713,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)

if ((c->dst.type == OP_MEM) && !(c->d & Mov)) {
/* optimisation - avoid slow emulated read if Mov */
rc = read_emulated(ctxt, ops, (unsigned long)c->dst.ptr,
rc = read_emulated(ctxt, ops, c->dst.addr.mem,
&c->dst.val, c->dst.bytes);
if (rc != X86EMUL_CONTINUE)
goto done;
Expand Down Expand Up @@ -2880,16 +2877,16 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
/* Write back the register source. */
switch (c->dst.bytes) {
case 1:
*(u8 *) c->src.ptr = (u8) c->dst.val;
*(u8 *) c->src.addr.reg = (u8) c->dst.val;
break;
case 2:
*(u16 *) c->src.ptr = (u16) c->dst.val;
*(u16 *) c->src.addr.reg = (u16) c->dst.val;
break;
case 4:
*c->src.ptr = (u32) c->dst.val;
*c->src.addr.reg = (u32) c->dst.val;
break; /* 64b reg: zero-extend */
case 8:
*c->src.ptr = c->dst.val;
*c->src.addr.reg = c->dst.val;
break;
}
/*
Expand Down Expand Up @@ -2936,23 +2933,23 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
goto done;
break;
case 0x90: /* nop / xchg r8,rax */
if (c->dst.ptr == (unsigned long *)&c->regs[VCPU_REGS_RAX]) {
if (c->dst.addr.reg == &c->regs[VCPU_REGS_RAX]) {
c->dst.type = OP_NONE; /* nop */
break;
}
case 0x91 ... 0x97: /* xchg reg,rax */
c->src.type = OP_REG;
c->src.bytes = c->op_bytes;
c->src.ptr = (unsigned long *) &c->regs[VCPU_REGS_RAX];
c->src.val = *(c->src.ptr);
c->src.addr.reg = &c->regs[VCPU_REGS_RAX];
c->src.val = *(c->src.addr.reg);
goto xchg;
case 0x9c: /* pushf */
c->src.val = (unsigned long) ctxt->eflags;
emulate_push(ctxt, ops);
break;
case 0x9d: /* popf */
c->dst.type = OP_REG;
c->dst.ptr = (unsigned long *) &ctxt->eflags;
c->dst.addr.reg = &ctxt->eflags;
c->dst.bytes = c->op_bytes;
rc = emulate_popf(ctxt, ops, &c->dst.val, c->op_bytes);
if (rc != X86EMUL_CONTINUE)
Expand All @@ -2963,7 +2960,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
goto mov;
case 0xa6 ... 0xa7: /* cmps */
c->dst.type = OP_NONE; /* Disable writeback. */
DPRINTF("cmps: mem1=0x%p mem2=0x%p\n", c->src.ptr, c->dst.ptr);
DPRINTF("cmps: mem1=0x%p mem2=0x%p\n", c->src.addr.mem, c->dst.addr.mem);
goto cmp;
case 0xa8 ... 0xa9: /* test ax, imm */
goto test;
Expand All @@ -2982,7 +2979,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
break;
case 0xc3: /* ret */
c->dst.type = OP_REG;
c->dst.ptr = &c->eip;
c->dst.addr.reg = &c->eip;
c->dst.bytes = c->op_bytes;
goto pop_instruction;
case 0xc6 ... 0xc7: /* mov (sole member of Grp11) */
Expand Down Expand Up @@ -3184,7 +3181,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
c->dst.type = OP_NONE;
break;
case 2: /* lgdt */
rc = read_descriptor(ctxt, ops, c->src.ptr,
rc = read_descriptor(ctxt, ops, c->src.addr.mem,
&size, &address, c->op_bytes);
if (rc != X86EMUL_CONTINUE)
goto done;
Expand All @@ -3204,7 +3201,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
goto cannot_emulate;
}
} else {
rc = read_descriptor(ctxt, ops, c->src.ptr,
rc = read_descriptor(ctxt, ops, c->src.addr.mem,
&size, &address,
c->op_bytes);
if (rc != X86EMUL_CONTINUE)
Expand Down Expand Up @@ -3399,7 +3396,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
} else {
/* Failure: write the value we saw to EAX. */
c->dst.type = OP_REG;
c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX];
c->dst.addr.reg = (unsigned long *)&c->regs[VCPU_REGS_RAX];
}
break;
case 0xb3:
Expand Down

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