|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] x86emul: New return code for unimplemented instruction
commit 63e49e966fafc4057deb8968b63b2bbe9bb6fd1e
Author: Petre Pircalabu <ppircalabu@xxxxxxxxxxxxxxx>
AuthorDate: Mon Oct 2 16:04:54 2017 +0100
Commit: George Dunlap <george.dunlap@xxxxxxxxxx>
CommitDate: Mon Oct 2 16:04:54 2017 +0100
x86emul: New return code for unimplemented instruction
Enforce the distinction between an instruction not implemented by the
emulator and the failure to emulate that instruction by defining a new
return code, X86EMUL_UNIMPLEMENTED.
This value should only be returned by the core emulator when a valid
opcode is found but the execution logic for that instruction is missing.
It should NOT be returned by any of the x86_emulate_ops callbacks.
e.g. hvm_process_io_intercept should not return X86EMUL_UNIMPLEMENTED.
The return value of this function depends on either the return code of
one of the hvm_io_ops handlers (read/write) or the value returned by
hvm_copy_guest_from_phys / hvm_copy_to_guest_phys.
Similary, none of this functions should return X86EMUL_UNIMPLEMENTED.
- hvm_io_intercept
- hvmemul_do_io
- hvm_send_buffered_ioreq
- hvm_send_ioreq
- hvm_broadcast_ioreq
- hvmemul_do_io_buffer
- hvmemul_validate
Also the behavior of hvm_emulate_one_insn and vmx_realmode_emulate_one
was modified to generate an Invalid Opcode trap when X86EMUL_UNRECOGNIZED
is returned by the emulator instead of just crash the domain.
Signed-off-by: Petre Pircalabu <ppircalabu@xxxxxxxxxxxxxxx>
Reviewed-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxx>
---
xen/arch/x86/hvm/emulate.c | 12 ++++++++
xen/arch/x86/hvm/hvm.c | 1 +
xen/arch/x86/hvm/io.c | 5 ++++
xen/arch/x86/hvm/vmx/realmode.c | 9 ++++++
xen/arch/x86/mm/shadow/multi.c | 2 +-
xen/arch/x86/x86_emulate/x86_emulate.c | 51 +++++++++++++++++++---------------
xen/arch/x86/x86_emulate/x86_emulate.h | 17 ++++++++++++
7 files changed, 74 insertions(+), 23 deletions(-)
diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index cc874ce..385fe1e 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -284,10 +284,15 @@ static int hvmemul_do_io(
}
break;
}
+ case X86EMUL_UNIMPLEMENTED:
+ ASSERT_UNREACHABLE();
+ /* Fall-through */
default:
BUG();
}
+ ASSERT(rc != X86EMUL_UNIMPLEMENTED);
+
if ( rc != X86EMUL_OKAY )
return rc;
@@ -313,6 +318,9 @@ static int hvmemul_do_io_buffer(
rc = hvmemul_do_io(is_mmio, addr, reps, size, dir, df, 0,
(uintptr_t)buffer);
+
+ ASSERT(rc != X86EMUL_UNIMPLEMENTED);
+
if ( rc == X86EMUL_UNHANDLEABLE && dir == IOREQ_READ )
memset(buffer, 0xff, size);
@@ -405,6 +413,8 @@ static int hvmemul_do_io_addr(
rc = hvmemul_do_io(is_mmio, addr, &count, size, dir, df, 1,
ram_gpa);
+ ASSERT(rc != X86EMUL_UNIMPLEMENTED);
+
if ( rc == X86EMUL_OKAY )
v->arch.hvm_vcpu.hvm_io.mmio_retry = (count < *reps);
@@ -2045,6 +2055,7 @@ int hvm_emulate_one_mmio(unsigned long mfn, unsigned long
gla)
switch ( rc )
{
case X86EMUL_UNHANDLEABLE:
+ case X86EMUL_UNIMPLEMENTED:
hvm_dump_emulation_state(XENLOG_G_WARNING, "MMCFG", &ctxt);
break;
case X86EMUL_EXCEPTION:
@@ -2102,6 +2113,7 @@ void hvm_emulate_one_vm_event(enum emul_kind kind,
unsigned int trapnr,
* consistent with X86EMUL_RETRY.
*/
return;
+ case X86EMUL_UNIMPLEMENTED:
case X86EMUL_UNHANDLEABLE:
hvm_dump_emulation_state(XENLOG_G_DEBUG, "Mem event", &ctx);
hvm_inject_hw_exception(trapnr, errcode);
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 887f0e5..b0a46d7 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -3735,6 +3735,7 @@ void hvm_ud_intercept(struct cpu_user_regs *regs)
switch ( hvm_emulate_one(&ctxt) )
{
case X86EMUL_UNHANDLEABLE:
+ case X86EMUL_UNIMPLEMENTED:
hvm_inject_hw_exception(TRAP_invalid_op, X86_EVENT_NO_EC);
break;
case X86EMUL_EXCEPTION:
diff --git a/xen/arch/x86/hvm/io.c b/xen/arch/x86/hvm/io.c
index 1ddcaba..508e28f 100644
--- a/xen/arch/x86/hvm/io.c
+++ b/xen/arch/x86/hvm/io.c
@@ -99,6 +99,11 @@ bool hvm_emulate_one_insn(hvm_emulate_validate_t *validate,
const char *descr)
hvm_dump_emulation_state(XENLOG_G_WARNING, descr, &ctxt);
return false;
+ case X86EMUL_UNRECOGNIZED:
+ hvm_dump_emulation_state(XENLOG_G_WARNING, descr, &ctxt);
+ hvm_inject_hw_exception(TRAP_invalid_op, X86_EVENT_NO_EC);
+ break;
+
case X86EMUL_EXCEPTION:
hvm_inject_event(&ctxt.ctxt.event);
break;
diff --git a/xen/arch/x86/hvm/vmx/realmode.c b/xen/arch/x86/hvm/vmx/realmode.c
index 12d43ad..b73fc80 100644
--- a/xen/arch/x86/hvm/vmx/realmode.c
+++ b/xen/arch/x86/hvm/vmx/realmode.c
@@ -112,6 +112,15 @@ void vmx_realmode_emulate_one(struct hvm_emulate_ctxt
*hvmemul_ctxt)
goto fail;
}
+ if ( rc == X86EMUL_UNRECOGNIZED )
+ {
+ gdprintk(XENLOG_ERR, "Unrecognized insn.\n");
+ if ( curr->arch.hvm_vcpu.guest_cr[0] & X86_CR0_PE )
+ goto fail;
+
+ realmode_deliver_exception(TRAP_invalid_op, 0, hvmemul_ctxt);
+ }
+
if ( rc == X86EMUL_EXCEPTION )
{
if ( unlikely(curr->domain->debugger_attached) &&
diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
index 8d4f244..2557e21 100644
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -3488,7 +3488,7 @@ static int sh_page_fault(struct vcpu *v,
* would be a good unshadow hint. If we *do* decide to unshadow-on-fault
* then it must be 'failable': we cannot require the unshadow to succeed.
*/
- if ( r == X86EMUL_UNHANDLEABLE )
+ if ( r == X86EMUL_UNHANDLEABLE || r == X86EMUL_UNIMPLEMENTED )
{
perfc_incr(shadow_fault_emulate_failed);
#if SHADOW_OPTIMIZATIONS & SHOPT_FAST_EMULATION
diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c
b/xen/arch/x86/x86_emulate/x86_emulate.c
index ff1a401..a68676c 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -848,7 +848,8 @@ do{ asm volatile (
\
stub.func); \
generate_exception_if(res_.fields.trapnr == EXC_UD, EXC_UD); \
domain_crash(current->domain); \
- goto cannot_emulate; \
+ rc = X86EMUL_UNHANDLEABLE; \
+ goto done; \
} \
} while (0)
#else
@@ -2585,7 +2586,7 @@ x86_decode(
d = twobyte_table[0x3a].desc;
break;
default:
- rc = X86EMUL_UNHANDLEABLE;
+ rc = X86EMUL_UNRECOGNIZED;
goto done;
}
}
@@ -2599,7 +2600,7 @@ x86_decode(
}
else
{
- rc = X86EMUL_UNHANDLEABLE;
+ rc = X86EMUL_UNRECOGNIZED;
goto done;
}
@@ -2879,7 +2880,7 @@ x86_decode(
default:
ASSERT_UNREACHABLE();
- return X86EMUL_UNHANDLEABLE;
+ return X86EMUL_UNIMPLEMENTED;
}
if ( ea.type == OP_MEM )
@@ -4193,7 +4194,7 @@ x86_emulate(
break;
case 4: /* fldenv - TODO */
state->fpu_ctrl = true;
- goto cannot_emulate;
+ goto unimplemented_insn;
case 5: /* fldcw m2byte */
state->fpu_ctrl = true;
if ( (rc = ops->read(ea.mem.seg, ea.mem.off, &src.val,
@@ -4204,7 +4205,7 @@ x86_emulate(
break;
case 6: /* fnstenv - TODO */
state->fpu_ctrl = true;
- goto cannot_emulate;
+ goto unimplemented_insn;
case 7: /* fnstcw m2byte */
state->fpu_ctrl = true;
emulate_fpu_insn_memdst("fnstcw", dst.val);
@@ -4440,7 +4441,7 @@ x86_emulate(
case 4: /* frstor - TODO */
case 6: /* fnsave - TODO */
state->fpu_ctrl = true;
- goto cannot_emulate;
+ goto unimplemented_insn;
case 7: /* fnstsw m2byte */
state->fpu_ctrl = true;
emulate_fpu_insn_memdst("fnstsw", dst.val);
@@ -5199,7 +5200,7 @@ x86_emulate(
#undef _GRP7
default:
- goto cannot_emulate;
+ goto unimplemented_insn;
}
break;
}
@@ -6197,7 +6198,7 @@ x86_emulate(
/* vpsll{w,d} $imm8,{x,y}mm,{x,y}mm */
break;
default:
- goto cannot_emulate;
+ goto unrecognized_insn;
}
simd_0f_shift_imm:
generate_exception_if(ea.type != OP_REG, EXC_UD);
@@ -6245,7 +6246,7 @@ x86_emulate(
case 6: /* psllq $imm8,mm */
goto simd_0f_shift_imm;
}
- goto cannot_emulate;
+ goto unrecognized_insn;
case X86EMUL_OPC_66(0x0f, 0x73):
case X86EMUL_OPC_VEX_66(0x0f, 0x73):
@@ -6261,7 +6262,7 @@ x86_emulate(
/* vpslldq $imm8,{x,y}mm,{x,y}mm */
goto simd_0f_shift_imm;
}
- goto cannot_emulate;
+ goto unrecognized_insn;
case X86EMUL_OPC(0x0f, 0x77): /* emms */
case X86EMUL_OPC_VEX(0x0f, 0x77): /* vzero{all,upper} */
@@ -6325,7 +6326,7 @@ x86_emulate(
case 0: /* extrq $imm8,$imm8,xmm */
break;
default:
- goto cannot_emulate;
+ goto unrecognized_insn;
}
/* fall through */
case X86EMUL_OPC_F2(0x0f, 0x78): /* insertq $imm8,$imm8,xmm,xmm */
@@ -6520,7 +6521,7 @@ x86_emulate(
goto done;
break;
default:
- goto cannot_emulate;
+ goto unimplemented_insn;
}
break;
@@ -6536,7 +6537,7 @@ x86_emulate(
vcpu_must_have(avx);
goto stmxcsr;
}
- goto cannot_emulate;
+ goto unrecognized_insn;
case X86EMUL_OPC_F3(0x0f, 0xae): /* Grp15 */
fail_if(modrm_mod != 3);
@@ -6779,10 +6780,10 @@ x86_emulate(
switch ( modrm_reg & 7 )
{
default:
- goto cannot_emulate;
+ goto unrecognized_insn;
-#ifdef HAVE_GAS_RDRAND
case 6: /* rdrand */
+#ifdef HAVE_GAS_RDRAND
generate_exception_if(rep_prefix(), EXC_UD);
host_and_vcpu_must_have(rdrand);
dst = ea;
@@ -6807,6 +6808,8 @@ x86_emulate(
if ( carry )
_regs.eflags |= X86_EFLAGS_CF;
break;
+#else
+ goto unimplemented_insn;
#endif
case 7: /* rdseed / rdpid */
@@ -7361,7 +7364,7 @@ x86_emulate(
host_and_vcpu_must_have(bmi1);
break;
default:
- goto cannot_emulate;
+ goto unrecognized_insn;
}
generate_exception_if(vex.l, EXC_UD);
@@ -7672,7 +7675,7 @@ x86_emulate(
host_and_vcpu_must_have(tbm);
break;
default:
- goto cannot_emulate;
+ goto unrecognized_insn;
}
xop_09_rm_rv:
@@ -7706,7 +7709,7 @@ x86_emulate(
host_and_vcpu_must_have(tbm);
goto xop_09_rm_rv;
}
- goto cannot_emulate;
+ goto unrecognized_insn;
case X86EMUL_OPC_XOP(0a, 0x10): /* bextr imm,r/m,r */
{
@@ -7738,8 +7741,11 @@ x86_emulate(
}
default:
- cannot_emulate:
- rc = X86EMUL_UNHANDLEABLE;
+ unimplemented_insn:
+ rc = X86EMUL_UNIMPLEMENTED;
+ goto done;
+ unrecognized_insn:
+ rc = X86EMUL_UNRECOGNIZED;
goto done;
}
@@ -7791,7 +7797,8 @@ x86_emulate(
if ( (d & DstMask) != DstMem )
{
ASSERT_UNREACHABLE();
- goto cannot_emulate;
+ rc = X86EMUL_UNHANDLEABLE;
+ goto done;
}
break;
}
diff --git a/xen/arch/x86/x86_emulate/x86_emulate.h
b/xen/arch/x86/x86_emulate/x86_emulate.h
index 4ddf111..0c8c80a 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.h
+++ b/xen/arch/x86/x86_emulate/x86_emulate.h
@@ -133,6 +133,23 @@ struct x86_emul_fpu_aux {
* Undefined behavior when used anywhere else.
*/
#define X86EMUL_DONE 4
+ /*
+ * Current instruction is not implemented by the emulator.
+ * This value should only be returned by the core emulator when a valid
+ * opcode is found but the execution logic for that instruction is missing.
+ * It should NOT be returned by any of the x86_emulate_ops callbacks.
+ */
+#define X86EMUL_UNIMPLEMENTED 5
+ /*
+ * The current instruction's opcode is not valid.
+ * If this error code is returned by a function, an #UD trap should be
+ * raised by the final consumer of it.
+ *
+ * TODO: For the moment X86EMUL_UNRECOGNIZED and X86EMUL_UNIMPLEMENTED
+ * can be used interchangeably therefore raising an #UD trap is not
+ * strictly expected for now.
+ */
+#define X86EMUL_UNRECOGNIZED X86EMUL_UNIMPLEMENTED
/* FPU sub-types which may be requested via ->get_fpu(). */
enum x86_emulate_fpu_type {
--
generated by git-patchbot for /home/xen/git/xen.git#master
_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxx
https://lists.xenproject.org/xen-changelog
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |