[Qemu-devel] Invalid data memory access on qemu-ppc

[Ed Swierk]

I'm using the ppc-linux-user target to run processes in a Debian
Wheezy filesystem I built using multistrap. I built qemu from
yesterday's head of the git tree.

When I try to run a Python JSON database called jsonstore, I qemu-ppc
barfs with an "Invalid data memory access", with the invalid address
always being the lower 32 bits of guest_base (which I take to mean 0).

Here is an excerpt of qemu.log with in_asm enabled. I've included the
top and bottom, as well as a chunk from the middle where the guest
tries to execute the fcfid instruction (with no ill effects, at least
until the crash later on).

real_start=0x7f0468307000 real_size=0xf7000000
Reserved 0xf7000000 bytes of guest address space
host mmap_min_addr=0x10000
guest_base  0x7f0468307000
start    end      size     prot
10000000-1022e000 0022e000 r-x
1023d000-1029a000 0005d000 rw-
f678b000-f67ab000 00020000 r-x
f67ab000-f67ac000 00001000 ---
f67ac000-f67ae000 00002000 rw-
f67ae000-f67af000 00001000 ---
f67af000-f7000000 00851000 rw-
start_brk   0x00000000
end_code    0x1022d238
start_code  0x10000000
start_data  0x1023ded4
end_data    0x1028d99c
start_stack 0xf6fffa68
brk         0x10299da0
entry       0xf67a2f94
IN:
0xf67a2f94:  mr      r3,r1
0xf67a2f98:  li      r4,0
0xf67a2f9c:  addi    r1,r1,-16
0xf67a2fa0:  stw     r4,0(r1)
0xf67a2fa4:  bl      0xf678d2e0

...

IN:
0x0fa89a54:  cmpwi   cr7,r3,0
0x0fa89a58:  beq-    cr7,0xfa89a94

IN:
0x0fa89a94:  bl      0xfa89690

invalid/unsupported opcode: 3f - 0e - 1a (fc200e9c) 0fa89690 0
IN:
0x0fa89690:  fcfid   f1,f1

Invalid instruction
NIP 0fa89694   LR 0fa89a98 CTR 0fd28508 XER 20000000
MSR 02006040 HID0 00000000  HF 02006000 idx 0
TB 00000000 00000000
GPR00 000000000fa89a54 00000000f6ffe3c0 00000000f678b4a0 0000000000000000
GPR04 0000000000000000 000000000fc0ae34 0000000000000008 0000000000000020
GPR08 00000000ffffffc0 0000000000000000 000000001028d968 000000000fd28508
GPR12 0000000022282464 0000000010295894 000000001033acf0 0000000000000000
GPR16 00000000102f6fc0 000000001033acf0 0000000000000063 000000001028d968
GPR20 000000001033c780 0000000010290000 00000000f65077b8 000000001029da90
GPR24 00000000000000a4 0000000000000029 00000000f66fd0c0 00000000103578f0
GPR28 000000000fcaaa64 000000000fc0aec4 000000000fc08b08 000000000fc0ac70
CR 22282462  [ E  E  E  L  E  G  G  E  ]             RES ffffffff
FPR00 4018000000000000 4008000000000000 4330000080000002 4330000080000003
FPR04 fff8000000000233 41d44526a3400000 43300000d1149a8d 4330000000000000
FPR08 40c0e38000000000 43300000000021c7 fff80000000021c7 40c0000000000000
FPR12 4330000080000006 4018000000000000 0000000000000000 0000000000000000
FPR16 0000000000000000 0000000000000000 0000000000000000 0000000000000000
FPR20 0000000000000000 0000000000000000 0000000000000000 0000000000000000
FPR24 0000000000000000 0000000000000000 0000000000000000 0000000000000000
FPR28 0000000000000000 0000000000000000 0000000000000000 0000000000000000
FPSCR 00002000
IN:
0x0fa89810:  stwu    r1,-32(r1)
0x0fa89814:  mflr    r0
0x0fa89818:  bcl-    20,4*cr7+so,0xfa8981c

...

IN:
0x0f6de328:  li      r0,0
0x0f6de32c:  stw     r0,12(r27)
0x0f6de330:  lwz     r0,36(r1)
0x0f6de334:  lwz     r26,8(r1)
0x0f6de338:  mtlr    r0
0x0f6de33c:  lwz     r27,12(r1)
0x0f6de340:  lwz     r28,16(r1)
0x0f6de344:  lwz     r29,20(r1)
0x0f6de348:  lwz     r30,24(r1)
0x0f6de34c:  lwz     r31,28(r1)
0x0f6de350:  addi    r1,r1,32
0x0f6de354:  blr

IN:
0x0f6dcda8:  lwz     r3,16(r29)
0x0f6dcdac:  bl      0xf6de860

IN:
0x0f6de860:  lwz     r11,-32304(r30)
0x0f6de864:  mtctr   r11
0x0f6de868:  bctr

Invalid data memory access: 0x68307000
NIP 00000000   LR 0f6dcdb0 CTR 00000000 XER 20000000
MSR 02006040 HID0 00000000  HF 02006000 idx 0
TB 00000000 00000000
GPR00 000000000f6dcda8 00000000f6ffe210 00000000f678b4a0 00000000103cb648
GPR04 0000000000000016 0000000000000002 00000000100eb470 000000000f6de0c4
GPR08 0000000000000001 0000000000000002 0000000000000002 0000000000000000
GPR12 0000000048444448 0000000010295894 000000001029a0b8 0000000000000000
GPR16 00000000107b1190 00000000f66e6110 0000000000000000 000000001028d968
GPR20 0000000010774548 0000000010290000 0000000010782b60 00000000107a2b40
GPR24 0000000000000000 000000001029a0b8 000000001031cc58 0000000000000790
GPR28 00000000ffffffff 0000000010779830 000000000f6f77c4 000000000f6ef9b4
CR 24482422  [ E  G  G  L  E  G  E  E  ]             RES ffffffff
FPR00 0000000000000000 0000000000000000 4330000080000000 43300000d1158120
FPR04 43300000800f18b7 41d44526a5c00000 43300000d1149a97 4330000000000000
FPR08 0000000000000000 4330000000000000 3f320b5c27000000 4330000080000000
FPR12 4330000080010000 0000000000000000 0000000000000000 0000000000000000
FPR16 0000000000000000 0000000000000000 0000000000000000 0000000000000000
FPR20 0000000000000000 0000000000000000 0000000000000000 0000000000000000
FPR24 0000000000000000 0000000000000000 0000000000000000 0000000000000000
FPR28 0000000000000000 0000000000000000 0000000000000000 0000000000000000
FPSCR 82002000

Any clues what could be going on?

Thanks.