Re: [PATCH 1/2] hw/misc/grlib_ahb_apb_pnp: Avoid crash when writing to PnP registers

[Laurent Vivier]

Le 25/10/2019 à 13:01, Philippe Mathieu-Daudé a écrit :
> Guests can crash QEMU when writting to PnP registers:
> 
>   $ echo 'writeb 0x800ff042 69' | qemu-system-sparc -M leon3_generic -S -bios 
> /etc/magic -qtest stdio
>   [I 1571938309.932255] OPENED
>   [R +0.063474] writeb 0x800ff042 69
>   Segmentation fault (core dumped)
> 
>   (gdb) bt
>   #0  0x0000000000000000 in  ()
>   #1  0x0000555f4bcdf0bc in memory_region_write_with_attrs_accessor 
> (mr=0x555f4d7be8c0, addr=66, value=0x7fff07d00f08, size=1, shift=0, mask=255, 
> attrs=...) at memory.c:503
>   #2  0x0000555f4bcdf185 in access_with_adjusted_size (addr=66, 
> value=0x7fff07d00f08, size=1, access_size_min=1, access_size_max=4, 
> access_fn=0x555f4bcdeff4 <memory_region_write_with_attrs_accessor>, 
> mr=0x555f4d7be8c0, attrs=...) at memory.c:539
>   #3  0x0000555f4bce2243 in memory_region_dispatch_write (mr=0x555f4d7be8c0, 
> addr=66, data=69, op=MO_8, attrs=...) at memory.c:1489
>   #4  0x0000555f4bc80b20 in flatview_write_continue (fv=0x555f4d92c400, 
> addr=2148528194, attrs=..., buf=0x7fff07d01120 "E", len=1, addr1=66, l=1, 
> mr=0x555f4d7be8c0) at exec.c:3161
>   #5  0x0000555f4bc80c65 in flatview_write (fv=0x555f4d92c400, 
> addr=2148528194, attrs=..., buf=0x7fff07d01120 "E", len=1) at exec.c:3201
>   #6  0x0000555f4bc80fb0 in address_space_write (as=0x555f4d7aa460, 
> addr=2148528194, attrs=..., buf=0x7fff07d01120 "E", len=1) at exec.c:3291
>   #7  0x0000555f4bc8101d in address_space_rw (as=0x555f4d7aa460, 
> addr=2148528194, attrs=..., buf=0x7fff07d01120 "E", len=1, is_write=true) at 
> exec.c:3301
>   #8  0x0000555f4bcdb388 in qtest_process_command (chr=0x555f4c2ed7e0 
> <qtest_chr>, words=0x555f4db0c5d0) at qtest.c:432
> 
> Instead of crashing, log the access as unimplemented.
> 
> Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
> ---
>  hw/misc/grlib_ahb_apb_pnp.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/hw/misc/grlib_ahb_apb_pnp.c b/hw/misc/grlib_ahb_apb_pnp.c
> index 7338461694..f3c015d2c3 100644
> --- a/hw/misc/grlib_ahb_apb_pnp.c
> +++ b/hw/misc/grlib_ahb_apb_pnp.c
> @@ -22,6 +22,7 @@
>   */
>  
>  #include "qemu/osdep.h"
> +#include "qemu/log.h"
>  #include "hw/sysbus.h"
>  #include "hw/misc/grlib_ahb_apb_pnp.h"
>  
> @@ -231,8 +232,15 @@ static uint64_t grlib_apb_pnp_read(void *opaque, hwaddr 
> offset, unsigned size)
>      return apb_pnp->regs[offset >> 2];
>  }
>  
> +static void grlib_apb_pnp_write(void *opaque, hwaddr addr,
> +                                uint64_t val, unsigned size)
> +{
> +    qemu_log_mask(LOG_UNIMP, "%s not implemented\n", __func__);
> +}
> +
>  static const MemoryRegionOps grlib_apb_pnp_ops = {
>      .read       = grlib_apb_pnp_read,
> +    .write      = grlib_apb_pnp_write,
>      .endianness = DEVICE_BIG_ENDIAN,
>  };
>  
> 

Applied to my trivial-patches branch.

Thanks,
Laurent