Re: [PATCH] softmmu/memory: Log invalid memory accesses

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Oct 05, 2020 at 05:27:25PM +0200, Philippe Mathieu-Daudé wrote:
> Log invalid memory accesses with as GUEST_ERROR.
> 
> This is particularly useful since commit 5d971f9e67 which reverted
> ("memory: accept mismatching sizes in memory_region_access_valid").
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

Paolo's tree I assume?

> ---
>  softmmu/memory.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/softmmu/memory.c b/softmmu/memory.c
> index fa280a19f7..403ff3abc9 100644
> --- a/softmmu/memory.c
> +++ b/softmmu/memory.c
> @@ -14,6 +14,7 @@
>   */
>  
>  #include "qemu/osdep.h"
> +#include "qemu/log.h"
>  #include "qapi/error.h"
>  #include "cpu.h"
>  #include "exec/memory.h"
> @@ -1353,10 +1354,18 @@ bool memory_region_access_valid(MemoryRegion *mr,
>  {
>      if (mr->ops->valid.accepts
>          && !mr->ops->valid.accepts(mr->opaque, addr, size, is_write, attrs)) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "Invalid access at addr "
> +                                       "0x%" HWADDR_PRIX ", size %u, "
> +                                       "region '%s', reason: rejected\n",
> +                      addr, size, memory_region_name(mr));
>          return false;
>      }
>  
>      if (!mr->ops->valid.unaligned && (addr & (size - 1))) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "Invalid access at addr "
> +                                       "0x%" HWADDR_PRIX ", size %u, "
> +                                       "region '%s', reason: unaligned\n",
> +                      addr, size, memory_region_name(mr));
>          return false;
>      }
>  
> @@ -1367,6 +1376,13 @@ bool memory_region_access_valid(MemoryRegion *mr,
>  
>      if (size > mr->ops->valid.max_access_size
>          || size < mr->ops->valid.min_access_size) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "Invalid access at addr "
> +                                       "0x%" HWADDR_PRIX ", size %u, "
> +                                       "region '%s', reason: invalid size "
> +                                       "(min:%u max:%u)\n",
> +                      addr, size, memory_region_name(mr),
> +                      mr->ops->valid.min_access_size,
> +                      mr->ops->valid.max_access_size);
>          return false;
>      }
>      return true;
> -- 
> 2.26.2