Re: [qemu-s390x] [Qemu-devel] [PATCH v6 20/26] memory: Access MemoryRegion with endianness

[Richard Henderson]

On 8/7/19 1:33 AM, address@hidden wrote:
> @@ -551,6 +551,7 @@ void virtio_address_space_write(VirtIOPCIProxy *proxy, 
> hwaddr addr,
>          /* As length is under guest control, handle illegal values. */
>          return;
>      }
> +    /* FIXME: memory_region_dispatch_write ignores MO_BSWAP.  */
>      memory_region_dispatch_write(mr, addr, val, size_memop(len),
>                                   MEMTXATTRS_UNSPECIFIED);
>  }

Here is an example of where Paolo is quite right -- you cannot simply add MO_TE
via size_memop().  In patch 22 we see

> @@ -542,16 +542,15 @@ void virtio_address_space_write(VirtIOPCIProxy *proxy, 
> hwaddr addr,
>          val = pci_get_byte(buf);
>          break;
>      case 2:
> -        val = cpu_to_le16(pci_get_word(buf));
> +        val = pci_get_word(buf);
>          break;
>      case 4:
> -        val = cpu_to_le32(pci_get_long(buf));
> +        val = pci_get_long(buf);
>          break;
>      default:
>          /* As length is under guest control, handle illegal values. */
>          return;
>      }
> -    /* FIXME: memory_region_dispatch_write ignores MO_BSWAP.  */
>      memory_region_dispatch_write(mr, addr, val, size_memop(len),
>                                   MEMTXATTRS_UNSPECIFIED);

This is a little-endian store -- MO_LE not MO_TE.


r~