On 17/07/19 08:06, tony.ngu...@bt.com wrote:
> +
> +static inline MemOp MEMOP(unsigned size)
> +{
> + switch (size) {
> + case 1:
> + return MO_8;
> + case 2:
> + return MO_16;
> + case 4:
> + return MO_32;
> + case 8:
> + return MO_64;
> + default:
> + g_assert_not_reached();
> + }
> +}
FWIW, this is just "ctz(size)".
My main concern is that MO_BE/MO_LE/MO_TE do not really apply to the
memory.c paths. MO_BSWAP is never passed into the MemOp, even if target
endianness != host endianness.
Therefore, you could return MO_TE | MO_{8,16,32,64} from this function,
and change memory_region_endianness_inverted to test
HOST_WORDS_BIGENDIAN instead of TARGET_WORDS_BIGENDIAN. Then the two
MO_BSWAPs (one from MO_TE, one from adjust_endianness because
memory_region_endianness_inverted returns true) cancel out if the
memory region's endianness is the same as the host's but different
from the target's.
Some care is needed in virtio_address_space_write and zpci_write_bar. I
think the latter is okay, while the former could do something like this:
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index ce928f2429..61885f020c 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -541,16 +541,16 @@ 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;
}
- memory_region_dispatch_write(mr, addr, val, len, MEMTXATTRS_UNSPECIFIED);
+ memory_region_dispatch_write(mr, addr, val, size_memop(len) & ~MO_BSWAP,
MEMTXATTRS_UNSPECIFIED);
}
static void
Paolo
