From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60175) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eFY3M-0001iB-Ez for qemu-devel@nongnu.org; Thu, 16 Nov 2017 23:14:57 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eFY3J-0001mD-AW for qemu-devel@nongnu.org; Thu, 16 Nov 2017 23:14:56 -0500 Date: Fri, 17 Nov 2017 06:14:48 +0200 From: "Michael S. Tsirkin" Message-ID: <20171117061341-mutt-send-email-mst@kernel.org> References: <1510867014-13423-1-git-send-email-thuth@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1510867014-13423-1-git-send-email-thuth@redhat.com> Subject: Re: [Qemu-devel] [PATCH for-2.11] hw/net/eepro100: Fix endianness problem on big endian hosts List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth Cc: qemu-devel@nongnu.org, Jason Wang , Stefan Weil , Michael Nawrocki , qemu-s390x@nongnu.org On Thu, Nov 16, 2017 at 10:16:54PM +0100, Thomas Huth wrote: > Since commit 1865e288a823c764cd4344d ("Fix eepro100 simple transmission > mode"), the test/pxe-test is broken for the eepro100 device on big > endian hosts. However, it seems like that commit did not introduce the > problem, but just uncovered it: The EEPRO100State->tx.tbd_array_addr and > EEPRO100State->tx.tcb_bytes fields are already in host byte order, since > they have already been byte-swapped in the read_cb() function. > Thus byte-swapping them in tx_command() again results in the wrong > endianness. Removing the byte-swapping here fixes the pxe-test. > > Signed-off-by: Thomas Huth Reviewed-by: Michael S. Tsirkin Thomas, how about adding sparse endian-ness annotations a la le32 in Linux? We could then use static checkers to catch these bugs at build time. > --- > hw/net/eepro100.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/hw/net/eepro100.c b/hw/net/eepro100.c > index a63ed2c..03e00f7 100644 > --- a/hw/net/eepro100.c > +++ b/hw/net/eepro100.c > @@ -756,8 +756,8 @@ static void read_cb(EEPRO100State *s) > > static void tx_command(EEPRO100State *s) > { > - uint32_t tbd_array = le32_to_cpu(s->tx.tbd_array_addr); > - uint16_t tcb_bytes = (le16_to_cpu(s->tx.tcb_bytes) & 0x3fff); > + uint32_t tbd_array = s->tx.tbd_array_addr; > + uint16_t tcb_bytes = s->tx.tcb_bytes & 0x3fff; > /* Sends larger than MAX_ETH_FRAME_SIZE are allowed, up to 2600 bytes. */ > uint8_t buf[2600]; > uint16_t size = 0; > -- > 1.8.3.1