From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:52402 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752579AbdGCL2J (ORCPT ); Mon, 3 Jul 2017 07:28:09 -0400 Subject: Patch "virtio_net: fix PAGE_SIZE > 64k" has been added to the 4.4-stable tree To: mst@redhat.com, alexander.levin@verizon.com, davem@davemloft.net, gregkh@linuxfoundation.org, john.fastabend@gmail.com Cc: , From: Date: Mon, 03 Jul 2017 13:28:06 +0200 Message-ID: <149908128623088@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled virtio_net: fix PAGE_SIZE > 64k to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: virtio_net-fix-page_size-64k.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Mon Jul 3 13:22:16 CEST 2017 From: "Michael S. Tsirkin" Date: Mon, 23 Jan 2017 21:37:52 +0200 Subject: virtio_net: fix PAGE_SIZE > 64k From: "Michael S. Tsirkin" [ Upstream commit d0fa28f00052391b5df328f502fbbdd4444938b7 ] I don't have any guests with PAGE_SIZE > 64k but the code seems to be clearly broken in that case as PAGE_SIZE / MERGEABLE_BUFFER_ALIGN will need more than 8 bit and so the code in mergeable_ctx_to_buf_address does not give us the actual true size. Cc: John Fastabend Signed-off-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/net/virtio_net.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -47,8 +47,16 @@ module_param(gso, bool, 0444); */ DECLARE_EWMA(pkt_len, 1, 64) +/* With mergeable buffers we align buffer address and use the low bits to + * encode its true size. Buffer size is up to 1 page so we need to align to + * square root of page size to ensure we reserve enough bits to encode the true + * size. + */ +#define MERGEABLE_BUFFER_MIN_ALIGN_SHIFT ((PAGE_SHIFT + 1) / 2) + /* Minimum alignment for mergeable packet buffers. */ -#define MERGEABLE_BUFFER_ALIGN max(L1_CACHE_BYTES, 256) +#define MERGEABLE_BUFFER_ALIGN max(L1_CACHE_BYTES, \ + 1 << MERGEABLE_BUFFER_MIN_ALIGN_SHIFT) #define VIRTNET_DRIVER_VERSION "1.0.0" Patches currently in stable-queue which might be from mst@redhat.com are queue-4.4/virtio_console-fix-a-crash-in-config_work_handler.patch queue-4.4/virtio_net-fix-page_size-64k.patch