From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH net] virtio-net: unbreak cusmed packet for small buffer XDP Date: Wed, 28 Jun 2017 06:31:39 +0300 Message-ID: <20170628063033-mutt-send-email-mst@kernel.org> References: <1498614843-8163-1-git-send-email-jasowang@redhat.com> <20170628050057-mutt-send-email-mst@kernel.org> <7068053c-50da-6779-5ff2-6588e01e616d@redhat.com> <20170628051555-mutt-send-email-mst@kernel.org> <69907228-fc1b-175f-f6cd-7ac332e318be@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Disposition: inline In-Reply-To: <69907228-fc1b-175f-f6cd-7ac332e318be@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Jason Wang Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org T24gV2VkLCBKdW4gMjgsIDIwMTcgYXQgMTA6NDU6MThBTSArMDgwMCwgSmFzb24gV2FuZyB3cm90 ZToKPiAKPiAKPiBPbiAyMDE35bm0MDbmnIgyOOaXpSAxMDoxNywgTWljaGFlbCBTLiBUc2lya2lu IHdyb3RlOgo+ID4gT24gV2VkLCBKdW4gMjgsIDIwMTcgYXQgMTA6MTQ6MzRBTSArMDgwMCwgSmFz b24gV2FuZyB3cm90ZToKPiA+ID4gCj4gPiA+IE9uIDIwMTflubQwNuaciDI45pelIDEwOjAyLCBN aWNoYWVsIFMuIFRzaXJraW4gd3JvdGU6Cj4gPiA+ID4gT24gV2VkLCBKdW4gMjgsIDIwMTcgYXQg MDk6NTQ6MDNBTSArMDgwMCwgSmFzb24gV2FuZyB3cm90ZToKPiA+ID4gPiA+IFdlIHNob3VsZCBh bGxvdyBjc3VtZWQgcGFja2V0IGZvciBzbWFsbCBidWZmZXIsIG90aGVyd2lzZSBYRFBfUEFTUwo+ ID4gPiA+ID4gd29uJ3Qgd29yayBjb3JyZWN0bHkuCj4gPiA+ID4gPiAKPiA+ID4gPiA+IEZpeGVz IGNvbW1pdCBiYjkxYWNjZjI3MzMgKCJ2aXJ0aW8tbmV0OiBYRFAgc3VwcG9ydCBmb3Igc21hbGwg YnVmZmVycyIpCj4gPiA+ID4gPiBTaWduZWQtb2ZmLWJ5OiBKYXNvbiBXYW5nIDxqYXNvd2FuZ0By ZWRoYXQuY29tPgo+ID4gPiA+IFRoZSBpc3N1ZSB3b3VsZCBiZSBWSVJUSU9fTkVUX0hEUl9GX0RB VEFfVkFMSUQgbWlnaHQgYmUgc2V0Lgo+ID4gPiA+IFdoYXQgZG8geW91IHRoaW5rPwo+ID4gPiBJ IHRoaW5rIGl0J3Mgc2FmZS4gRm9yIFhEUF9QQVNTLCBpdCB3b3JrIGxpa2UgaW4gdGhlIHBhc3Qu Cj4gPiBUaGF0J3MgdGhlIHBhcnQgSSBkb24ndCBnZXQuIFdpdGggREFUQV9WQUxJRCBjc3VtIGlu IHBhY2tldCBpcyB3cm9uZywgWERQCj4gPiB0b29scyBhc3N1bWUgaXQncyB2YWx1ZS4KPiAKPiBE QVRBX1ZBTElEIGlzIENIRUNLU1VNX1VOQ0VTU0FSWSBvbiB0aGUgaG9zdCwgYW5kIGFjY29yZGlu ZyB0byB0aGUgY29tbWVudAo+IGluIHNrYnVmZi5oCj4gCj4gCj4gIgo+ICAqICAgVGhlIGhhcmR3 YXJlIHlvdSdyZSBkZWFsaW5nIHdpdGggZG9lc24ndCBjYWxjdWxhdGUgdGhlIGZ1bGwgY2hlY2tz dW0KPiAgKiAgIChhcyBpbiBDSEVDS1NVTV9DT01QTEVURSksIGJ1dCBpdCBkb2VzIHBhcnNlIGhl YWRlcnMgYW5kIHZlcmlmeQo+IGNoZWNrc3Vtcwo+ICAqICAgZm9yIHNwZWNpZmljIHByb3RvY29s cy4gRm9yIHN1Y2ggcGFja2V0cyBpdCB3aWxsIHNldAo+IENIRUNLU1VNX1VOTkVDRVNTQVJZCj4g ICogICBpZiB0aGVpciBjaGVja3N1bXMgYXJlIG9rYXkuIHNrYi0+Y3N1bSBpcyBzdGlsbCB1bmRl ZmluZWQgaW4gdGhpcyBjYXNlCj4gICogICB0aG91Z2guIEEgZHJpdmVyIG9yIGRldmljZSBtdXN0 IG5ldmVyIG1vZGlmeSB0aGUgY2hlY2tzdW0gZmllbGQgaW4gdGhlCj4gICogICBwYWNrZXQgZXZl biBpZiBjaGVja3N1bSBpcyB2ZXJpZmllZC4KPiAiCj4gCj4gVGhlIGNzdW0gaXMgY29ycmVjdCBJ IGJlbGlldmU/Cj4gCj4gVGhhbmtzCgpUaGF0J3Mgb24gaW5wdXQuIEJ1dCBJIHRoaW5rIGZvciB0 dW4gaXQncyBvdXRwdXQsIHdoZXJlIHRoYXQgaXMgZXF1aXZhbGVudAp0byBDSEVDS1NVTV9OT05F CgoKPiA+IAo+ID4gPiBGb3IgWERQX1RYLCB3ZQo+ID4gPiB6ZXJvIHRoZSB2bmV0IGhlYWRlci4K PiA+IEFnYWluIFRYIG9mZmxvYWQgaXMgZGlzYWJsZWQsIHNvIHBhY2tldHMgd2lsbCBnbyBvdXQg d2l0aCBhbiBpbnZhbGlkCj4gPiBjaGVja3N1bS4KPiA+IAo+ID4gPiBGb3IgYWRqdXN0aW5nIGhl YWRlciwgWERQIHByb2cgc2hvdWxkIGRlYWwgd2l0aCBjc3VtLgo+ID4gPiAKPiA+ID4gVGhhbmtz Cj4gPiBUaGF0IHBhcnQgc2VlbXMgcmlnaHQuCj4gPiAKPiA+ID4gPiA+IC0tLQo+ID4gPiA+ID4g VGhlIHBhdGNoIGlzIG5lZWRlZCBmb3IgLXN0YWJsZS4KPiA+ID4gPiA+IC0tLQo+ID4gPiA+ID4g ICAgZHJpdmVycy9uZXQvdmlydGlvX25ldC5jIHwgMiArLQo+ID4gPiA+ID4gICAgMSBmaWxlIGNo YW5nZWQsIDEgaW5zZXJ0aW9uKCspLCAxIGRlbGV0aW9uKC0pCj4gPiA+ID4gPiAKPiA+ID4gPiA+ IGRpZmYgLS1naXQgYS9kcml2ZXJzL25ldC92aXJ0aW9fbmV0LmMgYi9kcml2ZXJzL25ldC92aXJ0 aW9fbmV0LmMKPiA+ID4gPiA+IGluZGV4IDE0M2Q4YTkuLjQ5OWZjYzkgMTAwNjQ0Cj4gPiA+ID4g PiAtLS0gYS9kcml2ZXJzL25ldC92aXJ0aW9fbmV0LmMKPiA+ID4gPiA+ICsrKyBiL2RyaXZlcnMv bmV0L3ZpcnRpb19uZXQuYwo+ID4gPiA+ID4gQEAgLTQxMyw3ICs0MTMsNyBAQCBzdGF0aWMgc3Ry dWN0IHNrX2J1ZmYgKnJlY2VpdmVfc21hbGwoc3RydWN0IG5ldF9kZXZpY2UgKmRldiwKPiA+ID4g PiA+ICAgIAkJdm9pZCAqb3JpZ19kYXRhOwo+ID4gPiA+ID4gICAgCQl1MzIgYWN0Owo+ID4gPiA+ ID4gLQkJaWYgKHVubGlrZWx5KGhkci0+aGRyLmdzb190eXBlIHx8IGhkci0+aGRyLmZsYWdzKSkK PiA+ID4gPiA+ICsJCWlmICh1bmxpa2VseShoZHItPmhkci5nc29fdHlwZSkpCj4gPiA+ID4gPiAg ICAJCQlnb3RvIGVycl94ZHA7Cj4gPiA+ID4gPiAgICAJCXhkcC5kYXRhX2hhcmRfc3RhcnQgPSBi dWYgKyBWSVJUTkVUX1JYX1BBRCArIHZpLT5oZHJfbGVuOwo+ID4gPiA+ID4gLS0gCj4gPiA+ID4g PiAyLjcuNApfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpW aXJ0dWFsaXphdGlvbiBtYWlsaW5nIGxpc3QKVmlydHVhbGl6YXRpb25AbGlzdHMubGludXgtZm91 bmRhdGlvbi5vcmcKaHR0cHM6Ly9saXN0cy5saW51eGZvdW5kYXRpb24ub3JnL21haWxtYW4vbGlz dGluZm8vdmlydHVhbGl6YXRpb24= From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753839AbdF1Dbs (ORCPT ); Tue, 27 Jun 2017 23:31:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46516 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752633AbdF1Dbl (ORCPT ); Tue, 27 Jun 2017 23:31:41 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 8DE9A883B1 Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=mst@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 8DE9A883B1 Date: Wed, 28 Jun 2017 06:31:39 +0300 From: "Michael S. Tsirkin" To: Jason Wang Cc: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net] virtio-net: unbreak cusmed packet for small buffer XDP Message-ID: <20170628063033-mutt-send-email-mst@kernel.org> References: <1498614843-8163-1-git-send-email-jasowang@redhat.com> <20170628050057-mutt-send-email-mst@kernel.org> <7068053c-50da-6779-5ff2-6588e01e616d@redhat.com> <20170628051555-mutt-send-email-mst@kernel.org> <69907228-fc1b-175f-f6cd-7ac332e318be@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <69907228-fc1b-175f-f6cd-7ac332e318be@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Wed, 28 Jun 2017 03:31:40 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 28, 2017 at 10:45:18AM +0800, Jason Wang wrote: > > > On 2017年06月28日 10:17, Michael S. Tsirkin wrote: > > On Wed, Jun 28, 2017 at 10:14:34AM +0800, Jason Wang wrote: > > > > > > On 2017年06月28日 10:02, Michael S. Tsirkin wrote: > > > > On Wed, Jun 28, 2017 at 09:54:03AM +0800, Jason Wang wrote: > > > > > We should allow csumed packet for small buffer, otherwise XDP_PASS > > > > > won't work correctly. > > > > > > > > > > Fixes commit bb91accf2733 ("virtio-net: XDP support for small buffers") > > > > > Signed-off-by: Jason Wang > > > > The issue would be VIRTIO_NET_HDR_F_DATA_VALID might be set. > > > > What do you think? > > > I think it's safe. For XDP_PASS, it work like in the past. > > That's the part I don't get. With DATA_VALID csum in packet is wrong, XDP > > tools assume it's value. > > DATA_VALID is CHECKSUM_UNCESSARY on the host, and according to the comment > in skbuff.h > > > " > * The hardware you're dealing with doesn't calculate the full checksum > * (as in CHECKSUM_COMPLETE), but it does parse headers and verify > checksums > * for specific protocols. For such packets it will set > CHECKSUM_UNNECESSARY > * if their checksums are okay. skb->csum is still undefined in this case > * though. A driver or device must never modify the checksum field in the > * packet even if checksum is verified. > " > > The csum is correct I believe? > > Thanks That's on input. But I think for tun it's output, where that is equivalent to CHECKSUM_NONE > > > > > For XDP_TX, we > > > zero the vnet header. > > Again TX offload is disabled, so packets will go out with an invalid > > checksum. > > > > > For adjusting header, XDP prog should deal with csum. > > > > > > Thanks > > That part seems right. > > > > > > > --- > > > > > The patch is needed for -stable. > > > > > --- > > > > > drivers/net/virtio_net.c | 2 +- > > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > > > > index 143d8a9..499fcc9 100644 > > > > > --- a/drivers/net/virtio_net.c > > > > > +++ b/drivers/net/virtio_net.c > > > > > @@ -413,7 +413,7 @@ static struct sk_buff *receive_small(struct net_device *dev, > > > > > void *orig_data; > > > > > u32 act; > > > > > - if (unlikely(hdr->hdr.gso_type || hdr->hdr.flags)) > > > > > + if (unlikely(hdr->hdr.gso_type)) > > > > > goto err_xdp; > > > > > xdp.data_hard_start = buf + VIRTNET_RX_PAD + vi->hdr_len; > > > > > -- > > > > > 2.7.4