From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cmailsend09.nm.naver.com (cmailsend09.nm.naver.com [125.209.208.218]) by dpdk.org (Postfix) with ESMTP id 06697231C for ; Thu, 8 Oct 2015 06:24:46 +0200 (CEST) Received: (qmail 8237 invoked by uid 100); 8 Oct 2015 04:24:44 -0000 Received: from 10.114.49.162 (HELO cweb26.nm.nhnsystem.com) (10.114.49.162) by cmailsend09.nm.naver.com with SMTP;8 Oct 2015 04:24:44 -0000 Date: Thu, 8 Oct 2015 13:24:44 +0900 (KST) From: =?UTF-8?B?7LWc7J217ISx?= To: Bruce Richardson Message-ID: <453174c741695362e20737b147e1f@cweb26.nm.nhnsystem.com> In-Reply-To: <20151007110414.GA21348@bricha3-MOBL3> References: <47e2b06de73965fb579acd9170ae1f@cweb01.nm.nhnsystem.com> <20151007110414.GA21348@bricha3-MOBL3> MIME-Version: 1.0 Importance: normal X-Priority: 3 (Normal) X-Naver-CIP: 129.254.191.249 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: base64 X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Cc: dev@dpdk.org Subject: Re: [dpdk-dev] =?utf-8?q?Question_about_store=5Freturn=28=29_in_=7E/d?= =?utf-8?q?pdk/lib/librte=5Fdistributor/rte=5Fdistributor=2Ec?= X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list Reply-To: =?UTF-8?B?7LWc7J217ISx?= List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 08 Oct 2015 04:24:48 -0000 IERlYXIgRHIuIEJydWNlIFJpY2hhZHNvbiBhbmQgRFBESyBleHBlcnRzLgogClRoYW5rIHlvdSB2 ZXJ5IG11Y2ggZm9yIHlvdXIgcHJlY2lvdXMgYW5zd2VyIGFuZCBhZHZpY2VzLgogClRoZSBjb2Rl cyBhcmUgdmVyeSB3ZWxsIGRlc2lnbmVkLCBvcHRpbWl6ZWQsIGFuZCBwcm9ncmFtbWVkIGJ5IHZl cnkgZXhjZWxsZW50IGFyY2hpdGVjdCBhbmQgcHJvZ3JhbW1lcnMuCiAKVGhlIGRpc3RyaWJ1dG9y IGFuZCBsb2FkIGJhbGFuY2VyIGFyZSB2ZXJ5IGltcG9ydGFudCBmdW5jdGlvbnMgaW4gbmV0d29y ayBiYW5kd2lkdGggZXhwYW5zaW9uLgogCkkgZG9uJ3Qga25vdyB3aGF0IGhhcHBlbnMgaW4gbWFu eSBleGNlcHRpb25hbCBjYXNlcy4KIApJbiB0aGUgZGlzdHJpYnV0b3IgZXhhbXBsZXMsIHRoZSB3 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Y2VsbCBpbiB0aGUgcXVldWUuCiZndDsgSWYgdGhlIGxhc3QgcG9zaXRpb24gb2YgdGhlIHF1ZXVl IGlzIGFsd2F5cyBlbXB0eSwgaXQgbWF5IG5vdCBiZSBhIHByb2JsZW0uCiZndDsgIAomZ3Q7IFdv dWxkIHlvdSBjaGVjayBpdD8KJmd0OyAgCiZndDsgVGhhbmsgeW91IHZlcnkgbXVjaC4KJmd0OyAg CiZndDsgU2luY2VyZWx5IFlvdXJzLAomZ3Q7ICAKJmd0OyBJY2stU3VuZyBDaG9pLgomZ3Q7IAoK SGksCgp5ZXMsIGl0IGNhbiBvdmVyd3JpdGUgZW50cmllcyBpbiB0aGF0IGFycmF5LgoKV2hlbiBk ZXNpZ25pbmcgdGhlIGxpYnJhcnksIHRoZXJlIHdlcmUgdHdvIHBvc3NpYmxlIHVzZSBjYXNlcyB0 YWtlbiBpbnRvIGFjY291bnQ6CjEuIFRoZSB1c2VyIGRpZCBub3Qgd2FudCB0byByZXR1cm4gdGhl IHBhY2tldHMgdG8gdGhlIGRpc3RyaWJ1dG9yIGJ1dCBwYXNzIHRoZW0KZWxzZXdoZXJlIGZyb20g dGhlIHdvcmtlcnMgd2hlbiBkb25lLiBJbiB0aGlzIGNhc2UsIHRoZSBvdmVyd3JpdGluZyBkaWQg bm90IG1hdHRlci4KMi4gVGhlIHNlY29uZCBjYXNlIGlzIHdoZXJlIG9yZGVyaW5nIGlzIHRvIGJl IHByZXNlcnZlZCwgYW5kIGhlcmUgdGhlIHVzZXIgZG9lcwp3YW50IHRvIHBhc3MgdGhlbSBiYWNr IHRvIHRoZSBkaXN0cmlidXRvci4gVG8gYWNjb21vZGF0ZSB0aGlzLCB0aGUgYnVmZmVyIHNpemUK aXMgbWFkZSBjb25zaWRlcmFibHkgYmlnZ2VyIHRoYW4gdGhlIGRlZmF1bHQgYnVyc3Qgc2l6ZSwg c28gdGhhdCBhbnlvbmUgd2hvCnBvbGxzIHRoZSByaW5nIGFmdGVyIGVhY2ggYnVyc3QgKG9yIGV2 ZW4gYWZ0ZXIgZWFjaCBzZWNvbmQgYnVyc3QpIHNob3VsZCBhZ2FpbgpoYXZlIG5vIGlzc3VlcyBh bmQgYXZvaWQgcHJvYmxlbXMgd2l0aCBvdmVyd3JpdGluZyB0aGUgZW50cnkuCgpSZWdhcmRzLAov QnJ1Y2UKCg== >From yuanhan.liu@linux.intel.com Thu Oct 8 07:51:08 2015 Return-Path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by dpdk.org (Postfix) with ESMTP id 2285D68A5 for ; Thu, 8 Oct 2015 07:51:07 +0200 (CEST) Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga101.fm.intel.com with ESMTP; 07 Oct 2015 22:51:07 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.17,653,1437462000"; d="scan'208";a="787312523" Received: from yliu-dev.sh.intel.com (HELO yliu-dev) ([10.239.66.49]) by orsmga001.jf.intel.com with ESMTP; 07 Oct 2015 22:51:06 -0700 Date: Thu, 8 Oct 2015 13:54:52 +0800 From: Yuanhan Liu To: Tetsuya Mukawa Message-ID: <20151008055452.GB3115@yliu-dev.sh.intel.com> References: <1439977869-28091-1-git-send-email-mukawa@igel.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1439977869-28091-1-git-send-email-mukawa@igel.co.jp> User-Agent: Mutt/1.5.21 (2010-09-15) Cc: dev@dpdk.org Subject: Re: [dpdk-dev] [PATCH 1/3] vhost: Fix return value of GET_VRING_BASE message X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 08 Oct 2015 05:51:08 -0000 On Wed, Aug 19, 2015 at 06:51:07PM +0900, Tetsuya Mukawa wrote: > When vhost-user frontend sends GET_VRING_BASE, last used index of vring > should be returned. In DPDK vhost library, 'last_used_idx' represents it. > But the value can be over max index value. That's true, and I guess it's a design. If you look at the linux kernel vhost code, you will find that there is no such wrap, either. > To return correct value to > vhost frontend, it's needed to be masked. So, it's the frontend job to get the right value, by wrapping it within vring size. --yliu > > Signed-off-by: Tetsuya Mukawa > --- > lib/librte_vhost/virtio-net.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/lib/librte_vhost/virtio-net.c b/lib/librte_vhost/virtio-net.c > index b520ec5..144f301 100644 > --- a/lib/librte_vhost/virtio-net.c > +++ b/lib/librte_vhost/virtio-net.c > @@ -661,7 +661,8 @@ get_vring_base(struct vhost_device_ctx ctx, uint32_t index, > > state->index = index; > /* State->index refers to the queue index. The txq is 1, rxq is 0. */ > - state->num = dev->virtqueue[state->index]->last_used_idx; > + state->num = dev->virtqueue[state->index]->last_used_idx > + & (dev->virtqueue[state->index]->size - 1); > > return 0; > } > -- > 2.1.4