From patchwork Tue Dec 10 11:33:46 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 11281929 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9550314BD for ; Tue, 10 Dec 2019 11:35:33 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 721BF20726 for ; Tue, 10 Dec 2019 11:35:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="dtYrwZZk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 721BF20726 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=amazon.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iedmn-0006B5-Rw; Tue, 10 Dec 2019 11:34:37 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iedmm-0006An-Lx for xen-devel@lists.xenproject.org; Tue, 10 Dec 2019 11:34:36 +0000 X-Inumbo-ID: 0876b100-1b41-11ea-88e7-bc764e2007e4 Received: from smtp-fw-33001.amazon.com (unknown [207.171.190.10]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 0876b100-1b41-11ea-88e7-bc764e2007e4; Tue, 10 Dec 2019 11:34:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1575977672; x=1607513672; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=SKfQoX2A8rZ0EnP2XkyIWyJjMF/So/eVFwUYzJEpgTw=; b=dtYrwZZkF/0xOh/4jeA7vHw3mTCAqC9RmbNcNXqhi1bAUHt5+ylULzw+ zGA8JghD+nq+kwj7JtoZE1ofrwryd5CxM5d2eMhVq4mvJ8lwb30LwHWy7 dq+wz+S35R2kRMGAfyhsxYxQUVdpX/PzzSqXMFybDHmKEpDY5fNGhYy+L Y=; IronPort-SDR: vewG7bUB+/omNwoB9Ygkc4A38bNyqW2e/VrOCzOaaGd4TY8FDadyuilEJ/ZdAM7WPMm0aG8e+l FNzqIDT2rUYQ== X-IronPort-AV: E=Sophos;i="5.69,299,1571702400"; d="scan'208";a="14008117" Received: from sea32-co-svc-lb4-vlan3.sea.corp.amazon.com (HELO email-inbound-relay-2a-90c42d1d.us-west-2.amazon.com) ([10.47.23.38]) by smtp-border-fw-out-33001.sea14.amazon.com with ESMTP; 10 Dec 2019 11:34:13 +0000 Received: from EX13MTAUEA001.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan3.pdx.amazon.com [10.170.41.166]) by email-inbound-relay-2a-90c42d1d.us-west-2.amazon.com (Postfix) with ESMTPS id EC26DA11A3; Tue, 10 Dec 2019 11:34:12 +0000 (UTC) Received: from EX13D32EUC001.ant.amazon.com (10.43.164.159) by EX13MTAUEA001.ant.amazon.com (10.43.61.82) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Tue, 10 Dec 2019 11:34:12 +0000 Received: from EX13MTAUEE001.ant.amazon.com (10.43.62.200) by EX13D32EUC001.ant.amazon.com (10.43.164.159) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Tue, 10 Dec 2019 11:34:11 +0000 Received: from u2f063a87eabd5f.cbg10.amazon.com (10.125.106.135) by mail-relay.amazon.com (10.43.62.226) with Microsoft SMTP Server id 15.0.1367.3 via Frontend Transport; Tue, 10 Dec 2019 11:34:09 +0000 From: Paul Durrant To: , Date: Tue, 10 Dec 2019 11:33:46 +0000 Message-ID: <20191210113347.3404-4-pdurrant@amazon.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191210113347.3404-1-pdurrant@amazon.com> References: <20191210113347.3404-1-pdurrant@amazon.com> MIME-Version: 1.0 Precedence: Bulk Subject: [Xen-devel] [PATCH v2 3/4] xen/interface: re-define FRONT/BACK_RING_ATTACH() X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Juergen Gross , Paul Durrant , Stefano Stabellini , Boris Ostrovsky Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Currently these macros are defined to re-initialize a front/back ring (respectively) to values read from the shared ring in such a way that any requests/responses that are added to the shared ring whilst the front/back is detached will be skipped over. This, in general, is not a desirable semantic since most frontend implementations will eventually block waiting for a response which would either never appear or never be processed. Since the macros are currently unused, take this opportunity to re-define them to re-initialize a front/back ring using specified values. This also allows FRONT/BACK_RING_INIT() to be re-defined in terms of FRONT/BACK_RING_ATTACH() using a specified value of 0. NOTE: BACK_RING_ATTACH() will be used directly in a subsequent patch. Signed-off-by: Paul Durrant --- Cc: Boris Ostrovsky Cc: Juergen Gross Cc: Stefano Stabellini A patch to add the FRONT/BACK_RING_ATTACH() macros to the canonical ring.h in xen.git will be sent once the definitions have been agreed. v2: - change definitions to take explicit initial index values --- include/xen/interface/io/ring.h | 29 +++++++++-------------------- 1 file changed, 9 insertions(+), 20 deletions(-) diff --git a/include/xen/interface/io/ring.h b/include/xen/interface/io/ring.h index 3f40501fc60b..2af7a1cd6658 100644 --- a/include/xen/interface/io/ring.h +++ b/include/xen/interface/io/ring.h @@ -125,35 +125,24 @@ struct __name##_back_ring { \ memset((_s)->pad, 0, sizeof((_s)->pad)); \ } while(0) -#define FRONT_RING_INIT(_r, _s, __size) do { \ - (_r)->req_prod_pvt = 0; \ - (_r)->rsp_cons = 0; \ +#define FRONT_RING_ATTACH(_r, _s, _i, __size) do { \ + (_r)->req_prod_pvt = (_i); \ + (_r)->rsp_cons = (_i); \ (_r)->nr_ents = __RING_SIZE(_s, __size); \ (_r)->sring = (_s); \ } while (0) -#define BACK_RING_INIT(_r, _s, __size) do { \ - (_r)->rsp_prod_pvt = 0; \ - (_r)->req_cons = 0; \ - (_r)->nr_ents = __RING_SIZE(_s, __size); \ - (_r)->sring = (_s); \ -} while (0) +#define FRONT_RING_INIT(_r, _s, __size) FRONT_RING_ATTACH(_r, _s, 0, __size) -/* Initialize to existing shared indexes -- for recovery */ -#define FRONT_RING_ATTACH(_r, _s, __size) do { \ - (_r)->sring = (_s); \ - (_r)->req_prod_pvt = (_s)->req_prod; \ - (_r)->rsp_cons = (_s)->rsp_prod; \ +#define BACK_RING_ATTACH(_r, _s, _i, __size) do { \ + (_r)->rsp_prod_pvt = (_i); \ + (_r)->req_cons = (_i); \ (_r)->nr_ents = __RING_SIZE(_s, __size); \ -} while (0) - -#define BACK_RING_ATTACH(_r, _s, __size) do { \ (_r)->sring = (_s); \ - (_r)->rsp_prod_pvt = (_s)->rsp_prod; \ - (_r)->req_cons = (_s)->req_prod; \ - (_r)->nr_ents = __RING_SIZE(_s, __size); \ } while (0) +#define BACK_RING_INIT(_r, _s, __size) BACK_RING_ATTACH(_r, _s, 0, __size) + /* How big is this ring? */ #define RING_SIZE(_r) \ ((_r)->nr_ents)