From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 890FAC49EA6 for ; Sat, 26 Jun 2021 11:02:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6C6696145E for ; Sat, 26 Jun 2021 11:02:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230177AbhFZLE7 (ORCPT ); Sat, 26 Jun 2021 07:04:59 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:8442 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229970AbhFZLEg (ORCPT ); Sat, 26 Jun 2021 07:04:36 -0400 Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4GBrTm6X88zZkCw; Sat, 26 Jun 2021 18:59:08 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Sat, 26 Jun 2021 19:02:12 +0800 Received: from thunder-town.china.huawei.com (10.174.179.0) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Sat, 26 Jun 2021 19:02:11 +0800 From: Zhen Lei To: Will Deacon , Robin Murphy , "Joerg Roedel" , linux-arm-kernel , iommu , linux-kernel CC: Zhen Lei Subject: [PATCH RFC 7/8] iommu/arm-smmu-v3: Add arm_smmu_ecmdq_issue_cmdlist() for non-shared ECMDQ Date: Sat, 26 Jun 2021 19:01:29 +0800 Message-ID: <20210626110130.2416-8-thunder.leizhen@huawei.com> X-Mailer: git-send-email 2.26.0.windows.1 In-Reply-To: <20210626110130.2416-1-thunder.leizhen@huawei.com> References: <20210626110130.2416-1-thunder.leizhen@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.174.179.0] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When a core can exclusively own an ECMDQ, competition with other cores does not need to be considered during command insertion. Therefore, we can delete the part of arm_smmu_cmdq_issue_cmdlist() that deals with multi-core contention and generate a more efficient ECMDQ-specific function arm_smmu_ecmdq_issue_cmdlist(). Signed-off-by: Zhen Lei --- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 85 +++++++++++++++++++++ drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 1 + 2 files changed, 86 insertions(+) diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c index d5205030710bd1a..a088f2479fc6223 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -769,6 +769,87 @@ static void arm_smmu_cmdq_write_entries(struct arm_smmu_cmdq *cmdq, u64 *cmds, } } +/* + * The function is used when the current core exclusively occupies an ECMDQ. + * This is a reduced version of arm_smmu_cmdq_issue_cmdlist(), which eliminates + * a lot of unnecessary inter-core competition considerations. + */ +static int arm_smmu_ecmdq_issue_cmdlist(struct arm_smmu_device *smmu, + struct arm_smmu_cmdq *cmdq, + u64 *cmds, int n, bool sync) +{ + u32 prod; + unsigned long flags; + struct arm_smmu_ll_queue llq = { + .max_n_shift = cmdq->q.llq.max_n_shift, + }, head; + int ret = 0; + + /* 1. Allocate some space in the queue */ + local_irq_save(flags); + llq.val = READ_ONCE(cmdq->q.llq.val); + do { + u64 old; + + while (!queue_has_space(&llq, n + sync)) { + local_irq_restore(flags); + if (arm_smmu_cmdq_poll_until_not_full(smmu, &llq)) + dev_err_ratelimited(smmu->dev, "ECMDQ timeout\n"); + local_irq_save(flags); + } + + head.cons = llq.cons; + head.prod = queue_inc_prod_n(&llq, n + sync); + + old = cmpxchg_relaxed(&cmdq->q.llq.val, llq.val, head.val); + if (old == llq.val) + break; + + llq.val = old; + } while (1); + + /* 2. Write our commands into the queue */ + arm_smmu_cmdq_write_entries(cmdq, cmds, llq.prod, n); + if (sync) { + u64 cmd_sync[CMDQ_ENT_DWORDS]; + + prod = queue_inc_prod_n(&llq, n); + arm_smmu_cmdq_build_sync_cmd(cmd_sync, smmu, &cmdq->q, prod); + queue_write(Q_ENT(&cmdq->q, prod), cmd_sync, CMDQ_ENT_DWORDS); + } + + /* 3. Ensuring commands are visible first */ + dma_wmb(); + + /* 4. Advance the hardware prod pointer */ + read_lock(&cmdq->q.ecmdq_lock); + writel_relaxed(head.prod | cmdq->q.ecmdq_prod, cmdq->q.prod_reg); + read_unlock(&cmdq->q.ecmdq_lock); + + /* 5. If we are inserting a CMD_SYNC, we must wait for it to complete */ + if (sync) { + llq.prod = queue_inc_prod_n(&llq, n); + ret = arm_smmu_cmdq_poll_until_sync(smmu, &llq); + if (ret) { + dev_err_ratelimited(smmu->dev, + "CMD_SYNC timeout at 0x%08x [hwprod 0x%08x, hwcons 0x%08x]\n", + llq.prod, + readl_relaxed(cmdq->q.prod_reg), + readl_relaxed(cmdq->q.cons_reg)); + } + + /* + * Update cmdq->q.llq.cons, to improve the success rate of + * queue_has_space() when some new commands are inserted next + * time. + */ + WRITE_ONCE(cmdq->q.llq.cons, llq.cons); + } + + local_irq_restore(flags); + return ret; +} + /* * This is the actual insertion function, and provides the following * ordering guarantees to callers: @@ -798,6 +879,9 @@ static int arm_smmu_cmdq_issue_cmdlist(struct arm_smmu_device *smmu, }, head = llq; int ret = 0; + if (!cmdq->shared) + return arm_smmu_ecmdq_issue_cmdlist(smmu, cmdq, cmds, n, sync); + /* 1. Allocate some space in the queue */ local_irq_save(flags); llq.val = READ_ONCE(cmdq->q.llq.val); @@ -3001,6 +3085,7 @@ static int arm_smmu_cmdq_init(struct arm_smmu_device *smmu) unsigned int nents = 1 << cmdq->q.llq.max_n_shift; atomic_long_t *bitmap; + cmdq->shared = 1; atomic_set(&cmdq->owner_prod, 0); atomic_set(&cmdq->lock, 0); diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h index 3f3a867a4626fcd..c6efbea3c0a1cda 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h @@ -569,6 +569,7 @@ struct arm_smmu_cmdq { atomic_long_t *valid_map; atomic_t owner_prod; atomic_t lock; + int shared; }; struct arm_smmu_ecmdq { -- 2.26.0.106.g9fadedd