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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 15E57C43460 for ; Mon, 17 May 2021 14:11:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EEE986143B for ; Mon, 17 May 2021 14:11:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238083AbhEQOMS (ORCPT ); Mon, 17 May 2021 10:12:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:60494 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238380AbhEQOKO (ORCPT ); Mon, 17 May 2021 10:10:14 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8606B613B9; Mon, 17 May 2021 14:07:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621260438; bh=/SQeMdUInnr8U4spjHYXZiZDvRqcnWFmA2sRHywOT+c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MA+4h0b8LK/jFzrev4ElMw95xoj2dPTTgw4g8YgvTzYOfuvZRDXzSse4GcE6TZRMR 60Uz2jTn5U7qzb/rUr74Sr5hADwuaw8B/h21s0K7+ThlHbCPifSkb8WIhxb9QjAsE7 K2mkB3n7Z5fKSXxfcAu7vt9xmELwJYpdv5SIPogk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Tj (Elloe Linux)" , Shuah Khan , Alexander Monakov , David Coe , Paul Menzel , Suravee Suthikulpanit , Joerg Roedel , Sasha Levin Subject: [PATCH 5.12 082/363] Revert "iommu/amd: Fix performance counter initialization" Date: Mon, 17 May 2021 15:59:08 +0200 Message-Id: <20210517140305.374038205@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210517140302.508966430@linuxfoundation.org> References: <20210517140302.508966430@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Paul Menzel [ Upstream commit 715601e4e36903a653cd4294dfd3ed0019101991 ] This reverts commit 6778ff5b21bd8e78c8bd547fd66437cf2657fd9b. The original commit tries to address an issue, where PMC power-gating causing the IOMMU PMC pre-init test to fail on certain desktop/mobile platforms where the power-gating is normally enabled. There have been several reports that the workaround still does not guarantee to work, and can add up to 100 ms (on the worst case) to the boot process on certain platforms such as the MSI B350M MORTAR with AMD Ryzen 3 2200G. Therefore, revert this commit as a prelude to removing the pre-init test. Link: https://lore.kernel.org/linux-iommu/alpine.LNX.3.20.13.2006030935570.3181@monopod.intra.ispras.ru/ Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201753 Cc: Tj (Elloe Linux) Cc: Shuah Khan Cc: Alexander Monakov Cc: David Coe Signed-off-by: Paul Menzel Signed-off-by: Suravee Suthikulpanit Link: https://lore.kernel.org/r/20210409085848.3908-2-suravee.suthikulpanit@amd.com Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin --- drivers/iommu/amd/init.c | 45 ++++++++++------------------------------ 1 file changed, 11 insertions(+), 34 deletions(-) diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c index f7e31018cd0b..ad53f516e46e 100644 --- a/drivers/iommu/amd/init.c +++ b/drivers/iommu/amd/init.c @@ -12,7 +12,6 @@ #include #include #include -#include #include #include #include @@ -257,8 +256,6 @@ static enum iommu_init_state init_state = IOMMU_START_STATE; static int amd_iommu_enable_interrupts(void); static int __init iommu_go_to_state(enum iommu_init_state state); static void init_device_table_dma(void); -static int iommu_pc_get_set_reg(struct amd_iommu *iommu, u8 bank, u8 cntr, - u8 fxn, u64 *value, bool is_write); static bool amd_iommu_pre_enabled = true; @@ -1717,11 +1714,13 @@ static int __init init_iommu_all(struct acpi_table_header *table) return 0; } -static void __init init_iommu_perf_ctr(struct amd_iommu *iommu) +static int iommu_pc_get_set_reg(struct amd_iommu *iommu, u8 bank, u8 cntr, + u8 fxn, u64 *value, bool is_write); + +static void init_iommu_perf_ctr(struct amd_iommu *iommu) { - int retry; struct pci_dev *pdev = iommu->dev; - u64 val = 0xabcd, val2 = 0, save_reg, save_src; + u64 val = 0xabcd, val2 = 0, save_reg = 0; if (!iommu_feature(iommu, FEATURE_PC)) return; @@ -1729,39 +1728,17 @@ static void __init init_iommu_perf_ctr(struct amd_iommu *iommu) amd_iommu_pc_present = true; /* save the value to restore, if writable */ - if (iommu_pc_get_set_reg(iommu, 0, 0, 0, &save_reg, false) || - iommu_pc_get_set_reg(iommu, 0, 0, 8, &save_src, false)) - goto pc_false; - - /* - * Disable power gating by programing the performance counter - * source to 20 (i.e. counts the reads and writes from/to IOMMU - * Reserved Register [MMIO Offset 1FF8h] that are ignored.), - * which never get incremented during this init phase. - * (Note: The event is also deprecated.) - */ - val = 20; - if (iommu_pc_get_set_reg(iommu, 0, 0, 8, &val, true)) + if (iommu_pc_get_set_reg(iommu, 0, 0, 0, &save_reg, false)) goto pc_false; /* Check if the performance counters can be written to */ - val = 0xabcd; - for (retry = 5; retry; retry--) { - if (iommu_pc_get_set_reg(iommu, 0, 0, 0, &val, true) || - iommu_pc_get_set_reg(iommu, 0, 0, 0, &val2, false) || - val2) - break; - - /* Wait about 20 msec for power gating to disable and retry. */ - msleep(20); - } - - /* restore */ - if (iommu_pc_get_set_reg(iommu, 0, 0, 0, &save_reg, true) || - iommu_pc_get_set_reg(iommu, 0, 0, 8, &save_src, true)) + if ((iommu_pc_get_set_reg(iommu, 0, 0, 0, &val, true)) || + (iommu_pc_get_set_reg(iommu, 0, 0, 0, &val2, false)) || + (val != val2)) goto pc_false; - if (val != val2) + /* restore */ + if (iommu_pc_get_set_reg(iommu, 0, 0, 0, &save_reg, true)) goto pc_false; pci_info(pdev, "IOMMU performance counters supported\n"); -- 2.30.2