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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=ham 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 88666C43381 for ; Thu, 28 Feb 2019 15:09:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5537A218E0 for ; Thu, 28 Feb 2019 15:09:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551366548; bh=9re+ZwkhJKfuS+JRS4wz1OZuXPPz/Ji+yoHhD/YIw+s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=mcq2RqSot6YxoW0M+4QgJYOpsi390XS8g0DqA/b6CXCJZRnJXX0Agr16+3S6Qlyuu fJ3ZWzmY5dL5SLJDHhN6eszmcuPeNAZSbbvinokh4NmVynqR5DoAucmCixEkly7On+ P0hHOZBuAaErIRKwLexIqIZqgkVl4ufKzUmWKUTI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387451AbfB1PJH (ORCPT ); Thu, 28 Feb 2019 10:09:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:41428 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732112AbfB1PJA (ORCPT ); Thu, 28 Feb 2019 10:09:00 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E69A3218D9; Thu, 28 Feb 2019 15:08:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551366538; bh=9re+ZwkhJKfuS+JRS4wz1OZuXPPz/Ji+yoHhD/YIw+s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oREV1u9ydnI3C1D3nZykA9+QXBv+ATVKIxiRlz9aHKCToZCXcuMkZj0CHXeLGmAmP ffKmDFtVtrRlxeKYe7XBuRXC9C0fEYkm3XfX3+EbctWd06UYIiDDVtMo9tA1j7QjJe 2Z4Tw79ZxPuyWGQPIcbwe/3HyqD7fCguMxQyu1Q4= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Heyi Guo , Heyi Guo , Marc Zyngier , Sasha Levin Subject: [PATCH AUTOSEL 4.20 28/81] irqchip/gic-v4: Fix occasional VLPI drop Date: Thu, 28 Feb 2019 10:07:20 -0500 Message-Id: <20190228150813.10256-28-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190228150813.10256-1-sashal@kernel.org> References: <20190228150813.10256-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Heyi Guo [ Upstream commit 6479450f72c1391c03f08affe0d0110f41ae7ca0 ] 1. In current implementation, every VLPI will temporarily be mapped to the first CPU in system (normally CPU0) and then moved to the real scheduled CPU later. 2. So there is a time window and a VLPI may be sent to CPU0 instead of the real scheduled vCPU, in a multi-CPU virtual machine. 3. However, CPU0 may have not been scheduled as a virtual CPU after system boots up, so the value of its GICR_VPROPBASER is unknown at that moment. 4. If the INTID of VLPI is larger than 2^(GICR_VPROPBASER.IDbits+1), while IDbits is also in unknown state, GIC will behave as if the VLPI is out of range and simply drop it, which results in interrupt missing in Guest. As no code will clear GICR_VPROPBASER at runtime, we can safely initialize the IDbits field at boot time for each CPU to get rid of this issue. We also clear Valid bit of GICR_VPENDBASER in case any ancient programming gets left in and causes memory corrupting. A new function its_clear_vpend_valid() is added to reuse the code in its_vpe_deschedule(). Fixes: e643d8034036 ("irqchip/gic-v3-its: Add VPE scheduling") Signed-off-by: Heyi Guo Signed-off-by: Heyi Guo Signed-off-by: Marc Zyngier Signed-off-by: Sasha Levin --- drivers/irqchip/irq-gic-v3-its.c | 66 ++++++++++++++++++++++++-------- 1 file changed, 49 insertions(+), 17 deletions(-) diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index 350f999d205be..f25ec92f23ee2 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -2065,6 +2065,29 @@ static int __init allocate_lpi_tables(void) return 0; } +static u64 its_clear_vpend_valid(void __iomem *vlpi_base) +{ + u32 count = 1000000; /* 1s! */ + bool clean; + u64 val; + + val = gits_read_vpendbaser(vlpi_base + GICR_VPENDBASER); + val &= ~GICR_VPENDBASER_Valid; + gits_write_vpendbaser(val, vlpi_base + GICR_VPENDBASER); + + do { + val = gits_read_vpendbaser(vlpi_base + GICR_VPENDBASER); + clean = !(val & GICR_VPENDBASER_Dirty); + if (!clean) { + count--; + cpu_relax(); + udelay(1); + } + } while (!clean && count); + + return val; +} + static void its_cpu_init_lpis(void) { void __iomem *rbase = gic_data_rdist_rd_base(); @@ -2150,6 +2173,30 @@ static void its_cpu_init_lpis(void) val |= GICR_CTLR_ENABLE_LPIS; writel_relaxed(val, rbase + GICR_CTLR); + if (gic_rdists->has_vlpis) { + void __iomem *vlpi_base = gic_data_rdist_vlpi_base(); + + /* + * It's possible for CPU to receive VLPIs before it is + * sheduled as a vPE, especially for the first CPU, and the + * VLPI with INTID larger than 2^(IDbits+1) will be considered + * as out of range and dropped by GIC. + * So we initialize IDbits to known value to avoid VLPI drop. + */ + val = (LPI_NRBITS - 1) & GICR_VPROPBASER_IDBITS_MASK; + pr_debug("GICv4: CPU%d: Init IDbits to 0x%llx for GICR_VPROPBASER\n", + smp_processor_id(), val); + gits_write_vpropbaser(val, vlpi_base + GICR_VPROPBASER); + + /* + * Also clear Valid bit of GICR_VPENDBASER, in case some + * ancient programming gets left in and has possibility of + * corrupting memory. + */ + val = its_clear_vpend_valid(vlpi_base); + WARN_ON(val & GICR_VPENDBASER_Dirty); + } + /* Make sure the GIC has seen the above */ dsb(sy); out: @@ -2776,26 +2823,11 @@ static void its_vpe_schedule(struct its_vpe *vpe) static void its_vpe_deschedule(struct its_vpe *vpe) { void __iomem *vlpi_base = gic_data_rdist_vlpi_base(); - u32 count = 1000000; /* 1s! */ - bool clean; u64 val; - /* We're being scheduled out */ - val = gits_read_vpendbaser(vlpi_base + GICR_VPENDBASER); - val &= ~GICR_VPENDBASER_Valid; - gits_write_vpendbaser(val, vlpi_base + GICR_VPENDBASER); - - do { - val = gits_read_vpendbaser(vlpi_base + GICR_VPENDBASER); - clean = !(val & GICR_VPENDBASER_Dirty); - if (!clean) { - count--; - cpu_relax(); - udelay(1); - } - } while (!clean && count); + val = its_clear_vpend_valid(vlpi_base); - if (unlikely(!clean && !count)) { + if (unlikely(val & GICR_VPENDBASER_Dirty)) { pr_err_ratelimited("ITS virtual pending table not cleaning\n"); vpe->idai = false; vpe->pending_last = true; -- 2.19.1