From patchwork Mon Feb 19 18:58:06 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Upton X-Patchwork-Id: 13562986 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C62A2C48BC3 for ; Mon, 19 Feb 2024 18:58:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=E2QTMhLDeDoBz5CZqsJCdDpXmJu5+ZMt/KgRdi19Z+0=; b=wLmtGryQQRNu+5 eqVsmTYUdDQI/756by38V0rDutH6UQTuqKqJyVOCO834SMRdnLzLZAkuYFusuv+RDhOpI/kuL+Sey aCaFij+WqV1N85kPoCEaJaO/UL8B9VYLOlEBz9yFohl/XVdh9o2my9VSmXJkRrqpBeR4LqJc7MzAB /nOV8IiMv8eTOTwk4DuD/7lwbqxO2pNunkUFnHKLuzuKBGL6bzJ2gafMwxSLam12OzY3Gx0TrFkxm iKM+Lw6A/YN1WaBM7zBR0ISPv17fDY4TTt0+gJ+gLkLvMgrmkxdeFyYe7Y8TjDTIXChKQ+yClwWgY 30u+d4o9oTLAj1HG2H3w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rc8qc-0000000BoEf-3Urr; Mon, 19 Feb 2024 18:58:38 +0000 Received: from out-170.mta0.migadu.com ([2001:41d0:1004:224b::aa]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rc8qQ-0000000Bo6P-1xNa for linux-arm-kernel@lists.infradead.org; Mon, 19 Feb 2024 18:58:27 +0000 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1708369103; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=malznfxmTFeYI5AQuBOcx//3J2Klq63IEw4UgO+FW8I=; b=TymjM0U4219Zm3uEd/Lb8NxsD72R3xzRJZRLZBjvd9XHgLBu8YMPWhynBzrl8JRv3paxch lwj9pWCJOssGT/aTbkmYfA4DY/0hoWqJyMUQMa+NXEZkMY7B5s52UXj0Q2QgC1umO8It4y kkbdXBlbN4LMCE9vFrfXl6eQVykFEc8= From: Oliver Upton To: Thomas Gleixner Cc: Marc Zyngier , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, Jing Zhang , Oliver Upton , stable@vger.kernel.org, George Cherian Subject: [PATCH 1/3] irqchip/gic-v3-its: Do not assume vPE tables are preallocated Date: Mon, 19 Feb 2024 18:58:06 +0000 Message-ID: <20240219185809.286724-2-oliver.upton@linux.dev> In-Reply-To: <20240219185809.286724-1-oliver.upton@linux.dev> References: <20240219185809.286724-1-oliver.upton@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240219_105826_678664_95AC988E X-CRM114-Status: GOOD ( 13.87 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org We go through quite a bit of trouble to make sure we pick up any preallocated LPI tables on the redistributors, as enabling LPIs is a one-way switch. There is no such restriction for vLPIs, and for GICv4.1 we expect to allocate a new vPE table at boot. This works as intended when initializing an ITS, however when setting up a redistributor in its_cpu_init_lpis() the early return for preallocated RD tables skips straight past GICv4 setup. This all comes to a head when trying to kexec into a new kernel, as the new kernel silently fails to set up GICv4, leading to a complete loss of SGIs and LPIs for KVM VMs (ouch). Slap a band-aid on the problem by ensuring its_cpu_init_lpis() always initializes GICv4 on the way out, even if the other RD tables were preallocated. Cc: stable@vger.kernel.org Fixes: 6479450f72c1 ("irqchip/gic-v4: Fix occasional VLPI drop") Reported-by: George Cherian Co-developed-by: Marc Zyngier Signed-off-by: Marc Zyngier Signed-off-by: Oliver Upton --- I debated a bit on the fixes tag between the blamed commit and commit 5e5168461c22 ("irqchip/gic-v4.1: VPE table (aka GICR_VPROPBASER) allocation"), although it would appear GICv4 could be left in an unknown state after kexec too. drivers/irqchip/irq-gic-v3-its.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index d097001c1e3e..0022852ce494 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -3172,6 +3172,7 @@ static void its_cpu_init_lpis(void) val |= GICR_CTLR_ENABLE_LPIS; writel_relaxed(val, rbase + GICR_CTLR); +out: if (gic_rdists->has_vlpis && !gic_rdists->has_rvpeid) { void __iomem *vlpi_base = gic_data_rdist_vlpi_base(); @@ -3207,7 +3208,6 @@ static void its_cpu_init_lpis(void) /* Make sure the GIC has seen the above */ dsb(sy); -out: gic_data_rdist()->flags |= RD_LOCAL_LPI_ENABLED; pr_info("GICv3: CPU%d: using %s LPI pending table @%pa\n", smp_processor_id(),