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=-6.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no 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 C1308C433E3 for ; Wed, 26 Aug 2020 12:14:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A10CE20838 for ; Wed, 26 Aug 2020 12:14:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="DLCrWRXa"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="d/g1akpo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729402AbgHZMOh (ORCPT ); Wed, 26 Aug 2020 08:14:37 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:57116 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729376AbgHZMBM (ORCPT ); Wed, 26 Aug 2020 08:01:12 -0400 Message-Id: <20200826112331.047917603@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1598443260; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: references:references; bh=aNA6imWCCycyDoE7I/LUogJu92HNj5sOKiAANrwrDhI=; b=DLCrWRXadgrQCf4qFjiJ+39EHne5FXGzCP9hiodZy6C8kQ1/WBZONwRpITcKeNKBrD1AWK rF/EG4OJ4JLSWL/HoTIqnPXKvoPYzGcme0j15L3eojvZ2bWAiS7Mtp6MC3bxVEb0cBOUC9 yg4BEsBD55+FiJ8p6JF3228cFuTpo4myNllLNfJ6Fh7oNyAQy3Eqj0+p/pwh4qFx+ZTFbN X8rK+gsgw02K975GfmmssF7oLxWMt/bW4zGm2/v0gmC9AwwlH59Uhn5HEaoAcw83sZ1qnk 6UwasHDKTy053t1sugGUnbd9oxc0qCPpErEWb9QDItLE7iM7JBH4ygOMbYregw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1598443260; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: references:references; bh=aNA6imWCCycyDoE7I/LUogJu92HNj5sOKiAANrwrDhI=; b=d/g1akpo73oJHiKD3AFk+oXcaGgFtQKzORD6f4yN1CPu2he0HCayOxiJxkUBpk9OkfVzCq JLPec94nQktRTKBQ== Date: Wed, 26 Aug 2020 13:16:32 +0200 From: Thomas Gleixner To: LKML Cc: x86@kernel.org, Joerg Roedel , iommu@lists.linux-foundation.org, linux-hyperv@vger.kernel.org, Haiyang Zhang , Jon Derrick , Lu Baolu , Wei Liu , "K. Y. Srinivasan" , Stephen Hemminger , Steve Wahl , Dimitri Sivanich , Russ Anderson , linux-pci@vger.kernel.org, Bjorn Helgaas , Lorenzo Pieralisi , Konrad Rzeszutek Wilk , xen-devel@lists.xenproject.org, Juergen Gross , Boris Ostrovsky , Stefano Stabellini , Marc Zyngier , Greg Kroah-Hartman , "Rafael J. Wysocki" , Megha Dey , Jason Gunthorpe , Dave Jiang , Alex Williamson , Jacob Pan , Baolu Lu , Kevin Tian , Dan Williams Subject: [patch V2 04/46] genirq/chip: Use the first chip in irq_chip_compose_msi_msg() References: <20200826111628.794979401@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-transfer-encoding: 8-bit Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org The documentation of irq_chip_compose_msi_msg() claims that with hierarchical irq domains the first chip in the hierarchy which has an irq_compose_msi_msg() callback is chosen. But the code just keeps iterating after it finds a chip with a compose callback. The x86 HPET MSI implementation relies on that behaviour, but that does not make it more correct. The message should always be composed at the domain which manages the underlying resource (e.g. APIC or remap table) because that domain knows about the required layout of the message. On X86 the following hierarchies exist: 1) vector -------- PCI/MSI 2) vector -- IR -- PCI/MSI The vector domain has a different message format than the IR (remapping) domain. So obviously the PCI/MSI domain can't compose the message without having knowledge about the parent domain, which is exactly the opposite of what hierarchical domains want to achieve. X86 actually has two different PCI/MSI chips where #1 has a compose callback and #2 does not. #2 delegates the composition to the remap domain where it belongs, but #1 does it at the PCI/MSI level. For the upcoming device MSI support it's necessary to change this and just let the first domain which can compose the message take care of it. That way the top level chip does not have to worry about it and the device MSI code does not need special knowledge about topologies. It just sets the compose callback to NULL and lets the hierarchy pick the first chip which has one. Due to that the attempt to move the compose callback from the direct delivery PCI/MSI domain to the vector domain made the system fail to boot with interrupt remapping enabled because in the remapping case irq_chip_compose_msi_msg() keeps iterating and choses the compose callback of the vector domain which obviously creates the wrong format for the remap table. Break out of the loop when the first irq chip with a compose callback is found and fixup the HPET code temporarily. That workaround will be removed once the direct delivery compose callback is moved to the place where it belongs in the vector domain. Signed-off-by: Thomas Gleixner --- V2: New patch. Note, that this might break other stuff which relies on the current behaviour, but the hierarchy composition of DT based chips is really hard to follow. --- arch/x86/kernel/apic/msi.c | 7 +++++-- kernel/irq/chip.c | 12 +++++++++--- 2 files changed, 14 insertions(+), 5 deletions(-) --- a/arch/x86/kernel/apic/msi.c +++ b/arch/x86/kernel/apic/msi.c @@ -479,10 +479,13 @@ struct irq_domain *hpet_create_irq_domai info.type = X86_IRQ_ALLOC_TYPE_HPET; info.hpet_id = hpet_id; parent = irq_remapping_get_ir_irq_domain(&info); - if (parent == NULL) + if (parent == NULL) { parent = x86_vector_domain; - else + } else { hpet_msi_controller.name = "IR-HPET-MSI"; + /* Temporary fix: Will go away */ + hpet_msi_controller.irq_compose_msi_msg = NULL; + } fn = irq_domain_alloc_named_id_fwnode(hpet_msi_controller.name, hpet_id); --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -1544,10 +1544,16 @@ int irq_chip_compose_msi_msg(struct irq_ struct irq_data *pos = NULL; #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY - for (; data; data = data->parent_data) -#endif - if (data->chip && data->chip->irq_compose_msi_msg) + for (; data; data = data->parent_data) { + if (data->chip && data->chip->irq_compose_msi_msg) { pos = data; + break; + } + } +#else + if (data->chip && data->chip->irq_compose_msi_msg) + pos = data; +#endif if (!pos) return -ENOSYS;