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=-5.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 3E1C2C5519F for ; Mon, 16 Nov 2020 13:15:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E34612223D for ; Mon, 16 Nov 2020 13:15:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="M+y2xXWi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729087AbgKPNOw (ORCPT ); Mon, 16 Nov 2020 08:14:52 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:32523 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729059AbgKPNOw (ORCPT ); Mon, 16 Nov 2020 08:14:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1605532490; 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: in-reply-to:in-reply-to:references:references; bh=aUjZhbfjFlXk2Wx2/KvJc7/sHnXVkEFdsDohxiMlro4=; b=M+y2xXWivNAzUEpj06JDwICEbCIhcO8QdHPTAGgkgzJp75zysu/BAIiThyP1f2KM62hOJ1 1oN9RGpVllrLV7rOv38FHxQervSnARjUKJRr0JqIJDBWFJfNP9I2SRlo6Fj9HTiYkc9B3K sVxbp/WWcr8/ajLHJnf4XpNlSfhZM9o= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-27-KJrPkJ4TMsC3s2EoPMOZWA-1; Mon, 16 Nov 2020 08:14:48 -0500 X-MC-Unique: KJrPkJ4TMsC3s2EoPMOZWA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AB1591009443; Mon, 16 Nov 2020 13:14:46 +0000 (UTC) Received: from [10.36.113.230] (ovpn-113-230.ams2.redhat.com [10.36.113.230]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0807150B44; Mon, 16 Nov 2020 13:14:41 +0000 (UTC) Subject: Re: [RFC, v1 0/3] msi support for platform devices To: Vikas Gupta Cc: Alex Williamson , Cornelia Huck , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Vikram Prakash , Srinath Mannam References: <20201105060257.35269-1-vikas.gupta@broadcom.com> <20201112175852.21572-1-vikas.gupta@broadcom.com> <96436cba-88e3-ddb6-36d6-000929b86979@redhat.com> From: Auger Eric Message-ID: Date: Mon, 16 Nov 2020 14:14:40 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Vikas, On 11/13/20 6:24 PM, Vikas Gupta wrote: > Hi Eric, > > On Fri, Nov 13, 2020 at 12:10 AM Auger Eric wrote: >> >> Hi Vikas, >> >> On 11/12/20 6:58 PM, Vikas Gupta wrote: >>> This RFC adds support for MSI for platform devices. >>> a) MSI(s) is/are added in addition to the normal interrupts. >>> b) The vendor specific MSI configuration can be done using >>> callbacks which is implemented as msi module. >>> c) Adds a msi handling module for the Broadcom platform devices. >>> >>> Changes from: >>> ------------- >>> v0 to v1: >>> i) Removed MSI device flag VFIO_DEVICE_FLAGS_MSI. >>> ii) Add MSI(s) at the end of the irq list of platform IRQs. >>> MSI(s) with first entry of MSI block has count and flag >>> information. >>> IRQ list: Allocation for IRQs + MSIs are allocated as below >>> Example: if there are 'n' IRQs and 'k' MSIs >>> ------------------------------------------------------- >>> |IRQ-0|IRQ-1|....|IRQ-n|MSI-0|MSI-1|MSI-2|......|MSI-k| >>> ------------------------------------------------------- >> I have not taken time yet to look at your series, but to me you should have >> |IRQ-0|IRQ-1|....|IRQ-n|MSI|MSIX >> then for setting a given MSIX (i) you would select the MSIx index and >> then set start=i count=1. > > As per your suggestion, we should have, if there are n-IRQs, k-MSIXs > and m-MSIs, allocation of IRQs should be done as below > > |IRQ0|IRQ1|......|IRQ-(n-1)|MSI|MSIX| > | | > | > |MSIX0||MSIX1||MSXI2|....|MSIX-(k-1)| > |MSI0||MSI1||MSI2|....|MSI-(m-1)| No I really meant this list of indices: IRQ0|IRQ1|......|IRQ-(n-1)|MSI|MSIX| and potentially later on IRQ0|IRQ1|......|IRQ-(n-1)|MSI|MSIX| ERR| REQ if ERR/REQ were to be added. I think the userspace could query the total number of indices using VFIO_DEVICE_GET_INFO and retrieve num_irqs (corresponding to the n wire interrupts + MSI index + MSIX index) Then userspace can loop on all the indices using VFIO_DEVICE_GET_IRQ_INFO. For each index it uses count to determine the first indices related to wire interrupts (count = 1). Then comes the MSI index, and after the MSI index. If any of those is supported, count >1, otherwise count=0. The only thing I am dubious about is can the device use a single MSI/MSIX? Because my hypothesis here is we use count to discriminate between wire first indices and other indices. > With this implementation user space can know that, at indexes n and > n+1, edge triggered interrupts are present. note wired interrupts can also be edge ones. > We may add an element in vfio_platform_irq itself to allocate MSIs/MSIXs > struct vfio_platform_irq{ > ..... > ..... > struct vfio_platform_irq *block; => this points to the block > allocation for MSIs/MSIXs and all msi/msix are type of IRQs.As wired interrupts and MSI interrupts coexist, I would store in vdev an array of wired interrupts (the existing vdev->irqs) and a new array for MSI(x) as done in the PCI code. vdev->ctx = kcalloc(nvec, sizeof(struct vfio_pci_irq_ctx), GFP_KERNEL); Does it make sense? > }; > OR > Another structure can be defined in 'vfio_pci_private.h' > struct vfio_msi_ctx { > struct eventfd_ctx *trigger; > char *name; > }; > and > struct vfio_platform_irq { > ..... > ..... > struct vfio_msi_ctx *block; => this points to the block allocation > for MSIs/MSIXs > }; > Which of the above two options sounds OK to you? Please suggest. > >> to me individual MSIs are encoded in the subindex and not in the index. >> The index just selects the "type" of interrupt. >> >> For PCI you just have: >> VFIO_PCI_INTX_IRQ_INDEX, >> VFIO_PCI_MSI_IRQ_INDEX, -> MSI index and then you play with >> start/count >> VFIO_PCI_MSIX_IRQ_INDEX, >> VFIO_PCI_ERR_IRQ_INDEX, >> VFIO_PCI_REQ_IRQ_INDEX, >> >> (include/uapi/linux/vfio.h) > > In pci case, type of interrupts is fixed so they can be 'indexed' by > these enums but for VFIO platform user space will need to iterate all > (num_irqs) indexes to know at which indexes edge triggered interrupts > are present. indeed, but can't you loop over all indices looking until count !=1? At this point you know if have finished emurating the wires. Holds if MSI(x) count !=1 of course. Thanks Eric > > Thanks, > Vikas >> >> Thanks >> >> Eric >>> MSI-0 will have count=k set and flags set accordingly. >>> >>> Vikas Gupta (3): >>> vfio/platform: add support for msi >>> vfio/platform: change cleanup order >>> vfio/platform: add Broadcom msi module >>> >>> drivers/vfio/platform/Kconfig | 1 + >>> drivers/vfio/platform/Makefile | 1 + >>> drivers/vfio/platform/msi/Kconfig | 9 + >>> drivers/vfio/platform/msi/Makefile | 2 + >>> .../vfio/platform/msi/vfio_platform_bcmplt.c | 74 ++++++ >>> drivers/vfio/platform/vfio_platform_common.c | 86 ++++++- >>> drivers/vfio/platform/vfio_platform_irq.c | 238 +++++++++++++++++- >>> drivers/vfio/platform/vfio_platform_private.h | 23 ++ >>> 8 files changed, 419 insertions(+), 15 deletions(-) >>> create mode 100644 drivers/vfio/platform/msi/Kconfig >>> create mode 100644 drivers/vfio/platform/msi/Makefile >>> create mode 100644 drivers/vfio/platform/msi/vfio_platform_bcmplt.c >>> >>