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 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 57CE3C61D85 for ; Tue, 21 Nov 2023 14:41:23 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.637869.993911 (Exim 4.92) (envelope-from ) id 1r5Rvs-00016m-IC; Tue, 21 Nov 2023 14:40:56 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 637869.993911; Tue, 21 Nov 2023 14:40:56 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1r5Rvs-00016f-EX; Tue, 21 Nov 2023 14:40:56 +0000 Received: by outflank-mailman (input) for mailman id 637869; Tue, 21 Nov 2023 14:40:55 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1r5Rvr-00016Z-GU for xen-devel@lists.xenproject.org; Tue, 21 Nov 2023 14:40:55 +0000 Received: from mail-wm1-x334.google.com (mail-wm1-x334.google.com [2a00:1450:4864:20::334]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id f973d2ee-887b-11ee-98e1-6d05b1d4d9a1; Tue, 21 Nov 2023 15:40:54 +0100 (CET) Received: by mail-wm1-x334.google.com with SMTP id 5b1f17b1804b1-40b2c8e91afso1913425e9.3 for ; Tue, 21 Nov 2023 06:40:54 -0800 (PST) Received: from localhost ([213.195.113.99]) by smtp.gmail.com with ESMTPSA id z7-20020a05600c0a0700b003fc0505be19sm17677097wmp.37.2023.11.21.06.40.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Nov 2023 06:40:53 -0800 (PST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: f973d2ee-887b-11ee-98e1-6d05b1d4d9a1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.com; s=google; t=1700577654; x=1701182454; darn=lists.xenproject.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=5piXL3MfwdAeGGjCII4Ez9Yi2W6IULKwDiak3ZKKEu4=; b=V0CRjQxoSRPPCNTNmZtc2IsOfSKYG1uwhO371jDjb2y33Ry4bkbXPyVcGjylU+a1up PXkI15YuBsR7bn5eqLjKRm6jJxglaRz0BvbstUn2a/Ov7A8LUf7KcUI66t5JawTqwtGz 1xxlrIT56ujjxjNg9Fq/02rQjvOq9ZUzDuCzk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700577654; x=1701182454; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=5piXL3MfwdAeGGjCII4Ez9Yi2W6IULKwDiak3ZKKEu4=; b=KT83DwWHvulqvjym+OapZHxEM5alYX60P9cgNGktsrLRfU709rR2q0KypfmfTt8a8f zE7mvkA/O+pJ48FEOyeR7yUVCHEGMq/u0l21uE5FArY2J2YG90Z9yUEERea6zSSVFUW9 lUlzAn6KOYPW7U+aTPBqaiFH/aS+6b1AGl+R4wprIRQZy72Mr8XM8RNWYTrg92soNiSL KmISiLsVI8Gn2lHlKQw1KLhyhw1aH0dBNgAgw+bUTSgtiZFbGUqRF9t+kMnrjLcoYBaV 9a3NeOmCvTLBU4CcVin9HeoUn8aPZ2jOFQxvzisk8MKtMODAFATp/YNfwBAcIqcd/DZV rZSQ== X-Gm-Message-State: AOJu0YxYlwATQ92nQ8DcHUrRq+d2Rsck3JOwx29x7ICL/8z4HVYwXZX+ BVoK3W36eLrrby3k93XYnjhUKQ== X-Google-Smtp-Source: AGHT+IE8LwvDBIZTC+9I6tKRV0XGiEM2oj8HRv6ptyyipd2nwmOH/8z4xypwVIFoaVcp0bWo2l8CWA== X-Received: by 2002:a05:600c:1548:b0:405:3dbc:8823 with SMTP id f8-20020a05600c154800b004053dbc8823mr8690887wmg.12.1700577653845; Tue, 21 Nov 2023 06:40:53 -0800 (PST) Date: Tue, 21 Nov 2023 15:40:52 +0100 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Volodymyr Babchuk Cc: "xen-devel@lists.xenproject.org" , Stewart Hildebrand , Oleksandr Andrushchenko , Andrew Cooper , George Dunlap , Jan Beulich , Julien Grall , Stefano Stabellini , Wei Liu Subject: Re: [PATCH v10 13/17] vpci: add initial support for virtual PCI bus topology Message-ID: References: <20231012220854.2736994-1-volodymyr_babchuk@epam.com> <20231012220854.2736994-14-volodymyr_babchuk@epam.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20231012220854.2736994-14-volodymyr_babchuk@epam.com> On Thu, Oct 12, 2023 at 10:09:18PM +0000, Volodymyr Babchuk wrote: > From: Oleksandr Andrushchenko > > Assign SBDF to the PCI devices being passed through with bus 0. > The resulting topology is where PCIe devices reside on the bus 0 of the > root complex itself (embedded endpoints). > This implementation is limited to 32 devices which are allowed on > a single PCI bus. > > Please note, that at the moment only function 0 of a multifunction > device can be passed through. > > Signed-off-by: Oleksandr Andrushchenko > --- > In v10: > - Removed ASSERT(pcidevs_locked()) > - Removed redundant code (local sbdf variable, clearing sbdf during > device removal, etc) > - Added __maybe_unused attribute to "out:" label > - Introduced HAS_VPCI_GUEST_SUPPORT Kconfig option, as this is the > first patch where it is used (previously was in "vpci: add hooks for > PCI device assign/de-assign") > In v9: > - Lock in add_virtual_device() replaced with ASSERT (thanks, Stewart) > In v8: > - Added write lock in add_virtual_device > Since v6: > - re-work wrt new locking scheme > - OT: add ASSERT(pcidevs_write_locked()); to add_virtual_device() > Since v5: > - s/vpci_add_virtual_device/add_virtual_device and make it static > - call add_virtual_device from vpci_assign_device and do not use > REGISTER_VPCI_INIT machinery > - add pcidevs_locked ASSERT > - use DECLARE_BITMAP for vpci_dev_assigned_map > Since v4: > - moved and re-worked guest sbdf initializers > - s/set_bit/__set_bit > - s/clear_bit/__clear_bit > - minor comment fix s/Virtual/Guest/ > - added VPCI_MAX_VIRT_DEV constant (PCI_SLOT(~0) + 1) which will be used > later for counting the number of MMIO handlers required for a guest > (Julien) > Since v3: > - make use of VPCI_INIT > - moved all new code to vpci.c which belongs to it > - changed open-coded 31 to PCI_SLOT(~0) > - added comments and code to reject multifunction devices with > functions other than 0 > - updated comment about vpci_dev_next and made it unsigned int > - implement roll back in case of error while assigning/deassigning devices > - s/dom%pd/%pd > Since v2: > - remove casts that are (a) malformed and (b) unnecessary > - add new line for better readability > - remove CONFIG_HAS_VPCI_GUEST_SUPPORT ifdef's as the relevant vPCI > functions are now completely gated with this config > - gate common code with CONFIG_HAS_VPCI_GUEST_SUPPORT > New in v2 > --- > xen/drivers/Kconfig | 4 +++ > xen/drivers/vpci/vpci.c | 63 +++++++++++++++++++++++++++++++++++++++++ > xen/include/xen/sched.h | 8 ++++++ > xen/include/xen/vpci.h | 11 +++++++ > 4 files changed, 86 insertions(+) > > diff --git a/xen/drivers/Kconfig b/xen/drivers/Kconfig > index db94393f47..780490cf8e 100644 > --- a/xen/drivers/Kconfig > +++ b/xen/drivers/Kconfig > @@ -15,4 +15,8 @@ source "drivers/video/Kconfig" > config HAS_VPCI > bool > > +config HAS_VPCI_GUEST_SUPPORT > + bool > + depends on HAS_VPCI > + > endmenu > diff --git a/xen/drivers/vpci/vpci.c b/xen/drivers/vpci/vpci.c > index 5e34d0092a..7c46a2d3f4 100644 > --- a/xen/drivers/vpci/vpci.c > +++ b/xen/drivers/vpci/vpci.c > @@ -36,6 +36,52 @@ extern vpci_register_init_t *const __start_vpci_array[]; > extern vpci_register_init_t *const __end_vpci_array[]; > #define NUM_VPCI_INIT (__end_vpci_array - __start_vpci_array) > > +#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT > +static int add_virtual_device(struct pci_dev *pdev) > +{ > + struct domain *d = pdev->domain; > + unsigned long new_dev_number; Why unsigned long? unsigned int seems more than enough to account for all possible dev numbers [0, 31]. > + > + if ( is_hardware_domain(d) ) > + return 0; > + > + ASSERT(rw_is_write_locked(&pdev->domain->pci_lock)); > + > + /* > + * Each PCI bus supports 32 devices/slots at max or up to 256 when > + * there are multi-function ones which are not yet supported. > + */ > + if ( pdev->info.is_extfn && !pdev->info.is_virtfn ) > + { > + gdprintk(XENLOG_ERR, "%pp: only function 0 passthrough supported\n", > + &pdev->sbdf); > + return -EOPNOTSUPP; > + } > + new_dev_number = find_first_zero_bit(d->vpci_dev_assigned_map, > + VPCI_MAX_VIRT_DEV); > + if ( new_dev_number == VPCI_MAX_VIRT_DEV ) > + { > + write_unlock(&pdev->domain->pci_lock); This write_unlock() looks bogus, as the lock is not taken by this function. Won't this create an unlock imbalance when the caller of vpci_assign_device() also attempts to write-unlock d->pci_lock? > + return -ENOSPC; > + } > + > + __set_bit(new_dev_number, &d->vpci_dev_assigned_map); > + > + /* > + * Both segment and bus number are 0: > + * - we emulate a single host bridge for the guest, e.g. segment 0 > + * - with bus 0 the virtual devices are seen as embedded > + * endpoints behind the root complex > + * > + * TODO: add support for multi-function devices. > + */ > + pdev->vpci->guest_sbdf = PCI_SBDF(0, 0, new_dev_number, 0); > + > + return 0; > +} > + > +#endif /* CONFIG_HAS_VPCI_GUEST_SUPPORT */ > + > void vpci_deassign_device(struct pci_dev *pdev) > { > unsigned int i; > @@ -46,6 +92,13 @@ void vpci_deassign_device(struct pci_dev *pdev) > return; > > spin_lock(&pdev->vpci->lock); > + > +#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT > + if ( pdev->vpci->guest_sbdf.sbdf != ~0 ) > + __clear_bit(pdev->vpci->guest_sbdf.dev, > + &pdev->domain->vpci_dev_assigned_map); > +#endif This chunk could in principle be outside of the vpci->lock region AFAICT. > + > while ( !list_empty(&pdev->vpci->handlers) ) > { > struct vpci_register *r = list_first_entry(&pdev->vpci->handlers, > @@ -101,6 +154,13 @@ int vpci_assign_device(struct pci_dev *pdev) > INIT_LIST_HEAD(&pdev->vpci->handlers); > spin_lock_init(&pdev->vpci->lock); > > +#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT > + pdev->vpci->guest_sbdf.sbdf = ~0; > + rc = add_virtual_device(pdev); > + if ( rc ) > + goto out; > +#endif > + > for ( i = 0; i < NUM_VPCI_INIT; i++ ) > { > rc = __start_vpci_array[i](pdev); > @@ -108,11 +168,14 @@ int vpci_assign_device(struct pci_dev *pdev) > break; > } > > + out: > + __maybe_unused; Can you place it in the same line as the out: label please? > if ( rc ) > vpci_deassign_device(pdev); > > return rc; > } > + Stray newline? Thanks, Roger.