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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A4A02C433EF for ; Tue, 12 Oct 2021 16:17:44 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2A4B260238 for ; Tue, 12 Oct 2021 16:17:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 2A4B260238 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:42262 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1maKTH-0002vG-6d for qemu-devel@archiver.kernel.org; Tue, 12 Oct 2021 12:17:43 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60486) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1maKQ5-0008Qi-Ay; Tue, 12 Oct 2021 12:14:25 -0400 Received: from mga11.intel.com ([192.55.52.93]:30355) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1maKQ2-0001k8-VS; Tue, 12 Oct 2021 12:14:25 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10135"; a="224622389" X-IronPort-AV: E=Sophos;i="5.85,368,1624345200"; d="scan'208";a="224622389" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Oct 2021 09:07:58 -0700 X-IronPort-AV: E=Sophos;i="5.85,368,1624345200"; d="scan'208";a="491039772" Received: from lmaniak-dev.igk.intel.com ([10.55.248.48]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Oct 2021 09:07:52 -0700 Date: Tue, 12 Oct 2021 18:06:46 +0200 From: Lukasz Maniak To: "Michael S. Tsirkin" Subject: Re: [PATCH 04/15] pcie: Add callback preceding SR-IOV VFs update Message-ID: <20211012160646.GA2286339@lmaniak-dev.igk.intel.com> References: <20211007162406.1920374-1-lukasz.maniak@linux.intel.com> <20211007162406.1920374-5-lukasz.maniak@linux.intel.com> <20211012032026-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211012032026-mutt-send-email-mst@kernel.org> Received-SPF: none client-ip=192.55.52.93; envelope-from=lukasz.maniak@linux.intel.com; helo=mga11.intel.com X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: =?utf-8?Q?=C5=81ukasz?= Gieryk , Knut Omang , qemu-devel@nongnu.org, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Oct 12, 2021 at 03:25:12AM -0400, Michael S. Tsirkin wrote: > On Thu, Oct 07, 2021 at 06:23:55PM +0200, Lukasz Maniak wrote: > > PCIe devices implementing SR-IOV may need to perform certain actions > > before the VFs are unrealized or vice versa. > > > > Signed-off-by: Lukasz Maniak > > Callbacks are annoying and easy to misuse though. > VFs are enabled through a config cycle, we generally just > have devices invoke the capability handler. > E.g. > > static void pci_bridge_dev_write_config(PCIDevice *d, > uint32_t address, uint32_t val, int len) > { > pci_bridge_write_config(d, address, val, len); > if (msi_present(d)) { > msi_write_config(d, address, val, len); > } > } > > this makes it easy to do whatever you want before/after > the write. You can also add a helper to check > that SRIOV is being enabled/disabled if necessary. > > > --- > > docs/pcie_sriov.txt | 2 +- > > hw/pci/pcie_sriov.c | 14 +++++++++++++- > > include/hw/pci/pcie_sriov.h | 8 +++++++- > > 3 files changed, 21 insertions(+), 3 deletions(-) > > > > diff --git a/docs/pcie_sriov.txt b/docs/pcie_sriov.txt > > index f5e891e1d4..63ca1a7b8e 100644 > > --- a/docs/pcie_sriov.txt > > +++ b/docs/pcie_sriov.txt > > @@ -57,7 +57,7 @@ setting up a BAR for a VF. > > /* Add and initialize the SR/IOV capability */ > > pcie_sriov_pf_init(d, 0x200, "your_virtual_dev", > > vf_devid, initial_vfs, total_vfs, > > - fun_offset, stride); > > + fun_offset, stride, pre_vfs_update_cb); > > > > /* Set up individual VF BARs (parameters as for normal BARs) */ > > pcie_sriov_pf_init_vf_bar( ... ) > > diff --git a/hw/pci/pcie_sriov.c b/hw/pci/pcie_sriov.c > > index 501a1ff433..cac2aee061 100644 > > --- a/hw/pci/pcie_sriov.c > > +++ b/hw/pci/pcie_sriov.c > > @@ -30,7 +30,8 @@ static void unregister_vfs(PCIDevice *dev); > > void pcie_sriov_pf_init(PCIDevice *dev, uint16_t offset, > > const char *vfname, uint16_t vf_dev_id, > > uint16_t init_vfs, uint16_t total_vfs, > > - uint16_t vf_offset, uint16_t vf_stride) > > + uint16_t vf_offset, uint16_t vf_stride, > > + SriovVfsUpdate pre_vfs_update) > > { > > uint8_t *cfg = dev->config + offset; > > uint8_t *wmask; > > @@ -41,6 +42,7 @@ void pcie_sriov_pf_init(PCIDevice *dev, uint16_t offset, > > dev->exp.sriov_pf.num_vfs = 0; > > dev->exp.sriov_pf.vfname = g_strdup(vfname); > > dev->exp.sriov_pf.vf = NULL; > > + dev->exp.sriov_pf.pre_vfs_update = pre_vfs_update; > > > > pci_set_word(cfg + PCI_SRIOV_VF_OFFSET, vf_offset); > > pci_set_word(cfg + PCI_SRIOV_VF_STRIDE, vf_stride); > > @@ -180,6 +182,11 @@ static void register_vfs(PCIDevice *dev) > > assert(dev->exp.sriov_pf.vf); > > > > trace_sriov_register_vfs(SRIOV_ID(dev), num_vfs); > > + > > + if (dev->exp.sriov_pf.pre_vfs_update) { > > + dev->exp.sriov_pf.pre_vfs_update(dev, dev->exp.sriov_pf.num_vfs, num_vfs); > > + } > > + > > for (i = 0; i < num_vfs; i++) { > > dev->exp.sriov_pf.vf[i] = register_vf(dev, devfn, dev->exp.sriov_pf.vfname, i); > > if (!dev->exp.sriov_pf.vf[i]) { > > @@ -198,6 +205,11 @@ static void unregister_vfs(PCIDevice *dev) > > uint16_t i; > > > > trace_sriov_unregister_vfs(SRIOV_ID(dev), num_vfs); > > + > > + if (dev->exp.sriov_pf.pre_vfs_update) { > > + dev->exp.sriov_pf.pre_vfs_update(dev, dev->exp.sriov_pf.num_vfs, 0); > > + } > > + > > for (i = 0; i < num_vfs; i++) { > > PCIDevice *vf = dev->exp.sriov_pf.vf[i]; > > object_property_set_bool(OBJECT(vf), "realized", false, &local_err); > > diff --git a/include/hw/pci/pcie_sriov.h b/include/hw/pci/pcie_sriov.h > > index 0974f00054..9ab48b79c0 100644 > > --- a/include/hw/pci/pcie_sriov.h > > +++ b/include/hw/pci/pcie_sriov.h > > @@ -13,11 +13,16 @@ > > #ifndef QEMU_PCIE_SRIOV_H > > #define QEMU_PCIE_SRIOV_H > > > > +typedef void (*SriovVfsUpdate)(PCIDevice *dev, uint16_t prev_num_vfs, > > + uint16_t num_vfs); > > + > > struct PCIESriovPF { > > uint16_t num_vfs; /* Number of virtual functions created */ > > uint8_t vf_bar_type[PCI_NUM_REGIONS]; /* Store type for each VF bar */ > > const char *vfname; /* Reference to the device type used for the VFs */ > > PCIDevice **vf; /* Pointer to an array of num_vfs VF devices */ > > + > > + SriovVfsUpdate pre_vfs_update; /* Callback preceding VFs count change */ > > }; > > > > struct PCIESriovVF { > > @@ -28,7 +33,8 @@ struct PCIESriovVF { > > void pcie_sriov_pf_init(PCIDevice *dev, uint16_t offset, > > const char *vfname, uint16_t vf_dev_id, > > uint16_t init_vfs, uint16_t total_vfs, > > - uint16_t vf_offset, uint16_t vf_stride); > > + uint16_t vf_offset, uint16_t vf_stride, > > + SriovVfsUpdate pre_vfs_update); > > void pcie_sriov_pf_exit(PCIDevice *dev); > > > > /* Set up a VF bar in the SR/IOV bar area */ > > -- > > 2.25.1 > Hi Michael, A custom config_write callback was the first approach we used. However, once implemented, we realized it looks the same as the pcie_sriov_config_write function. To avoid code duplication and interfering with the internal SR-IOV structures for purposes of NVMe, we opted for this callback prior to the VFs update. After all, we have callbacks in both approaches, config_write and the added pre_vfs_update, so both are prone to misuse. But I agree it may not be a good moment yet to add a new API specifically for SR-IOV functionality, as NVMe will be the first device to use it. CCing Knut, perhaps as the author of SR-IOV you have some thoughts on how the device notification of an upcoming VFs update would be handled. Thanks, Lukasz