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Wed, 27 Mar 2019 20:13:19 +0300 (MSK) Received: from [172.17.15.60] (172.17.15.60) by T-EXCH-02.corp.yadro.com (172.17.10.102) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384) id 15.1.669.32; Wed, 27 Mar 2019 20:13:18 +0300 Subject: Re: [PATCH RFC v4 03/21] PCI: Enable bridge's I/O and MEM access for hotplugged devices To: Bjorn Helgaas CC: , , References: <20190311133122.11417-1-s.miroshnichenko@yadro.com> <20190311133122.11417-4-s.miroshnichenko@yadro.com> <20190326191307.GM24180@google.com> From: Sergey Miroshnichenko Openpgp: preference=signencrypt Autocrypt: addr=s.miroshnichenko@yadro.com; prefer-encrypt=mutual; keydata= xsFNBFm31LoBEAC1wCndw8xXjGaJOinDBeVD1/8TFlVehvafur6V9xH3gsHhs0weDcMgw2Ki r5ZVhS8BlltU0snpsnQHxYB5BF0gzCLwwPUjFPZ7E0/++ylbNJoGe53cVbE870NK5WqoSEUg QtTQev2/Y5q0v7kfMh9g5p5jzeqfQSZzOrEP4d1cg5tPNKYji5cCfB/NQTHWV9w4EPj3UJQT ZPp4xqMAXu0JU1W9/XecNobKaHfEv9T+UWdx2eufiNqCgfAkRVCl8V0tKhQ4PZlZdp0dQH/N BreUg1+QJ4/t2SyEsiIPqYxFBW6qWAgOP5fzGNG31VHaQeJCA31keh84/8t632HZ4FDRrS3N 6V7Oc0ew7h5AwgOca4d3TTn8ATfASQ5vAxHC2ZK9CZhfa3RgK+8X5+vwkqc8O70iTmE9Goap uDMtgvIc0r0PHTiB3eZlyHExMD+FIOBOp2GvL7BmFHMgyOjNDdh2vBNqUwiv1RTQVWPhNX/J 4ZhTAZuAr5+6S/iRFpWspCqKvgonPxSzfWRS5dWJ2kavuvXkSB5eyPx9XRgrWxZwVdseuTpi CeTEW9/noDDl1edZdWHGWS9/4BC1nByitYYUcPXuzSkIsuae2tDw+lnsQfgAn+pXT6ESjEnZ LGnnWMQNLISf8yIaEh6bft+vXT67o1G2/U6VN1+suUPcDgYEVQARAQABzTJTZXJnZWkgTWly b3NobmljaGVua28gPHMubWlyb3NobmljaGVua29AeWFkcm8uY29tPsLBlAQTAQgAPhYhBB1u 0+6Lz/3BafPm9wx0PmjRU7O1BQJZt9S6AhsjBQkJZgGABQsJCAcCBhUICQoLAgQWAgMBAh4B AheAAAoJEAx0PmjRU7O1WfEP/jdWabDp11EdD9ZCK8LlwZ/SgXVfr9lZ5Kx3VVI68KAcfupH 3m+1lGTOktpRu7gQaj867KCbzRCWJjoVibrBgMMaFZQX2Bf2usxuBN9QxUnehg3R5Yr+c0KS 9v2oSduWaMJ/Fs3IVg5gh0bhH3lMHISqAQLtl3ncyB+1O+X+MgReRGznj5tkjQWC960t85SO hkNkhVMp0z2b1XfY51XxYRESdNkJswxv3UnpAvlgdh+ItzJU8fRmfUtOzRdGD6mukrkpkS1z lAGNLayBOiEWUk8E1gm3rK46l/sm6Gq9ExCh+bgkwQHRp/JhyHpsid9V/o5nLh+jbh/CLYIF onrG2RN6lePQpyh6TpiZfGbxz/4rny88HdCD31OdvTwbnNp5Fj48YXbUlo8WILg2OHWbSRQ9 w7OuTLcITPW084E/Uq/nL6+m316OZpY7iiVB+1e2reJRjnsqlK+TX7N1KsAamba3hGSqF8QC 61RAzXS99D1ohL98G0hJNYyuHaeWus4wJRt8JBEe6D4r0hrS/O97oa0juygwY+zP9mtpYRr4 t9Im1hpIkV+cC3aJrRiQNaXJN4S+8F8DQnXMUitf0590NNKwYRuQuTg5URoqjYBFZtXGgS7w vdyzevMt1bCBtZW6Rbdu6TcHoF3Aminx96wXlSizTGpo+xJ589xQ46U9KWXdzsFNBFm31LoB EADAsXCTRufklKBW9jdUMwjltZjXwu5muxcVRj8XICi77oa9DgsGhA5v7vosbpNXzZAL018h 1khPu6ca6X0shLm0Le2KQ6Q00VHEwrTjXQ0NN0aa+vRG3NKPb9t/SiXg6yNPKuQxTsYm0vP9 4fIH6nHDtJpBXq8LK5C6GTD6G2R3VTSPpJz6tFPrfLrV4jPARFRAZ483Wjs9iBRygFTtb6YJ r1YJnwmXcb8Z/ds3vPo5ULMcMlcXEA7NlkmN7r3LUkmE6Tjr1hZHGwEWRwSiw1CwkAQqLlMX xRul5+nPz0pPrB8hBxONjnlGX3f0Ky2xdKxrFxlzd8HtRzhWb4R0vqgWQRXXFeKc++uEyk6g KZ48zSjLq0Av4ZS8POCL1JisSV7Hbwe4Ik3qaeR61KEuVtBlySFijwvTs4p5b9PcG2fmNiyo aFBdFkbI/pTuORRBYCLbjXwyRWnCGBWZ8b0NSCs4sb9vNyObxoLYN4RdRnKKLpkXz3EXdPWZ WswxQQNopKs5pE3aAvYfTitIg0JmKSK57w3UJNS11s5xTRAmKDHj9PmLZcNLFhG7ceb9T41+ YLNCEu8/xvFEorp+AlJ6n0clfPsNsi8317ZJL0mgZ0XrD9efmuA+xvb/0T67D371qK6xDaZ2 xN71pfjhZl1OYNZ3FDJLpZSNZKNFluhRWOvTKQARAQABwsF8BBgBCAAmFiEEHW7T7ovP/cFp 8+b3DHQ+aNFTs7UFAlm31LoCGwwFCQlmAYAACgkQDHQ+aNFTs7XITg/9GHcaTLjsRP7Pacu0 PFs2ubddBvZPC19sIILUNDlQHsOVKTpuFTtEmA6F4o4gf/SY8AvnHyVVqe8YYsQkPwhwfwbH ihoDZyJxyr52mqanez3sQV6RQEqCZtKaJtMdZrtOZcjqrAxEG1arowCKnnoPF+ivtA4ZEtlm xt9x5S0UfytTIZR0KKsRfO7XZvqfzbg6/NVRnUibSzCz2yzC5kbsyjPoK+c+C142BlnCdgai 0It5xKX1BBoVT/YSeB5ACGijuRsuDH2mHzdOeEDlP/UOAB5gx9aBOdP8YMTAk2b4qfANX7Pc W8BnI99mWuOP04KVgdQf5vgwMRDlgdtsQJw7l5YBQxprq8edAH3xsKung03qsV2inbQDkMnl c+l79kx0ilh0oLwviRft5xVCOfCyVkvekUhN4qG+guGFJbxYffliFB02Kcf2e4CueCnGGZAw +OkhHbtDmgmyslv7cxf1qzsObQfYc9eR5f8uiX41bLPwTMy18YnYk2hxJSW0g+LkPqBVQcAO Nwdozk9DY6wY9cMQ8coYTctox5VsvYEz2rJCRiIc40NO76gdMVutEORjdSoeZK32srVNoBo9 L0EK2QCFFRDcslPDpZWE1uDZQPW+GC2Z/dmuEpaMzlrIgfZ8GLXxHbB+VdDQ7QE//lphXskF lHi50np+KDDPzZS51tw= Message-ID: Date: Wed, 27 Mar 2019 20:13:18 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.3 MIME-Version: 1.0 In-Reply-To: <20190326191307.GM24180@google.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [172.17.15.60] X-ClientProxiedBy: T-EXCH-01.corp.yadro.com (172.17.10.101) To T-EXCH-02.corp.yadro.com (172.17.10.102) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On 3/26/19 10:13 PM, Bjorn Helgaas wrote: > On Mon, Mar 11, 2019 at 04:31:04PM +0300, Sergey Miroshnichenko wrote: >> After updating the bridge window resources, the PCI_COMMAND_IO and >> PCI_COMMAND_MEMORY bits of the bridge must be addressed as well. >> >> Signed-off-by: Sergey Miroshnichenko >> --- >> drivers/pci/pci.c | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c >> index 895201d4c9e6..69898fe5255e 100644 >> --- a/drivers/pci/pci.c >> +++ b/drivers/pci/pci.c >> @@ -1622,6 +1622,14 @@ static void pci_enable_bridge(struct pci_dev *dev) >> pci_enable_bridge(bridge); >> >> if (pci_is_enabled(dev)) { >> + int i, bars = 0; >> + >> + for (i = PCI_BRIDGE_RESOURCES; i < DEVICE_COUNT_RESOURCE; i++) { >> + if (dev->resource[i].flags & (IORESOURCE_MEM | IORESOURCE_IO)) >> + bars |= (1 << i); >> + } >> + do_pci_enable_device(dev, bars); > > In what situation is this needed, exactly? This code already exists > in pci_enable_device_flags(). Why isn't that enough? > > I guess maybe there's some case where we enable the bridge, then > assign bridge windows, then enable a downstream device? > > Does this fix a bug with current hotplug? > Sure, this change was implemented because of the issue: pci_enable_device_flags() returns early if the device is already pci_is_enabled(), so if a bridge was already enabled before the hotplug event, but without MEM and/or IO being set, these bits will not be set even if a new device wants them. I've chosen the pci_enable_bridge() for this snippet because it recursively updates all the parent bridges. Serge >> if (!dev->is_busmaster) >> pci_set_master(dev); >> mutex_unlock(&dev->enable_mutex); >> -- >> 2.20.1 >>