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mx.microsoft.com 1; spf=none; dmarc=none; dkim=none; arc=none Received: from SG2APC01FT052.eop-APC01.prod.protection.outlook.com (10.152.250.58) by SG2APC01HT059.eop-APC01.prod.protection.outlook.com (10.152.251.7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2451.23; Mon, 18 Nov 2019 09:43:34 +0000 Received: from PS2P216MB0755.KORP216.PROD.OUTLOOK.COM (10.152.250.57) by SG2APC01FT052.mail.protection.outlook.com (10.152.251.14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2451.23 via Frontend Transport; Mon, 18 Nov 2019 09:43:34 +0000 Received: from PS2P216MB0755.KORP216.PROD.OUTLOOK.COM ([fe80::44f5:f4bb:1601:2602]) by PS2P216MB0755.KORP216.PROD.OUTLOOK.COM ([fe80::44f5:f4bb:1601:2602%9]) with mapi id 15.20.2451.029; Mon, 18 Nov 2019 09:43:34 +0000 From: Nicholas Johnson To: Bjorn Helgaas CC: "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , "mika.westerberg@linux.intel.com" , "corbet@lwn.net" , "benh@kernel.crashing.org" , "logang@deltatee.com" Subject: Re: [PATCH v3 1/1] PCI: Fix bug resulting in double hpmemsize being assigned to MMIO window Thread-Topic: [PATCH v3 1/1] PCI: Fix bug resulting in double hpmemsize being assigned to MMIO window Thread-Index: AQHVmjaUpBZrOiNs+EaePGmphxD+QaeK5IeAgAXQSwA= Date: Mon, 18 Nov 2019 09:43:34 +0000 Message-ID: References: <20191114165637.GA210407@google.com> In-Reply-To: <20191114165637.GA210407@google.com> Accept-Language: en-AU, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-clientproxiedby: SYBPR01CA0112.ausprd01.prod.outlook.com (2603:10c6:10:1::28) To PS2P216MB0755.KORP216.PROD.OUTLOOK.COM (2603:1096:300:1c::13) x-incomingtopheadermarker: OriginalChecksum:7FB88D3606022236447AE83E1521C51EF602EF044E51F6FAF466BA32A82E88DC;UpperCasedChecksum:36BEE5EE6BB7962D344A753D4E325969A517CCCD25ACE6E585A17E54174484D7;SizeAsReceived:7829;Count:49 x-ms-exchange-messagesentrepresentingtype: 1 x-tmn: [OqRBEytzFILu8M81jd58mPHbpfhyw1gHdSMytM3FbuJ7uBVwgqpXggf4zjRqnF+Hwl7G+Vp+Hb8=] x-microsoft-original-message-id: <20191118094326.GA2194@nicholas-dell-linux> x-ms-publictraffictype: Email x-incomingheadercount: 49 x-eopattributedmessage: 0 x-ms-office365-filtering-correlation-id: 45a23db3-a5e8-4fa6-fde4-08d76c0bc70b x-ms-traffictypediagnostic: SG2APC01HT059: x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: WDXEcv6bzn6imJE46d8zC31ck+Ev2hNPp5YhYGxu4QlmbhgzkOd3gbf76l0SR6YcTDLzqF6Zw5ie+/fXEXz5VNiHxNJrw4FoQZCtesRhu/644K7Bkp9EZKvzayvaLI+XdMfydAUFjVy6o4oIHNc0C/1Jt1lspgTFvvpgIHQS3N5wjrZRU1Nn4rg1Jy2FRYPy x-ms-exchange-transport-forked: True Content-Type: text/plain; charset="us-ascii" Content-ID: Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-OriginatorOrg: outlook.com X-MS-Exchange-CrossTenant-RMS-PersistedConsumerOrg: 00000000-0000-0000-0000-000000000000 X-MS-Exchange-CrossTenant-Network-Message-Id: 45a23db3-a5e8-4fa6-fde4-08d76c0bc70b X-MS-Exchange-CrossTenant-rms-persistedconsumerorg: 00000000-0000-0000-0000-000000000000 X-MS-Exchange-CrossTenant-originalarrivaltime: 18 Nov 2019 09:43:34.5932 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Internet X-MS-Exchange-CrossTenant-id: 84df9e7f-e9f6-40af-b435-aaaaaaaaaaaa X-MS-Exchange-Transport-CrossTenantHeadersStamped: SG2APC01HT059 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thu, Nov 14, 2019 at 10:56:37AM -0600, Bjorn Helgaas wrote: > On Wed, Nov 13, 2019 at 03:25:28PM +0000, Nicholas Johnson wrote: > > Currently, the kernel can sometimes assign the MMIO_PREF window > > additional size into the MMIO window, resulting in extra MMIO additional > > size, despite the MMIO_PREF additional size being assigned successfully > > into the MMIO_PREF window. > > > > This happens if in the first pass, the MMIO_PREF succeeds but the MMIO > > fails. In the next pass, because MMIO_PREF is already assigned, the > > attempt to assign MMIO_PREF returns an error code instead of success > > (nothing more to do, already allocated). Hence, the size which is > > actually allocated, but thought to have failed, is placed in the MMIO > > window. > > > > Example of problem (more context can be found in the bug report URL): > > > > Mainline kernel: > > pci 0000:06:01.0: BAR 14: assigned [mem 0x90100000-0xa00fffff] = 256M > > pci 0000:06:04.0: BAR 14: assigned [mem 0xa0200000-0xb01fffff] = 256M > > > > Patched kernel: > > pci 0000:06:01.0: BAR 14: assigned [mem 0x90100000-0x980fffff] = 128M > > pci 0000:06:04.0: BAR 14: assigned [mem 0x98200000-0xa01fffff] = 128M > > > > This was using pci=realloc,hpmemsize=128M,nocrs - on the same machine > > with the same configuration, with a Ubuntu mainline kernel and a kernel > > patched with this patch. > > > > The bug results in the MMIO_PREF being added to the MMIO window, which > > means doubling if MMIO_PREF size = MMIO size. With a large MMIO_PREF, > > the MMIO window will likely fail to be assigned altogether due to lack > > of 32-bit address space. > > > > Change find_free_bus_resource() to do the following: > > - Return first unassigned resource of the correct type. > > - If none of the above, return first assigned resource of the correct type. > > - If none of the above, return NULL. > > > > Returning an assigned resource of the correct type allows the caller to > > distinguish between already assigned and no resource of the correct type. > > > > Rename find_free_bus_resource to find_bus_resource_of_type(). > > > > Add checks in pbus_size_io() and pbus_size_mem() to return success if > > resource returned from find_free_bus_resource() is already allocated. > > > > This avoids pbus_size_io() and pbus_size_mem() returning error code to > > __pci_bus_size_bridges() when a resource has been successfully assigned > > in a previous pass. This fixes the existing behaviour where space for a > > resource could be reserved multiple times in different parent bridge > > windows. > > > > Link: https://lore.kernel.org/lkml/20190531171216.20532-2-logang@deltatee.com/T/#u > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=203243 > > > > Reported-by: Kit Chow > > Reported-by: Nicholas Johnson > > Signed-off-by: Nicholas Johnson > > Reviewed-by: Mika Westerberg > > Applied with reviewed-by from Mika and Logan to pci/resource for v5.5, > thanks! We have v5.4-rc8, so there is one more week. Please let me know if you have any concerns about the other four patches so that I may address them ASAP. If you are worried about the first one, I can re-post the series with it at the end, so that the others can be taken first. Thanks! Regards, Nicholas > > > --- > > drivers/pci/setup-bus.c | 38 +++++++++++++++++++++++++++----------- > > 1 file changed, 27 insertions(+), 11 deletions(-) > > > > diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c > > index 6b64bf909..f382f449b 100644 > > --- a/drivers/pci/setup-bus.c > > +++ b/drivers/pci/setup-bus.c > > @@ -752,24 +752,32 @@ static void pci_bridge_check_ranges(struct pci_bus *bus) > > } > > > > /* > > - * Helper function for sizing routines: find first available bus resource > > - * of a given type. Note: we intentionally skip the bus resources which > > - * have already been assigned (that is, have non-NULL parent resource). > > + * Helper function for sizing routines. > > + * Assigned resources have non-NULL parent resource. > > + * > > + * Return first unassigned resource of the correct type. > > + * If none of the above, return first assigned resource of the correct type. > > + * If none of the above, return NULL. > > + * > > + * Returning an assigned resource of the correct type allows the caller to > > + * distinguish between already assigned and no resource of the correct type. > > */ > > -static struct resource *find_free_bus_resource(struct pci_bus *bus, > > - unsigned long type_mask, > > - unsigned long type) > > +static struct resource *find_bus_resource_of_type(struct pci_bus *bus, > > + unsigned long type_mask, > > + unsigned long type) > > { > > + struct resource *r, *r_assigned = NULL; > > int i; > > - struct resource *r; > > > > pci_bus_for_each_resource(bus, r, i) { > > if (r == &ioport_resource || r == &iomem_resource) > > continue; > > if (r && (r->flags & type_mask) == type && !r->parent) > > return r; > > + if (r && (r->flags & type_mask) == type && !r_assigned) > > + r_assigned = r; > > } > > - return NULL; > > + return r_assigned; > > } > > > > static resource_size_t calculate_iosize(resource_size_t size, > > @@ -866,8 +874,8 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size, > > struct list_head *realloc_head) > > { > > struct pci_dev *dev; > > - struct resource *b_res = find_free_bus_resource(bus, IORESOURCE_IO, > > - IORESOURCE_IO); > > + struct resource *b_res = find_bus_resource_of_type(bus, IORESOURCE_IO, > > + IORESOURCE_IO); > > resource_size_t size = 0, size0 = 0, size1 = 0; > > resource_size_t children_add_size = 0; > > resource_size_t min_align, align; > > @@ -875,6 +883,10 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size, > > if (!b_res) > > return; > > > > + /* If resource is already assigned, nothing more to do. */ > > + if (b_res->parent) > > + return; > > + > > min_align = window_alignment(bus, IORESOURCE_IO); > > list_for_each_entry(dev, &bus->devices, bus_list) { > > int i; > > @@ -978,7 +990,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, > > resource_size_t min_align, align, size, size0, size1; > > resource_size_t aligns[18]; /* Alignments from 1MB to 128GB */ > > int order, max_order; > > - struct resource *b_res = find_free_bus_resource(bus, > > + struct resource *b_res = find_bus_resource_of_type(bus, > > mask | IORESOURCE_PREFETCH, type); > > resource_size_t children_add_size = 0; > > resource_size_t children_add_align = 0; > > @@ -987,6 +999,10 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, > > if (!b_res) > > return -ENOSPC; > > > > + /* If resource is already assigned, nothing more to do. */ > > + if (b_res->parent) > > + return 0; > > + > > memset(aligns, 0, sizeof(aligns)); > > max_order = 0; > > size = 0; > > -- > > 2.24.0 > >