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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 B7C4CC43141 for ; Fri, 29 Nov 2019 17:27:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 933612176D for ; Fri, 29 Nov 2019 17:27:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727508AbfK2R1E (ORCPT ); Fri, 29 Nov 2019 12:27:04 -0500 Received: from ale.deltatee.com ([207.54.116.67]:35734 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726957AbfK2R1E (ORCPT ); Fri, 29 Nov 2019 12:27:04 -0500 Received: from s0106ac1f6bb1ecac.cg.shawcable.net ([70.73.163.230] helo=[192.168.11.155]) by ale.deltatee.com with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1iak2k-0008Lo-N5; Fri, 29 Nov 2019 10:26:59 -0700 To: James Sewart Cc: linux-pci@vger.kernel.org, Christoph Hellwig , Dmitry Safonov <0x7f454c46@gmail.com>, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Dmitry Safonov , Alex Williamson , Bjorn Helgaas References: <20191120193228.GA103670@google.com> <6A902F0D-FE98-4760-ADBB-4D5987D866BE@arista.com> <20191126173833.GA16069@infradead.org> <547214A9-9FD0-4DD5-80E1-1F5A467A0913@arista.com> <9c54c5dd-702c-a19b-38ba-55ab73b24729@deltatee.com> <435064D4-00F0-47F5-94D2-2C354F6B1206@arista.com> <058383d9-69fe-65e3-e410-eebd99840261@deltatee.com> From: Logan Gunthorpe Message-ID: Date: Fri, 29 Nov 2019 10:26:57 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 70.73.163.230 X-SA-Exim-Rcpt-To: helgaas@kernel.org, alex.williamson@redhat.com, dima@arista.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, 0x7f454c46@gmail.com, hch@infradead.org, linux-pci@vger.kernel.org, jamessewart@arista.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v4 1/2] PCI: Add parameter nr_devfns to pci_add_dma_alias X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019-11-29 10:19 a.m., James Sewart wrote: > > >> On 29 Nov 2019, at 16:50, Logan Gunthorpe wrote: >> >> >> >> On 2019-11-29 5:49 a.m., James Sewart wrote: >>> pci_add_dma_alias can now be used to create a dma alias for a range of >>> devfns. >>> >>> Signed-off-by: James Sewart >>> --- >>> drivers/pci/pci.c | 23 ++++++++++++++++++----- >>> drivers/pci/quirks.c | 14 +++++++------- >>> include/linux/pci.h | 2 +- >>> 3 files changed, 26 insertions(+), 13 deletions(-) >>> >>> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c >>> index a97e2571a527..9b0e3481fe17 100644 >>> --- a/drivers/pci/pci.c >>> +++ b/drivers/pci/pci.c >>> @@ -5857,7 +5857,8 @@ int pci_set_vga_state(struct pci_dev *dev, bool decode, >>> /** >>> * pci_add_dma_alias - Add a DMA devfn alias for a device >>> * @dev: the PCI device for which alias is added >>> - * @devfn: alias slot and function >>> + * @devfn_from: alias slot and function >>> + * @nr_devfns: Number of subsequent devfns to alias >>> * >>> * This helper encodes an 8-bit devfn as a bit number in dma_alias_mask >>> * which is used to program permissible bus-devfn source addresses for DMA >>> @@ -5873,8 +5874,14 @@ int pci_set_vga_state(struct pci_dev *dev, bool decode, >>> * cannot be left as a userspace activity). DMA aliases should therefore >>> * be configured via quirks, such as the PCI fixup header quirk. >>> */ >>> -void pci_add_dma_alias(struct pci_dev *dev, u8 devfn) >>> +void pci_add_dma_alias(struct pci_dev *dev, u8 devfn_from, unsigned nr_devfns) >>> { >>> + int devfn_to; >>> + >>> + if (nr_devfns > U8_MAX+1) >>> + nr_devfns = U8_MAX+1; >> >> Why +1? That doesn't seem right to me…. > > U8_MAX is the max number U8 can represent(255) but is one less than the number > of values it can represent(256). devfns can be 0.0 to 1f.7 inclusive(I think) > so the number of possible devfns is 256. Thinking about it, maybe the > zalloc should be U8_MAX+1 too? > > I might be wrong though, what do you reckon? Right, yes, but I actually think the original code is wrong. It's only allocating a bitmap that holds 255 values and you're trying to insert 256 ones into that bitmap. It's probably ok, because there's no way to allocate an odd sized bitmap, but it's probably worth fixing for clarity. It also looks wrong in pci_for_each_dma_alias() as well, so I'd probably fix both those up in a separate prep-patch. Logan 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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 8DBC4C432C3 for ; Fri, 29 Nov 2019 17:27:05 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (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 633252176D for ; Fri, 29 Nov 2019 17:27:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 633252176D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=deltatee.com Authentication-Results: mail.kernel.org; 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Fri, 29 Nov 2019 17:27:02 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id p1orB2erOvMg for ; Fri, 29 Nov 2019 17:27:01 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from ale.deltatee.com (ale.deltatee.com [207.54.116.67]) by whitealder.osuosl.org (Postfix) with ESMTPS id 2018687E38 for ; Fri, 29 Nov 2019 17:27:01 +0000 (UTC) Received: from s0106ac1f6bb1ecac.cg.shawcable.net ([70.73.163.230] helo=[192.168.11.155]) by ale.deltatee.com with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1iak2k-0008Lo-N5; Fri, 29 Nov 2019 10:26:59 -0700 To: James Sewart References: <20191120193228.GA103670@google.com> <6A902F0D-FE98-4760-ADBB-4D5987D866BE@arista.com> <20191126173833.GA16069@infradead.org> <547214A9-9FD0-4DD5-80E1-1F5A467A0913@arista.com> <9c54c5dd-702c-a19b-38ba-55ab73b24729@deltatee.com> <435064D4-00F0-47F5-94D2-2C354F6B1206@arista.com> <058383d9-69fe-65e3-e410-eebd99840261@deltatee.com> From: Logan Gunthorpe Message-ID: Date: Fri, 29 Nov 2019 10:26:57 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-SA-Exim-Connect-IP: 70.73.163.230 X-SA-Exim-Rcpt-To: helgaas@kernel.org, alex.williamson@redhat.com, dima@arista.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, 0x7f454c46@gmail.com, hch@infradead.org, linux-pci@vger.kernel.org, jamessewart@arista.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v4 1/2] PCI: Add parameter nr_devfns to pci_add_dma_alias X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Cc: Alex Williamson , Dmitry Safonov , linux-pci@vger.kernel.org, Dmitry Safonov <0x7f454c46@gmail.com>, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Bjorn Helgaas X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" CgpPbiAyMDE5LTExLTI5IDEwOjE5IGEubS4sIEphbWVzIFNld2FydCB3cm90ZToKPiAKPiAKPj4g T24gMjkgTm92IDIwMTksIGF0IDE2OjUwLCBMb2dhbiBHdW50aG9ycGUgPGxvZ2FuZ0BkZWx0YXRl ZS5jb20+IHdyb3RlOgo+Pgo+Pgo+Pgo+PiBPbiAyMDE5LTExLTI5IDU6NDkgYS5tLiwgSmFtZXMg U2V3YXJ0IHdyb3RlOgo+Pj4gcGNpX2FkZF9kbWFfYWxpYXMgY2FuIG5vdyBiZSB1c2VkIHRvIGNy ZWF0ZSBhIGRtYSBhbGlhcyBmb3IgYSByYW5nZSBvZgo+Pj4gZGV2Zm5zLgo+Pj4KPj4+IFNpZ25l ZC1vZmYtYnk6IEphbWVzIFNld2FydCA8amFtZXNzZXdhcnRAYXJpc3RhLmNvbT4KPj4+IC0tLQo+ Pj4gZHJpdmVycy9wY2kvcGNpLmMgICAgfCAyMyArKysrKysrKysrKysrKysrKystLS0tLQo+Pj4g ZHJpdmVycy9wY2kvcXVpcmtzLmMgfCAxNCArKysrKysrLS0tLS0tLQo+Pj4gaW5jbHVkZS9saW51 eC9wY2kuaCAgfCAgMiArLQo+Pj4gMyBmaWxlcyBjaGFuZ2VkLCAyNiBpbnNlcnRpb25zKCspLCAx MyBkZWxldGlvbnMoLSkKPj4+Cj4+PiBkaWZmIC0tZ2l0IGEvZHJpdmVycy9wY2kvcGNpLmMgYi9k cml2ZXJzL3BjaS9wY2kuYwo+Pj4gaW5kZXggYTk3ZTI1NzFhNTI3Li45YjBlMzQ4MWZlMTcgMTAw NjQ0Cj4+PiAtLS0gYS9kcml2ZXJzL3BjaS9wY2kuYwo+Pj4gKysrIGIvZHJpdmVycy9wY2kvcGNp LmMKPj4+IEBAIC01ODU3LDcgKzU4NTcsOCBAQCBpbnQgcGNpX3NldF92Z2Ffc3RhdGUoc3RydWN0 IHBjaV9kZXYgKmRldiwgYm9vbCBkZWNvZGUsCj4+PiAvKioKPj4+ICAqIHBjaV9hZGRfZG1hX2Fs aWFzIC0gQWRkIGEgRE1BIGRldmZuIGFsaWFzIGZvciBhIGRldmljZQo+Pj4gICogQGRldjogdGhl IFBDSSBkZXZpY2UgZm9yIHdoaWNoIGFsaWFzIGlzIGFkZGVkCj4+PiAtICogQGRldmZuOiBhbGlh cyBzbG90IGFuZCBmdW5jdGlvbgo+Pj4gKyAqIEBkZXZmbl9mcm9tOiBhbGlhcyBzbG90IGFuZCBm dW5jdGlvbgo+Pj4gKyAqIEBucl9kZXZmbnM6IE51bWJlciBvZiBzdWJzZXF1ZW50IGRldmZucyB0 byBhbGlhcwo+Pj4gICoKPj4+ICAqIFRoaXMgaGVscGVyIGVuY29kZXMgYW4gOC1iaXQgZGV2Zm4g YXMgYSBiaXQgbnVtYmVyIGluIGRtYV9hbGlhc19tYXNrCj4+PiAgKiB3aGljaCBpcyB1c2VkIHRv IHByb2dyYW0gcGVybWlzc2libGUgYnVzLWRldmZuIHNvdXJjZSBhZGRyZXNzZXMgZm9yIERNQQo+ Pj4gQEAgLTU4NzMsOCArNTg3NCwxNCBAQCBpbnQgcGNpX3NldF92Z2Ffc3RhdGUoc3RydWN0IHBj aV9kZXYgKmRldiwgYm9vbCBkZWNvZGUsCj4+PiAgKiBjYW5ub3QgYmUgbGVmdCBhcyBhIHVzZXJz cGFjZSBhY3Rpdml0eSkuICBETUEgYWxpYXNlcyBzaG91bGQgdGhlcmVmb3JlCj4+PiAgKiBiZSBj b25maWd1cmVkIHZpYSBxdWlya3MsIHN1Y2ggYXMgdGhlIFBDSSBmaXh1cCBoZWFkZXIgcXVpcmsu Cj4+PiAgKi8KPj4+IC12b2lkIHBjaV9hZGRfZG1hX2FsaWFzKHN0cnVjdCBwY2lfZGV2ICpkZXYs IHU4IGRldmZuKQo+Pj4gK3ZvaWQgcGNpX2FkZF9kbWFfYWxpYXMoc3RydWN0IHBjaV9kZXYgKmRl diwgdTggZGV2Zm5fZnJvbSwgdW5zaWduZWQgbnJfZGV2Zm5zKQo+Pj4gewo+Pj4gKwlpbnQgZGV2 Zm5fdG87Cj4+PiArCj4+PiArCWlmIChucl9kZXZmbnMgPiBVOF9NQVgrMSkKPj4+ICsJCW5yX2Rl dmZucyA9IFU4X01BWCsxOwo+Pgo+PiBXaHkgKzE/IFRoYXQgZG9lc24ndCBzZWVtIHJpZ2h0IHRv IG1l4oCmLgo+IAo+IFU4X01BWCBpcyB0aGUgbWF4IG51bWJlciBVOCBjYW4gcmVwcmVzZW50KDI1 NSkgYnV0IGlzIG9uZSBsZXNzIHRoYW4gdGhlIG51bWJlciAKPiBvZiB2YWx1ZXMgaXQgY2FuIHJl cHJlc2VudCgyNTYpLiBkZXZmbnMgY2FuIGJlIDAuMCB0byAxZi43IGluY2x1c2l2ZShJIHRoaW5r KSAKPiBzbyB0aGUgbnVtYmVyIG9mIHBvc3NpYmxlIGRldmZucyBpcyAyNTYuIFRoaW5raW5nIGFi b3V0IGl0LCBtYXliZSB0aGUgCj4gemFsbG9jIHNob3VsZCBiZSBVOF9NQVgrMSB0b28/Cj4gCj4g SSBtaWdodCBiZSB3cm9uZyB0aG91Z2gsIHdoYXQgZG8geW91IHJlY2tvbj8KClJpZ2h0LCB5ZXMs IGJ1dCBJIGFjdHVhbGx5IHRoaW5rIHRoZSBvcmlnaW5hbCBjb2RlIGlzIHdyb25nLiBJdCdzIG9u bHkKYWxsb2NhdGluZyBhIGJpdG1hcCB0aGF0IGhvbGRzIDI1NSB2YWx1ZXMgYW5kIHlvdSdyZSB0 cnlpbmcgdG8gaW5zZXJ0CjI1NiBvbmVzIGludG8gdGhhdCBiaXRtYXAuIEl0J3MgcHJvYmFibHkg b2ssIGJlY2F1c2UgdGhlcmUncyBubyB3YXkgdG8KYWxsb2NhdGUgYW4gb2RkIHNpemVkIGJpdG1h cCwgYnV0IGl0J3MgcHJvYmFibHkgd29ydGggZml4aW5nIGZvciBjbGFyaXR5LgoKSXQgYWxzbyBs b29rcyB3cm9uZyBpbiBwY2lfZm9yX2VhY2hfZG1hX2FsaWFzKCkgYXMgd2VsbCwgc28gSSdkIHBy b2JhYmx5CmZpeCBib3RoIHRob3NlIHVwIGluIGEgc2VwYXJhdGUgcHJlcC1wYXRjaC4KCkxvZ2Fu Cl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCmlvbW11IG1h aWxpbmcgbGlzdAppb21tdUBsaXN0cy5saW51eC1mb3VuZGF0aW9uLm9yZwpodHRwczovL2xpc3Rz LmxpbnV4Zm91bmRhdGlvbi5vcmcvbWFpbG1hbi9saXN0aW5mby9pb21tdQ==