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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 5FABCC43603 for ; Thu, 19 Dec 2019 11:19:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 27E9B222C2 for ; Thu, 19 Dec 2019 11:19:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726866AbfLSLT6 (ORCPT ); Thu, 19 Dec 2019 06:19:58 -0500 Received: from mx2.suse.de ([195.135.220.15]:40026 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726696AbfLSLT6 (ORCPT ); Thu, 19 Dec 2019 06:19:58 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 45C48AB91; Thu, 19 Dec 2019 11:19:56 +0000 (UTC) Subject: Re: [PATCH v2] xen-pciback: optionally allow interrupt enable flag writes To: =?UTF-8?Q?Marek_Marczykowski-G=c3=b3recki?= Cc: xen-devel@lists.xenproject.org, =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , YueHaibing , Simon Gaiser , Stefano Stabellini , Boris Ostrovsky , Juergen Gross , open list References: <20191219034941.19141-1-marmarek@invisiblethingslab.com> From: Jan Beulich Message-ID: Date: Thu, 19 Dec 2019 12:20:24 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1 MIME-Version: 1.0 In-Reply-To: <20191219034941.19141-1-marmarek@invisiblethingslab.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19.12.2019 04:49, Marek Marczykowski-Górecki wrote: > +enum interrupt_type xen_pcibk_get_interrupt_type(struct pci_dev *dev) > +{ > + int err; > + u16 val; > + > + err = pci_read_config_word(dev, PCI_COMMAND, &val); > + if (err) > + return INTERRUPT_TYPE_ERR; > + if (!(val & PCI_COMMAND_INTX_DISABLE)) > + return INTERRUPT_TYPE_INTX; > + > + /* Do not trust dev->msi(x)_enabled here, as enabling could be done > + * bypassing the pci_*msi* functions, by the qemu. > + */ Judging from this comment, how can you assume only one of the three variants is actually enabled? It's against the spec, yes, but it's not at all impossible afaict. I think you want the return value here to be - negative errno values (no need to discard the actual error codes) or - a non-negative bitmap indicating which of the interrupt types is/are currently enabled. That way ... > +static int msi_msix_flags_write(struct pci_dev *dev, int offset, u16 new_value, > + void *data) > +{ > + int err; > + u16 old_value; > + const struct msi_msix_field_config *field_config = data; > + const struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev); > + > + if (xen_pcibk_permissive || dev_data->permissive) > + goto write; > + > + err = pci_read_config_word(dev, offset, &old_value); > + if (err) > + return err; > + > + if (new_value == old_value) > + return 0; > + > + if (!dev_data->allow_interrupt_control || > + (new_value ^ old_value) & ~field_config->enable_bit) > + return PCIBIOS_SET_FAILED; > + > + if (new_value & field_config->enable_bit) { > + /* don't allow enabling together with other interrupt types */ > + const enum interrupt_type int_type = xen_pcibk_get_interrupt_type(dev); > + if (int_type == INTERRUPT_TYPE_NONE || > + int_type == field_config->int_type) ... equality comparisons like this one will actually become safe. Jan 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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 425CDC43603 for ; Thu, 19 Dec 2019 11:20:18 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 1B36C222C2 for ; Thu, 19 Dec 2019 11:20:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B36C222C2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1ihtqh-0005g1-Gs; Thu, 19 Dec 2019 11:20:07 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1ihtqg-0005ew-58 for xen-devel@lists.xenproject.org; Thu, 19 Dec 2019 11:20:06 +0000 X-Inumbo-ID: 7cba7a80-2251-11ea-b6f1-bc764e2007e4 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 7cba7a80-2251-11ea-b6f1-bc764e2007e4; Thu, 19 Dec 2019 11:19:57 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 45C48AB91; Thu, 19 Dec 2019 11:19:56 +0000 (UTC) To: =?UTF-8?Q?Marek_Marczykowski-G=c3=b3recki?= References: <20191219034941.19141-1-marmarek@invisiblethingslab.com> From: Jan Beulich Message-ID: Date: Thu, 19 Dec 2019 12:20:24 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1 MIME-Version: 1.0 In-Reply-To: <20191219034941.19141-1-marmarek@invisiblethingslab.com> Content-Language: en-US Subject: Re: [Xen-devel] [PATCH v2] xen-pciback: optionally allow interrupt enable flag writes X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Juergen Gross , Stefano Stabellini , YueHaibing , open list , Simon Gaiser , xen-devel@lists.xenproject.org, Boris Ostrovsky , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" T24gMTkuMTIuMjAxOSAwNDo0OSwgTWFyZWsgTWFyY3p5a293c2tpLUfDs3JlY2tpICB3cm90ZToK PiArZW51bSBpbnRlcnJ1cHRfdHlwZSB4ZW5fcGNpYmtfZ2V0X2ludGVycnVwdF90eXBlKHN0cnVj dCBwY2lfZGV2ICpkZXYpCj4gK3sKPiArCWludCBlcnI7Cj4gKwl1MTYgdmFsOwo+ICsKPiArCWVy ciA9IHBjaV9yZWFkX2NvbmZpZ193b3JkKGRldiwgUENJX0NPTU1BTkQsICZ2YWwpOwo+ICsJaWYg KGVycikKPiArCQlyZXR1cm4gSU5URVJSVVBUX1RZUEVfRVJSOwo+ICsJaWYgKCEodmFsICYgUENJ X0NPTU1BTkRfSU5UWF9ESVNBQkxFKSkKPiArCQlyZXR1cm4gSU5URVJSVVBUX1RZUEVfSU5UWDsK PiArCj4gKwkvKiBEbyBub3QgdHJ1c3QgZGV2LT5tc2koeClfZW5hYmxlZCBoZXJlLCBhcyBlbmFi bGluZyBjb3VsZCBiZSBkb25lCj4gKwkgKiBieXBhc3NpbmcgdGhlIHBjaV8qbXNpKiBmdW5jdGlv bnMsIGJ5IHRoZSBxZW11Lgo+ICsJICovCgpKdWRnaW5nIGZyb20gdGhpcyBjb21tZW50LCBob3cg Y2FuIHlvdSBhc3N1bWUgb25seSBvbmUgb2YgdGhlCnRocmVlIHZhcmlhbnRzIGlzIGFjdHVhbGx5 IGVuYWJsZWQ/IEl0J3MgYWdhaW5zdCB0aGUgc3BlYywgeWVzLApidXQgaXQncyBub3QgYXQgYWxs IGltcG9zc2libGUgYWZhaWN0LiBJIHRoaW5rIHlvdSB3YW50IHRoZQpyZXR1cm4gdmFsdWUgaGVy ZSB0byBiZQotIG5lZ2F0aXZlIGVycm5vIHZhbHVlcyAobm8gbmVlZCB0byBkaXNjYXJkIHRoZSBh Y3R1YWwgZXJyb3IKICBjb2Rlcykgb3IKLSBhIG5vbi1uZWdhdGl2ZSBiaXRtYXAgaW5kaWNhdGlu ZyB3aGljaCBvZiB0aGUgaW50ZXJydXB0IHR5cGVzCiAgaXMvYXJlIGN1cnJlbnRseSBlbmFibGVk LgpUaGF0IHdheSAuLi4KCj4gK3N0YXRpYyBpbnQgbXNpX21zaXhfZmxhZ3Nfd3JpdGUoc3RydWN0 IHBjaV9kZXYgKmRldiwgaW50IG9mZnNldCwgdTE2IG5ld192YWx1ZSwKPiArCQkJCXZvaWQgKmRh dGEpCj4gK3sKPiArCWludCBlcnI7Cj4gKwl1MTYgb2xkX3ZhbHVlOwo+ICsJY29uc3Qgc3RydWN0 IG1zaV9tc2l4X2ZpZWxkX2NvbmZpZyAqZmllbGRfY29uZmlnID0gZGF0YTsKPiArCWNvbnN0IHN0 cnVjdCB4ZW5fcGNpYmtfZGV2X2RhdGEgKmRldl9kYXRhID0gcGNpX2dldF9kcnZkYXRhKGRldik7 Cj4gKwo+ICsJaWYgKHhlbl9wY2lia19wZXJtaXNzaXZlIHx8IGRldl9kYXRhLT5wZXJtaXNzaXZl KQo+ICsJCWdvdG8gd3JpdGU7Cj4gKwo+ICsJZXJyID0gcGNpX3JlYWRfY29uZmlnX3dvcmQoZGV2 LCBvZmZzZXQsICZvbGRfdmFsdWUpOwo+ICsJaWYgKGVycikKPiArCQlyZXR1cm4gZXJyOwo+ICsK PiArCWlmIChuZXdfdmFsdWUgPT0gb2xkX3ZhbHVlKQo+ICsJCXJldHVybiAwOwo+ICsKPiArCWlm ICghZGV2X2RhdGEtPmFsbG93X2ludGVycnVwdF9jb250cm9sIHx8Cj4gKwkgICAgKG5ld192YWx1 ZSBeIG9sZF92YWx1ZSkgJiB+ZmllbGRfY29uZmlnLT5lbmFibGVfYml0KQo+ICsJCXJldHVybiBQ Q0lCSU9TX1NFVF9GQUlMRUQ7Cj4gKwo+ICsJaWYgKG5ld192YWx1ZSAmIGZpZWxkX2NvbmZpZy0+ ZW5hYmxlX2JpdCkgewo+ICsJCS8qIGRvbid0IGFsbG93IGVuYWJsaW5nIHRvZ2V0aGVyIHdpdGgg b3RoZXIgaW50ZXJydXB0IHR5cGVzICovCj4gKwkJY29uc3QgZW51bSBpbnRlcnJ1cHRfdHlwZSBp bnRfdHlwZSA9IHhlbl9wY2lia19nZXRfaW50ZXJydXB0X3R5cGUoZGV2KTsKPiArCQlpZiAoaW50 X3R5cGUgPT0gSU5URVJSVVBUX1RZUEVfTk9ORSB8fAo+ICsJCSAgICBpbnRfdHlwZSA9PSBmaWVs ZF9jb25maWctPmludF90eXBlKQoKLi4uIGVxdWFsaXR5IGNvbXBhcmlzb25zIGxpa2UgdGhpcyBv bmUgd2lsbCBhY3R1YWxseSBiZWNvbWUgc2FmZS4KCkphbgoKX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX18KWGVuLWRldmVsIG1haWxpbmcgbGlzdApYZW4tZGV2 ZWxAbGlzdHMueGVucHJvamVjdC5vcmcKaHR0cHM6Ly9saXN0cy54ZW5wcm9qZWN0Lm9yZy9tYWls bWFuL2xpc3RpbmZvL3hlbi1kZXZlbA==