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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 CD07DC433B4 for ; Thu, 29 Apr 2021 19:47:13 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 387A8613C1 for ; Thu, 29 Apr 2021 19:47:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 387A8613C1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id A34734B390; Thu, 29 Apr 2021 15:47:12 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@redhat.com Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id nlt7qWw9yGCj; Thu, 29 Apr 2021 15:47:11 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 793FE4B321; Thu, 29 Apr 2021 15:47:11 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 76CED4B2BE for ; Thu, 29 Apr 2021 15:47:10 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id fRKvVuapqXla for ; Thu, 29 Apr 2021 15:47:09 -0400 (EDT) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 887A64B2AB for ; Thu, 29 Apr 2021 15:47:09 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619725629; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+M4to1dcOs700isxx4oGCjHBz32mVchtGZDofF69pWA=; b=OVpFVCfri1gk3LLJ2mNIW7M5jv/n5AM+DXBF5DO3457+spy4TNXT4vdC3tG0eExinkCamx 9knIKR64U7TKa24djGNkD+GW8r/+i1aJRsy0ueea6/+P7oSDTfemMW5TJ5cjkwSO+9b//e oO2weDWiAmWWSNGP/Yubs1HbFJIA0VY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-79-KamNEiW9NsGsTkhGWHaQ0w-1; Thu, 29 Apr 2021 15:47:02 -0400 X-MC-Unique: KamNEiW9NsGsTkhGWHaQ0w-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9E7048189C6; Thu, 29 Apr 2021 19:47:00 +0000 (UTC) Received: from redhat.com (ovpn-113-225.phx2.redhat.com [10.3.113.225]) by smtp.corp.redhat.com (Postfix) with ESMTP id C2AFF69513; Thu, 29 Apr 2021 19:46:59 +0000 (UTC) Date: Thu, 29 Apr 2021 13:46:59 -0600 From: Alex Williamson To: Shanker R Donthineni Subject: Re: [RFC 1/2] vfio/pci: keep the prefetchable attribute of a BAR region in VMA Message-ID: <20210429134659.321a5c3c@redhat.com> In-Reply-To: <470360a7-0242-9ae5-816f-13608f957bf6@nvidia.com> References: <20210429162906.32742-1-sdonthineni@nvidia.com> <20210429162906.32742-2-sdonthineni@nvidia.com> <20210429122840.4f98f78e@redhat.com> <470360a7-0242-9ae5-816f-13608f957bf6@nvidia.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Cc: kvm@vger.kernel.org, Marc Zyngier , linux-kernel@vger.kernel.org, Vikram Sethi , Catalin Marinas , Jason Sequeira , Will Deacon , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu T24gVGh1LCAyOSBBcHIgMjAyMSAxNDoxNDo1MCAtMDUwMApTaGFua2VyIFIgRG9udGhpbmVuaSA8 c2RvbnRoaW5lbmlAbnZpZGlhLmNvbT4gd3JvdGU6Cgo+IFRoYW5rcyBBbGV4IGZvciBxdWljayBy ZXBseS4KPiAKPiBPbiA0LzI5LzIxIDE6MjggUE0sIEFsZXggV2lsbGlhbXNvbiB3cm90ZToKPiA+ IElmIHRoaXMgd2VyZSBhIHZhbGlkIHRoaW5nIHRvIGRvLCBpdCBzaG91bGQgYmUgZG9uZSBmb3Ig YWxsCj4gPiBhcmNoaXRlY3R1cmVzLCBub3QganVzdCBBUk02NC4gIEhvd2V2ZXIsIGEgcHJlZmV0 Y2hhYmxlIHJhbmdlIG9ubHkKPiA+IG5lY2Vzc2FyaWx5IGFsbG93cyBtZXJnZWQgd3JpdGVzLCB3 aGljaCBzZWVtcyBsaWtlIGEgc3Vic2V0IG9mIHRoZQo+ID4gc2VtYW50aWNzIGltcGxpZWQgYnkg YSBXQyBhdHRyaWJ1dGUsIHRoZXJlZm9yZSB0aGlzIGRvZXNuJ3Qgc2VlbQo+ID4gdW5pdmVyc2Fs bHkgdmFsaWQuCj4gPgo+ID4gSSdtIGFsc28gYSBiaXQgY29uZnVzZWQgYnkgeW91ciBwcm9ibGVt IHN0YXRlbWVudCB0aGF0IGluZGljYXRlcyB0aGF0Cj4gPiB3aXRob3V0IFdDIHlvdSdyZSBzZWVp bmcgdW5hbGlnbmVkIGFjY2Vzc2VzLCBkb2VzIHRoaXMgc3VnZ2VzdCB0aGF0Cj4gPiB5b3VyIGRy aXZlciBpcyBhY3R1YWxseSByZWx5aW5nIG9uIFdDIHNlbWFudGljcyB0byBwZXJmb3JtIG1lcmdp bmcgdG8KPiA+IGFjaGlldmUgYWxpZ25tZW50PyAgVGhhdCBzZWVtcyByYXRoZXIgbGlrZSBhIGRy aXZlciBidWcsIEknZCBleHBlY3QgVUMKPiA+IHZzIFdDIGlzIGxhcmdlbHkgYSBkaWZmZXJlbmNl IGluIHBlcmZvcm1hbmNlLCBub3QgYSBtZWFucyB0byBlbmZvcmNlCj4gPiBwcm9wZXIgZHJpdmVy IGFjY2VzcyBwYXR0ZXJucy4gIFBlciB0aGUgUENJIHNwZWMsIHRoZSBicmlkZ2UgaXRzZWxmIGNh bgo+ID4gbWVyZ2Ugd3JpdGVzIHRvIHByZWZldGNoYWJsZSBhcmVhcywgcHJlc3VtYWJseSByZWdh cmRsZXNzIG9mIHRoaXMKPiA+IHByb2Nlc3NvciBhdHRyaWJ1dGUsIHBlcmhhcHMgdGhhdCdzIHRo ZSBmZWF0dXJlIHlvdXIgZHJpdmVyIGlzIHJlbHlpbmcKPiA+IG9uIHRoYXQgbWlnaHQgYmUgbWlz c2luZyBoZXJlLiAgVGhhbmtzLCAgCj4gVGhlIGRyaXZlciB1c2VzIFdDIHNlbWFudGljcywgSXQn cyBtYXBwaW5nIFBDSSBwcmVmZXRjaGFibGUgQkFSUwo+IHVzaW5nIGlvcmVtYXBfd2MoKS7CoCBX ZSBkb24ndCBzZWUgYW55IGlzc3VlIGZvciB4ODYgYXJjaGl0ZWN0dXJlLAo+IGRyaXZlciB3b3Jr cyBmaW5lIGluIHRoZSBob3N0IGFuZCBndWVzdCBrZXJuZWwuIFRoZSBzYW1lIGRyaXZlciB3b3Jr cwo+IG9uIEFSTTY0IGtlcm5lbCBidXQgY3Jhc2hlcyBpbnNpZGUgVk0uIEdQVSBkcml2ZXIgdXNl cyB0aGUKPiBhcmNoaXRlY3R1cmUgYWdub3N0aWMgZnVuY3Rpb24gaW9yZW1hcF93YygpIGxpa2Ug b3RoZXIgZHJpdmVycy4gVGhpcwo+IGxpbWl0YXRpb24gYXBwbGllcyB0byBhbGwgdGhlIGRyaXZl cnMgaWYgdGhleSB1c2UgV0MgbWVtb3J5IGFuZAo+IGZvbGxvdyBBUk02NCBOT1JNQUwtTkMgYWNj ZXNzIHJ1bGVzLgoKeDg2IEtWTSB3b3JrcyBmb3Igb3RoZXIgcmVhc29ucywgS1ZNIHdpbGwgdHJ1 c3QgdGhlIHZDUFUgYXR0cmlidXRlcyBmb3IKdGhlIG1lbW9yeSByYW5nZSByYXRoZXIgdGhhbiBy ZWx5aW5nIG9ubHkgb24gdGhlIGhvc3QgbWFwcGluZy4KCj4gT24gQVJNNjQsIGlvcmVtYXBfd2Mo KSBpcyBtYXBwZWQgdG8gbm9uLWNhY2hlYWJsZSBtZW1vcnktdHlwZSwgbm8KPiBzaWRlIGVmZmVj dHMgb24gcmVhZHMgYW5kIHVuYWxpZ25lZCBhY2Nlc3NlcyBhcmUgYWxsb3dlZCBhcyBwZXIKPiBB Uk0tQVJNIGFyY2hpdGVjdHVyZS4gVGhlIGRyaXZlciBiZWhhdmlvciBpcyBkaWZmZXJlbnQgaW4g aG9zdCB2cwo+IGd1ZXN0IG9uIEFSTTY0LsKgCgpQZXIgdGhlIFBDSSBzcGVjLCBwcmVmZXRjaGFi bGUgbWVtb3J5IG9ubHkgbmVjZXNzYXJpbHkgYWxsb3dzIHRoZSBicmlkZ2UKdG8gbWVyZ2Ugd3Jp dGVzLiAgSSBiZWxpZXZlIHRoaXMgaXMgb25seSBhIHN1YnNldCBvZiB3aGF0IFdDIG1hcHBpbmdz CmFsbG93LCB0aGVyZWZvcmUgSSBleHBlY3QgdGhpcyBpcyBpbmNvbXBhdGlibGUgd2l0aCBkcml2 ZXJzIHRoYXQgZG8gbm90CnVzZSBXQyBtYXBwaW5ncy4KIAo+IEFSTSBDUFUgZ2VuZXJhdGluZyBh bGlnbm1lbnQgZmF1bHRzIGJlZm9yZSB0cmFuc2FjdGlvbiByZWFjaGVzIHRoZQo+IFBDSS1SQy9z d2l0Y2gvZW5kLXBvaW50LWRldmljZS4KCklmIGFuIGFsaWdubWVudCBmYXVsdCBpcyBmaXhlZCBi eSBjb25maWd1cmluZyBhIFdDIG1hcHBpbmcsIGRvZXNuJ3QKdGhhdCBzdWdnZXN0IHRoYXQgdGhl IGRyaXZlciBwZXJmb3JtZWQgYW4gdW5hbGlnbmVkIGFjY2VzcyBpdHNlbGYgYW5kCmlzIHJlbHlp bmcgb24gd3JpdGUgY29tYmluaW5nIGJ5IHRoZSBwcm9jZXNzb3IgdG8gY29ycmVjdCB0aGF0IGVy cm9yPwpUaGF0J3Mgd3JvbmcuICBGaXggdGhlIGRyaXZlciBvciBwbGVhc2Ugb2ZmZXIgYW5vdGhl ciBleHBsYW5hdGlvbiBvZgpob3cgdGhlIFdDIG1hcHBpbmcgcmVzb2x2ZXMgdGhpcy4gIEkgc3Vz cGVjdCB5b3UgY291bGQgZW5hYmxlIHRyYWNpbmcKaW4gUUVNVSwgZGlzYWJsZSBNTUlPIG1tYXBz IG9uIHRoZSB2ZmlvLXBjaSBkZXZpY2UgYW5kIGZpbmQgdGhlIGludmFsaWQKYWNjZXNzLgoKPiBX ZSd2ZSB0d28gY29uY2VybnMgaGVyZToKPiDCoMKgIC0gUGVyZm9ybWFuY2UgaW1wYWN0cyBmb3Ig cGFzcy10aHJvdWdoIGRldmljZXMuCj4gwqDCoCAtIFRoZSBkZWZpbml0aW9uIG9mIGlvcmVtYXBf d2MoKSBmdW5jdGlvbiBkb2Vzbid0IG1hdGNoIHRoZSBob3N0Cj4ga2VybmVsIG9uIEFSTTY0CgpQ ZXJmb3JtYW5jZSBJIGNhbiB1bmRlcnN0YW5kLCBidXQgSSB0aGluayB5b3UncmUgYWxzbyB1c2lu ZyBpdCB0byBtYXNrCmEgZHJpdmVyIGJ1ZyB3aGljaCBzaG91bGQgYmUgcmVzb2x2ZWQgZmlyc3Qu ICBUaGFua3MsCgpBbGV4CgpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fXwprdm1hcm0gbWFpbGluZyBsaXN0Cmt2bWFybUBsaXN0cy5jcy5jb2x1bWJpYS5lZHUK aHR0cHM6Ly9saXN0cy5jcy5jb2x1bWJpYS5lZHUvbWFpbG1hbi9saXN0aW5mby9rdm1hcm0K 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=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 93A6AC433B4 for ; Thu, 29 Apr 2021 20:02:36 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 167E0613E1 for ; Thu, 29 Apr 2021 20:02:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 167E0613E1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=fpLb/ptavZVi1nvbkQm/h661lyecS5ARg8ZJX5aHDTg=; b=EeYrHaD7B+NRiHvxha7q7pmnA dEAQwY0kGJKXWrDicKSna/2euJsvYKOZhvCvnyGIuVSLWwqmGZKZ6b5Gg+HON0gjILwsdPIq/Mk+n T+KqqGgjBQCMmPr5xQpsBSqtKNXGUKm60UbL6wuIqtRUNdrja4Apj87/160A0Qvb+4CwNAB6jPjus JQyA2Lll6H3nJRGgSjmev/XH2XjMldY7TbnmBEWXOUihJX506i397ERReLxT8zZErF17ha+LmsCVw CxJGdkFO/b/wmrGX/q072jb5+dN3RT7Hys5VmNqIY7mLXUJ4Gl9yZwoGQAQRFuevONIrR5T37Evpp d1lu2Jg6w==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lcCq1-006MFJ-2X; Thu, 29 Apr 2021 20:00:41 +0000 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lcCd0-006KXl-5l for linux-arm-kernel@desiato.infradead.org; Thu, 29 Apr 2021 19:47:14 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-ID:Subject:Cc:To: From:Date:Sender:Reply-To:Content-ID:Content-Description; bh=+M4to1dcOs700isxx4oGCjHBz32mVchtGZDofF69pWA=; b=M1hkjxLoujiemXycktZKL4G4cu HPcL0tr2jd1Z8+pqv5P2cKZGzBklOCNBHjctJUZdJytvmsGSUYZ2LZt+IQrv//EcDxq8d1TwBYPgk 7DvPueXIVcWLl7f8YDzTiXsfVSJL4aQtEjwbRngFd6ND8xEnkv6CS9SYjjmVDl60aZg3yvdNqqajc iaTN/QdE+9jBP7U3kztCoGOzQb8x/x8NkJVo31giEQsTWwjYr2kA+6ZcH0ChDecrtmWx+ApLUS4z2 X9EfoV8QDHmTjf85u53XEOAMBFXzdC0BG8iplmmSvWjbK4q+jSNflzCIJX0qCiNmCl2e/uw9ZE/Ml Sz+LbhJQ==; Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lcCcx-000uua-CO for linux-arm-kernel@lists.infradead.org; Thu, 29 Apr 2021 19:47:12 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619725629; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+M4to1dcOs700isxx4oGCjHBz32mVchtGZDofF69pWA=; b=OVpFVCfri1gk3LLJ2mNIW7M5jv/n5AM+DXBF5DO3457+spy4TNXT4vdC3tG0eExinkCamx 9knIKR64U7TKa24djGNkD+GW8r/+i1aJRsy0ueea6/+P7oSDTfemMW5TJ5cjkwSO+9b//e oO2weDWiAmWWSNGP/Yubs1HbFJIA0VY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-79-KamNEiW9NsGsTkhGWHaQ0w-1; Thu, 29 Apr 2021 15:47:02 -0400 X-MC-Unique: KamNEiW9NsGsTkhGWHaQ0w-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9E7048189C6; Thu, 29 Apr 2021 19:47:00 +0000 (UTC) Received: from redhat.com (ovpn-113-225.phx2.redhat.com [10.3.113.225]) by smtp.corp.redhat.com (Postfix) with ESMTP id C2AFF69513; Thu, 29 Apr 2021 19:46:59 +0000 (UTC) Date: Thu, 29 Apr 2021 13:46:59 -0600 From: Alex Williamson To: Shanker R Donthineni Cc: Marc Zyngier , Will Deacon , "Catalin Marinas" , Christoffer Dall , , , , , Vikram Sethi , Jason Sequeira Subject: Re: [RFC 1/2] vfio/pci: keep the prefetchable attribute of a BAR region in VMA Message-ID: <20210429134659.321a5c3c@redhat.com> In-Reply-To: <470360a7-0242-9ae5-816f-13608f957bf6@nvidia.com> References: <20210429162906.32742-1-sdonthineni@nvidia.com> <20210429162906.32742-2-sdonthineni@nvidia.com> <20210429122840.4f98f78e@redhat.com> <470360a7-0242-9ae5-816f-13608f957bf6@nvidia.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210429_124711_520929_C695D124 X-CRM114-Status: GOOD ( 31.28 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org T24gVGh1LCAyOSBBcHIgMjAyMSAxNDoxNDo1MCAtMDUwMApTaGFua2VyIFIgRG9udGhpbmVuaSA8 c2RvbnRoaW5lbmlAbnZpZGlhLmNvbT4gd3JvdGU6Cgo+IFRoYW5rcyBBbGV4IGZvciBxdWljayBy ZXBseS4KPiAKPiBPbiA0LzI5LzIxIDE6MjggUE0sIEFsZXggV2lsbGlhbXNvbiB3cm90ZToKPiA+ IElmIHRoaXMgd2VyZSBhIHZhbGlkIHRoaW5nIHRvIGRvLCBpdCBzaG91bGQgYmUgZG9uZSBmb3Ig YWxsCj4gPiBhcmNoaXRlY3R1cmVzLCBub3QganVzdCBBUk02NC4gIEhvd2V2ZXIsIGEgcHJlZmV0 Y2hhYmxlIHJhbmdlIG9ubHkKPiA+IG5lY2Vzc2FyaWx5IGFsbG93cyBtZXJnZWQgd3JpdGVzLCB3 aGljaCBzZWVtcyBsaWtlIGEgc3Vic2V0IG9mIHRoZQo+ID4gc2VtYW50aWNzIGltcGxpZWQgYnkg YSBXQyBhdHRyaWJ1dGUsIHRoZXJlZm9yZSB0aGlzIGRvZXNuJ3Qgc2VlbQo+ID4gdW5pdmVyc2Fs bHkgdmFsaWQuCj4gPgo+ID4gSSdtIGFsc28gYSBiaXQgY29uZnVzZWQgYnkgeW91ciBwcm9ibGVt IHN0YXRlbWVudCB0aGF0IGluZGljYXRlcyB0aGF0Cj4gPiB3aXRob3V0IFdDIHlvdSdyZSBzZWVp bmcgdW5hbGlnbmVkIGFjY2Vzc2VzLCBkb2VzIHRoaXMgc3VnZ2VzdCB0aGF0Cj4gPiB5b3VyIGRy aXZlciBpcyBhY3R1YWxseSByZWx5aW5nIG9uIFdDIHNlbWFudGljcyB0byBwZXJmb3JtIG1lcmdp bmcgdG8KPiA+IGFjaGlldmUgYWxpZ25tZW50PyAgVGhhdCBzZWVtcyByYXRoZXIgbGlrZSBhIGRy aXZlciBidWcsIEknZCBleHBlY3QgVUMKPiA+IHZzIFdDIGlzIGxhcmdlbHkgYSBkaWZmZXJlbmNl IGluIHBlcmZvcm1hbmNlLCBub3QgYSBtZWFucyB0byBlbmZvcmNlCj4gPiBwcm9wZXIgZHJpdmVy IGFjY2VzcyBwYXR0ZXJucy4gIFBlciB0aGUgUENJIHNwZWMsIHRoZSBicmlkZ2UgaXRzZWxmIGNh bgo+ID4gbWVyZ2Ugd3JpdGVzIHRvIHByZWZldGNoYWJsZSBhcmVhcywgcHJlc3VtYWJseSByZWdh cmRsZXNzIG9mIHRoaXMKPiA+IHByb2Nlc3NvciBhdHRyaWJ1dGUsIHBlcmhhcHMgdGhhdCdzIHRo ZSBmZWF0dXJlIHlvdXIgZHJpdmVyIGlzIHJlbHlpbmcKPiA+IG9uIHRoYXQgbWlnaHQgYmUgbWlz c2luZyBoZXJlLiAgVGhhbmtzLCAgCj4gVGhlIGRyaXZlciB1c2VzIFdDIHNlbWFudGljcywgSXQn cyBtYXBwaW5nIFBDSSBwcmVmZXRjaGFibGUgQkFSUwo+IHVzaW5nIGlvcmVtYXBfd2MoKS7CoCBX ZSBkb24ndCBzZWUgYW55IGlzc3VlIGZvciB4ODYgYXJjaGl0ZWN0dXJlLAo+IGRyaXZlciB3b3Jr cyBmaW5lIGluIHRoZSBob3N0IGFuZCBndWVzdCBrZXJuZWwuIFRoZSBzYW1lIGRyaXZlciB3b3Jr cwo+IG9uIEFSTTY0IGtlcm5lbCBidXQgY3Jhc2hlcyBpbnNpZGUgVk0uIEdQVSBkcml2ZXIgdXNl cyB0aGUKPiBhcmNoaXRlY3R1cmUgYWdub3N0aWMgZnVuY3Rpb24gaW9yZW1hcF93YygpIGxpa2Ug b3RoZXIgZHJpdmVycy4gVGhpcwo+IGxpbWl0YXRpb24gYXBwbGllcyB0byBhbGwgdGhlIGRyaXZl cnMgaWYgdGhleSB1c2UgV0MgbWVtb3J5IGFuZAo+IGZvbGxvdyBBUk02NCBOT1JNQUwtTkMgYWNj ZXNzIHJ1bGVzLgoKeDg2IEtWTSB3b3JrcyBmb3Igb3RoZXIgcmVhc29ucywgS1ZNIHdpbGwgdHJ1 c3QgdGhlIHZDUFUgYXR0cmlidXRlcyBmb3IKdGhlIG1lbW9yeSByYW5nZSByYXRoZXIgdGhhbiBy ZWx5aW5nIG9ubHkgb24gdGhlIGhvc3QgbWFwcGluZy4KCj4gT24gQVJNNjQsIGlvcmVtYXBfd2Mo KSBpcyBtYXBwZWQgdG8gbm9uLWNhY2hlYWJsZSBtZW1vcnktdHlwZSwgbm8KPiBzaWRlIGVmZmVj dHMgb24gcmVhZHMgYW5kIHVuYWxpZ25lZCBhY2Nlc3NlcyBhcmUgYWxsb3dlZCBhcyBwZXIKPiBB Uk0tQVJNIGFyY2hpdGVjdHVyZS4gVGhlIGRyaXZlciBiZWhhdmlvciBpcyBkaWZmZXJlbnQgaW4g aG9zdCB2cwo+IGd1ZXN0IG9uIEFSTTY0LsKgCgpQZXIgdGhlIFBDSSBzcGVjLCBwcmVmZXRjaGFi bGUgbWVtb3J5IG9ubHkgbmVjZXNzYXJpbHkgYWxsb3dzIHRoZSBicmlkZ2UKdG8gbWVyZ2Ugd3Jp dGVzLiAgSSBiZWxpZXZlIHRoaXMgaXMgb25seSBhIHN1YnNldCBvZiB3aGF0IFdDIG1hcHBpbmdz CmFsbG93LCB0aGVyZWZvcmUgSSBleHBlY3QgdGhpcyBpcyBpbmNvbXBhdGlibGUgd2l0aCBkcml2 ZXJzIHRoYXQgZG8gbm90CnVzZSBXQyBtYXBwaW5ncy4KIAo+IEFSTSBDUFUgZ2VuZXJhdGluZyBh bGlnbm1lbnQgZmF1bHRzIGJlZm9yZSB0cmFuc2FjdGlvbiByZWFjaGVzIHRoZQo+IFBDSS1SQy9z d2l0Y2gvZW5kLXBvaW50LWRldmljZS4KCklmIGFuIGFsaWdubWVudCBmYXVsdCBpcyBmaXhlZCBi eSBjb25maWd1cmluZyBhIFdDIG1hcHBpbmcsIGRvZXNuJ3QKdGhhdCBzdWdnZXN0IHRoYXQgdGhl IGRyaXZlciBwZXJmb3JtZWQgYW4gdW5hbGlnbmVkIGFjY2VzcyBpdHNlbGYgYW5kCmlzIHJlbHlp bmcgb24gd3JpdGUgY29tYmluaW5nIGJ5IHRoZSBwcm9jZXNzb3IgdG8gY29ycmVjdCB0aGF0IGVy cm9yPwpUaGF0J3Mgd3JvbmcuICBGaXggdGhlIGRyaXZlciBvciBwbGVhc2Ugb2ZmZXIgYW5vdGhl ciBleHBsYW5hdGlvbiBvZgpob3cgdGhlIFdDIG1hcHBpbmcgcmVzb2x2ZXMgdGhpcy4gIEkgc3Vz cGVjdCB5b3UgY291bGQgZW5hYmxlIHRyYWNpbmcKaW4gUUVNVSwgZGlzYWJsZSBNTUlPIG1tYXBz IG9uIHRoZSB2ZmlvLXBjaSBkZXZpY2UgYW5kIGZpbmQgdGhlIGludmFsaWQKYWNjZXNzLgoKPiBX ZSd2ZSB0d28gY29uY2VybnMgaGVyZToKPiDCoMKgIC0gUGVyZm9ybWFuY2UgaW1wYWN0cyBmb3Ig cGFzcy10aHJvdWdoIGRldmljZXMuCj4gwqDCoCAtIFRoZSBkZWZpbml0aW9uIG9mIGlvcmVtYXBf d2MoKSBmdW5jdGlvbiBkb2Vzbid0IG1hdGNoIHRoZSBob3N0Cj4ga2VybmVsIG9uIEFSTTY0CgpQ ZXJmb3JtYW5jZSBJIGNhbiB1bmRlcnN0YW5kLCBidXQgSSB0aGluayB5b3UncmUgYWxzbyB1c2lu ZyBpdCB0byBtYXNrCmEgZHJpdmVyIGJ1ZyB3aGljaCBzaG91bGQgYmUgcmVzb2x2ZWQgZmlyc3Qu ICBUaGFua3MsCgpBbGV4CgoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX18KbGludXgtYXJtLWtlcm5lbCBtYWlsaW5nIGxpc3QKbGludXgtYXJtLWtlcm5lbEBs aXN0cy5pbmZyYWRlYWQub3JnCmh0dHA6Ly9saXN0cy5pbmZyYWRlYWQub3JnL21haWxtYW4vbGlz dGluZm8vbGludXgtYXJtLWtlcm5lbAo= 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=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 9F2EDC433B4 for ; Thu, 29 Apr 2021 19:47:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7ADFE613B1 for ; Thu, 29 Apr 2021 19:47:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234155AbhD2TsN (ORCPT ); Thu, 29 Apr 2021 15:48:13 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:35122 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234113AbhD2TsL (ORCPT ); Thu, 29 Apr 2021 15:48:11 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619725643; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+M4to1dcOs700isxx4oGCjHBz32mVchtGZDofF69pWA=; b=GCaohZ0xibePeliaUTQfHi46ufhAlbmYkz87Ln3FhwAtMPy9natGkRhHmHBNwjGRxIaByy 71KdGSYVMDzu6NO9Af9kKmqu5XqFEocZsrqCGA/qDZwa0FOoRzAuIowSVdYn9GJmUKaJo6 IL3XWW8fvtF3XtbcAprHsjjR4Eyv4bg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-79-KamNEiW9NsGsTkhGWHaQ0w-1; Thu, 29 Apr 2021 15:47:02 -0400 X-MC-Unique: KamNEiW9NsGsTkhGWHaQ0w-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9E7048189C6; Thu, 29 Apr 2021 19:47:00 +0000 (UTC) Received: from redhat.com (ovpn-113-225.phx2.redhat.com [10.3.113.225]) by smtp.corp.redhat.com (Postfix) with ESMTP id C2AFF69513; Thu, 29 Apr 2021 19:46:59 +0000 (UTC) Date: Thu, 29 Apr 2021 13:46:59 -0600 From: Alex Williamson To: Shanker R Donthineni Cc: Marc Zyngier , Will Deacon , "Catalin Marinas" , Christoffer Dall , , , , , Vikram Sethi , Jason Sequeira Subject: Re: [RFC 1/2] vfio/pci: keep the prefetchable attribute of a BAR region in VMA Message-ID: <20210429134659.321a5c3c@redhat.com> In-Reply-To: <470360a7-0242-9ae5-816f-13608f957bf6@nvidia.com> References: <20210429162906.32742-1-sdonthineni@nvidia.com> <20210429162906.32742-2-sdonthineni@nvidia.com> <20210429122840.4f98f78e@redhat.com> <470360a7-0242-9ae5-816f-13608f957bf6@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Thu, 29 Apr 2021 14:14:50 -0500 Shanker R Donthineni wrote: > Thanks Alex for quick reply. >=20 > On 4/29/21 1:28 PM, Alex Williamson wrote: > > If this were a valid thing to do, it should be done for all > > architectures, not just ARM64. However, a prefetchable range only > > necessarily allows merged writes, which seems like a subset of the > > semantics implied by a WC attribute, therefore this doesn't seem > > universally valid. > > > > I'm also a bit confused by your problem statement that indicates that > > without WC you're seeing unaligned accesses, does this suggest that > > your driver is actually relying on WC semantics to perform merging to > > achieve alignment? That seems rather like a driver bug, I'd expect UC > > vs WC is largely a difference in performance, not a means to enforce > > proper driver access patterns. Per the PCI spec, the bridge itself can > > merge writes to prefetchable areas, presumably regardless of this > > processor attribute, perhaps that's the feature your driver is relying > > on that might be missing here. Thanks, =20 > The driver uses WC semantics, It's mapping PCI prefetchable BARS > using ioremap_wc().=C2=A0 We don't see any issue for x86 architecture, > driver works fine in the host and guest kernel. The same driver works > on ARM64 kernel but crashes inside VM. GPU driver uses the > architecture agnostic function ioremap_wc() like other drivers. This > limitation applies to all the drivers if they use WC memory and > follow ARM64 NORMAL-NC access rules. x86 KVM works for other reasons, KVM will trust the vCPU attributes for the memory range rather than relying only on the host mapping. > On ARM64, ioremap_wc() is mapped to non-cacheable memory-type, no > side effects on reads and unaligned accesses are allowed as per > ARM-ARM architecture. The driver behavior is different in host vs > guest on ARM64.=C2=A0 Per the PCI spec, prefetchable memory only necessarily allows the bridge to merge writes. I believe this is only a subset of what WC mappings allow, therefore I expect this is incompatible with drivers that do not use WC mappings. =20 > ARM CPU generating alignment faults before transaction reaches the > PCI-RC/switch/end-point-device. If an alignment fault is fixed by configuring a WC mapping, doesn't that suggest that the driver performed an unaligned access itself and is relying on write combining by the processor to correct that error? That's wrong. Fix the driver or please offer another explanation of how the WC mapping resolves this. I suspect you could enable tracing in QEMU, disable MMIO mmaps on the vfio-pci device and find the invalid access. > We've two concerns here: > =C2=A0=C2=A0 - Performance impacts for pass-through devices. > =C2=A0=C2=A0 - The definition of ioremap_wc() function doesn't match the = host > kernel on ARM64 Performance I can understand, but I think you're also using it to mask a driver bug which should be resolved first. Thanks, Alex