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,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 A02F4C433E0 for ; Fri, 26 Feb 2021 21:18:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 52CEA64F0E for ; Fri, 26 Feb 2021 21:18:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231129AbhBZVSE (ORCPT ); Fri, 26 Feb 2021 16:18:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:36580 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230464AbhBZVR7 (ORCPT ); Fri, 26 Feb 2021 16:17:59 -0500 Received: by mail.kernel.org (Postfix) with ESMTPS id C24EE64F26 for ; Fri, 26 Feb 2021 21:17:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614374234; bh=6hjPDaWAzzG/U3xcNVLKJg8iviBNtdcM+5P0QYQACno=; h=From:To:Subject:Date:In-Reply-To:References:From; b=RQHLm4ehuCYIkEMFymcX11vrJXlnuecqg2pa3QaXTISpYMIf8Y63Fcfygu5u4Bqm4 Fk1JjuSjB7oDIeij/UGhhQgT65QxT+JKB4sOWRDFCclWyYs5BKYt6G/6N+OjWMGmLR rh4rbWj3Z5HI65Ln0sJjggtYr3q7EytCA2Se+oeFHbQLuZOelyIXr1mpeVR08p3yG7 JsQiTZ09pZYRj7wBtAX7OLgizTcQlZul3oZCD3e7IptluypuIJPtTbviBYjBgO0uF5 qT/FZvGqDspP0BkVh+r7WWLbjINn7dNC2N7xqMSW8JPrm3o2D1Gkaw3oKXbNViHiTb leAc2v9QowdMA== From: bugzilla-daemon@bugzilla.kernel.org To: kvm@vger.kernel.org Subject: [Bug 201753] AMD-Vi: Unable to write to IOMMU perf counter Date: Fri, 26 Feb 2021 21:17:14 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: AssignedTo virtualization_kvm@kernel-bugs.osdl.org X-Bugzilla-Product: Virtualization X-Bugzilla-Component: kvm X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: david.coe@live.co.uk X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: virtualization_kvm@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org https://bugzilla.kernel.org/show_bug.cgi?id=3D201753 --- Comment #14 from David Coe (david.coe@live.co.uk) --- Good evening, all! Two extra results from the Ryzen 2400G: 1. 5 x 25 msec loop on Ubuntu 21.04, kernel 5.10.11 and Suravee's original patch. Works fine! 2. 10x 20 msec loop on Ubuntu 20.10, kernel 5.8.18 with both Suravee and Al= ex's patches. Also fine! As expected, AMD-Vi: IOMMU performance counters supported moves to after Adding to iommu group ... This means that, for this CPU, the power-gating needs between 100 - 125 mse= c to disable. A logging printf would have got me there faster (not overly fond of kernel rebuilds) but the missing information is the maximum settling-time needed across the full Ryzen range. Paul's suggestion of increasing the loop count to 10 gives 200 msec maximum headroom. Surely must be enough? Now, all we need is a work-around for the PCI INT A: not connected diagnost= ic :-). Many thanks good people. Keep safe. David --=20 You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.=