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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF27DC433FE for ; Thu, 24 Nov 2022 13:21:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229782AbiKXNVJ (ORCPT ); Thu, 24 Nov 2022 08:21:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42260 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229535AbiKXNVH (ORCPT ); Thu, 24 Nov 2022 08:21:07 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B70AF725F3; Thu, 24 Nov 2022 05:21:06 -0800 (PST) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1669296065; 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: in-reply-to:in-reply-to:references:references; bh=RcSivvCokxNkF1QPV7TJQxglKFkFKtiHag+c/24kTJo=; b=Jsk9wMkQor96JUMQd/WDKwECmSKycWCOitLA95BFxxMZP06HaH4uZocgjqURcQ668mYfNH s8Wkmdk2bjxps0GMI4l1NL4otlLMG48KvAP1qs77Tweavg/78hXazB/djxOWvpbnTrIDUr UtIEHjnoTp949AY+wvzy3//+oAo7352W/VScAdVXcJIVfG58qH6dnPX9Onk+fg+p7dh2Mq 79oPP1wuCRmBEvBeb3zsaMnafKkaFBMoXsTnS/FM0ClsBWZT/8HCDIKFk/dMPdrd63qvac aE0SPCBgWtQl96L4SfDFwcnO86b7p37iWoylHMXVXllK26t/MV/BbYPLRr2Vzg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1669296065; 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: in-reply-to:in-reply-to:references:references; bh=RcSivvCokxNkF1QPV7TJQxglKFkFKtiHag+c/24kTJo=; b=qaa9J1jkiXljNshb+W3Dm/bLZIVPe2i9i98NrZHMyq+qtvxx61NTon850Gw4uZDP3towos byxnDgYUBjlx2XDg== To: Jason Gunthorpe Cc: "Tian, Kevin" , LKML , "x86@kernel.org" , Joerg Roedel , Will Deacon , "linux-pci@vger.kernel.org" , Bjorn Helgaas , Lorenzo Pieralisi , Marc Zyngier , Greg Kroah-Hartman , "Jiang, Dave" , Alex Williamson , "Williams, Dan J" , Logan Gunthorpe , "Raj, Ashok" , Jon Mason , Allen Hubbe Subject: Re: [patch V2 31/33] iommu/vt-d: Enable PCI/IMS In-Reply-To: References: <20221121083657.157152924@linutronix.de> <20221121091328.184455059@linutronix.de> <87ilj4d766.ffs@tglx> Date: Thu, 24 Nov 2022 14:21:04 +0100 Message-ID: <878rk0cwu7.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 24 2022 at 09:14, Jason Gunthorpe wrote: > On Thu, Nov 24, 2022 at 10:37:53AM +0100, Thomas Gleixner wrote: >> Jason said, that the envisioned Mellanox use case does not depend on the >> IOMMU because the card itself has one which takes care of the >> protections. > > Right, but that doesn't mean we need the physical iommu turned > off. Setting the mlx pci device to identity mode is usually enough to > get back to full performance. Ok. >> How are we going to resolve that dilemma? > > The outcome is we don't have a strategy right now to make IMS work in > VMs. This series is all about making it work on physical machines, > that has to be a good first step. > > I'm hoping the OCP work stream on SIOV will tackle how to fix the > interrupt problems. Some of the ideas I've seen could be formed into > something that would work in a VM. Fair enough. Let me put the limitation into effect then. Thanks, tglx