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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 CAFF2C282C0 for ; Wed, 23 Jan 2019 06:47:31 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 4A5CC21726 for ; Wed, 23 Jan 2019 06:47:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4A5CC21726 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 43kwns2kYczDqLd for ; Wed, 23 Jan 2019 17:47:29 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=permerror (mailfrom) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=benh@kernel.crashing.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 43kwlw5XmxzDqHn for ; Wed, 23 Jan 2019 17:45:48 +1100 (AEDT) Received: from localhost (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id x0N6jOn9025904; Wed, 23 Jan 2019 00:45:25 -0600 Message-ID: Subject: Re: [PATCH 18/19] KVM: PPC: Book3S HV: add passthrough support From: Benjamin Herrenschmidt To: Paul Mackerras , =?ISO-8859-1?Q?C=E9dric?= Le Goater Date: Wed, 23 Jan 2019 17:45:24 +1100 In-Reply-To: <20190122052657.GG15124@blackberry> References: <20190107184331.8429-1-clg@kaod.org> <20190107191006.10648-1-clg@kaod.org> <20190107191006.10648-2-clg@kaod.org> <20190122052657.GG15124@blackberry> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.30.4 (3.30.4-1.fc29) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, David Gibson Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, 2019-01-22 at 16:26 +1100, Paul Mackerras wrote: > On Mon, Jan 07, 2019 at 08:10:05PM +0100, Cédric Le Goater wrote: > > Clear the ESB pages from the VMA of the IRQ being pass through to the > > guest and let the fault handler repopulate the VMA when the ESB pages > > are accessed for an EOI or for a trigger. > > Why do we want to do this? > > I don't see any possible advantage to removing the PTEs from the > userspace mapping. You'll need to explain further. Afaik bcs we change the mapping to point to the real HW irq ESB page instead of the "IPI" that was there at VM init time. Cedric, is that correct ? Cheers, Ben.