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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_PASS,URIBL_BLOCKED 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 86945C43381 for ; Mon, 18 Mar 2019 13:31:02 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 57CBF20850 for ; Mon, 18 Mar 2019 13:31:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="SCS7Ibx/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 57CBF20850 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-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=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject: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=EldapSeTzw1f19EEHBCzZ4qkfohgyzuWTUU00OnFviw=; b=SCS7Ibx/ASJYM2 NMcb8VKn8HYdrVKqKk+q9vUF0YEcgC7x5necPVNXudSrs8ZDDEf2LvANoN8BRX0hKWeSxWS77o64o 78pjN/d7N4tlSqNgvnb07BA4rWKsYoZk1k4W3cGIAss5tpVncPRkBIxCv6HuwdWcWi0dyESwyP4yJ SbArioObiMD0o9MVSCbN3EasnpZJ1Y+bLAGBgRijKZ/49GJ6K2GK6eGwLcY0rX4gXE3VBca+nj1WM cwl9JFbHHiYHZvAvXqu9EVbjiIE8FkAVauM8W7dL/XAaChRqbWBvotgOwO10E5WkMp/vfM4BRxZdq t2XieV3ouHFOvba0eKLQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h5sLt-0000SR-Ru; Mon, 18 Mar 2019 13:30:53 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h5sLr-0000S1-2x for linux-arm-kernel@lists.infradead.org; Mon, 18 Mar 2019 13:30:51 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 472CEEBD; Mon, 18 Mar 2019 06:30:50 -0700 (PDT) Received: from why.wild-wind.fr.eu.org (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EBA293F71A; Mon, 18 Mar 2019 06:30:46 -0700 (PDT) Date: Mon, 18 Mar 2019 13:30:40 +0000 From: Marc Zyngier To: Zenghui Yu Subject: Re: [RFC PATCH] KVM: arm/arm64: Enable direct irqfd MSI injection Message-ID: <20190318133040.1cfad9a4@why.wild-wind.fr.eu.org> In-Reply-To: <86o969z42z.wl-marc.zyngier@arm.com> References: <1552833373-19828-1-git-send-email-yuzenghui@huawei.com> <86o969z42z.wl-marc.zyngier@arm.com> Organization: ARM Ltd X-Mailer: Claws Mail 3.17.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190318_063051_132543_BEC6AD9A X-CRM114-Status: GOOD ( 11.86 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: rkrcmar@redhat.com, mst@redhat.com, kvm@vger.kernel.org, julien.thierry@arm.com, "Raslan, KarimAllah" , andre.przywara@arm.com, suzuki.poulose@arm.com, christoffer.dall@arm.com, linux-kernel@vger.kernel.org, eric.auger@redhat.com, james.morse@arm.com, wanghaibin.wang@huawei.com, pbonzini@redhat.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sun, 17 Mar 2019 19:35:48 +0000 Marc Zyngier wrote: [...] > A first approach would be to keep a small cache of the last few > successful translations for this ITS, cache that could be looked-up by > holding a spinlock instead. A hit in this cache could directly be > injected. Any command that invalidates or changes anything (DISCARD, > INV, INVALL, MAPC with V=0, MAPD with V=0, MOVALL, MOVI) should nuke > the cache altogether. And to explain what I meant with this, I've pushed a branch[1] with a basic prototype. It is good enough to get a VM to boot, but I wouldn't trust it for anything serious just yet. If anyone feels like giving it a go and check whether it has any benefit performance wise, please do so. Thanks, M. [1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=kvm-arm64/its-translation-cache -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel