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=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 3751AC433E0 for ; Tue, 30 Jun 2020 02:28:52 +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 789E720702 for ; Tue, 30 Jun 2020 02:28:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=ozlabs.org header.i=@ozlabs.org header.b="HAPr1ft0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 789E720702 Authentication-Results: mail.kernel.org; dmarc=pass (p=none dis=none) header.from=ozlabs.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 49wpFY1JgMzDqgB for ; Tue, 30 Jun 2020 12:28:49 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 49wpCp53WhzDqKv for ; Tue, 30 Jun 2020 12:27:18 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=ozlabs.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=ozlabs.org header.i=@ozlabs.org header.a=rsa-sha256 header.s=201707 header.b=HAPr1ft0; dkim-atps=neutral Received: by ozlabs.org (Postfix, from userid 1003) id 49wpCp1LFCz9sRk; Tue, 30 Jun 2020 12:27:18 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ozlabs.org; s=201707; t=1593484038; bh=NFM6COCoADkJtON3c24Vv6dFmjtqhT4V6y1+lHPgb0g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HAPr1ft04WysSZiADOMjCalamrA2adoBIwdiJ0pp2KzZhZVSmLmTsuGjLjCxYggFr q8DiWs7T4bJs329eLGZx7d4U281mnCNHKeyrctNhSGtBnj0cJJj3Wz/N+aRJgkhIRu JBgeZ5EjOYIewS9wFaYJPP3pfL/Hf3OlIUuppXCgR/9evzKx+xtCIXquNUwyrChwok GH4YJkNpGXJG8FwvzktyPgLLPWFLDU/I3eNGgS0/Hy69HTMtLrxCq+wrcr4PiLe3AF GGr0iHUJyQSKRDXJtsbxCJW04BzXYtzeyv0Hdw3MeOCelCh9ZQ3eEpNYjWT7ic5gaB xPvLycUUxw1Vw== Date: Tue, 30 Jun 2020 12:27:13 +1000 From: Paul Mackerras To: Nicholas Piggin Subject: Re: [PATCH 3/3] powerpc/pseries: Add KVM guest doorbell restrictions Message-ID: <20200630022713.GA618342@thinks.paulus.ozlabs.org> References: <20200627150428.2525192-1-npiggin@gmail.com> <20200627150428.2525192-4-npiggin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200627150428.2525192-4-npiggin@gmail.com> 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: kvm-ppc@vger.kernel.org, Anton Blanchard , =?iso-8859-1?Q?C=E9dric?= Le Goater , linuxppc-dev@lists.ozlabs.org, David Gibson Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sun, Jun 28, 2020 at 01:04:28AM +1000, Nicholas Piggin wrote: > KVM guests have certain restrictions and performance quirks when > using doorbells. This patch tests for KVM environment in doorbell > setup, and optimises IPI performance: > > - PowerVM guests may now use doorbells even if they are secure. > > - KVM guests no longer use doorbells if XIVE is available. It seems, from the fact that you completely remove kvm_para_available(), that you perhaps haven't tried building with CONFIG_KVM_GUEST=y. Somewhat confusingly, that option is not used or needed when building for a PAPR guest (i.e. the "pseries" platform) but is used on non-IBM platforms using the "epapr" hypervisor interface. If you did intend to remove support for the epapr hypervisor interface then that should have been talked about in the commit message (and would I expect be controversial). So NAK on the kvm_para_available() removal. Paul.