From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Mackerras Date: Tue, 05 Feb 2019 22:13:15 +0000 Subject: Re: [PATCH 00/19] KVM: PPC: Book3S HV: add XIVE native exploitation mode Message-Id: <20190205221315.GB29038@blackberry> List-Id: References: <20190107184331.8429-1-clg@kaod.org> <20190122044654.GA15124@blackberry> <2f9b4420-ef90-20b8-d31b-dc547a6aa6b4@kaod.org> <06b7c4d2-72ba-ca4f-aded-789280798136@kaod.org> <20190204053610.GK1927@umbus.fritz.box> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: =?iso-8859-1?Q?C=E9dric?= Le Goater Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, David Gibson On Tue, Feb 05, 2019 at 12:31:28PM +0100, C=E9dric Le Goater wrote: > >>> As for nesting, I suggest for the foreseeable future we stick to XICS > >>> emulation in nested guests. > >> > >> ok. so no kernel_irqchip at all. hmm.=20 >=20 > I was confused with what Paul calls 'XICS emulation'. It's not the QEMU > XICS emulated device but the XICS-over-XIVE KVM device, the KVM XICS=20 > device KVM uses when under a P9 processor.=20 Actually there are two separate implementations of XICS emulation in KVM. The first (older) one is almost entirely a software emulation but does have some cases where it accesses an underlying XICS device in order to make some things faster (IPIs and pass-through of a device interrupt to a guest). The other, newer one is the XICS-on-XIVE emulation that Ben wrote, which uses the XIVE hardware pretty heavily. My patch was about making the the older code work when there is no XICS available to the host. Paul. 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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 D9E18C282CB for ; Tue, 5 Feb 2019 22:15:29 +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 D85A720823 for ; Tue, 5 Feb 2019 22:15:28 +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="Uu0Uerb8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D85A720823 Authentication-Results: mail.kernel.org; dmarc=none (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 lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 43vJmZ4nDdzDqPD for ; Wed, 6 Feb 2019 09:15:26 +1100 (AEDT) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (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 43vJkB3x4NzDqLJ for ; Wed, 6 Feb 2019 09:13:21 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (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.b="Uu0Uerb8"; dkim-atps=neutral Received: by ozlabs.org (Postfix, from userid 1003) id 43vJk91dRXz9sDr; Wed, 6 Feb 2019 09:13:21 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ozlabs.org; s=201707; t=1549404801; bh=6Ljkwx7omDo6K1qhkcmW+pc0EbnURQhuKPCR1guwhPo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Uu0Uerb8zXXyFWvl2KCGDqUgBTK2MdCZhPA5wT2OBjQI99KxUnE2ULz5KzcwPG6qY kjR+zd1bgrJuhUjDx8eJnYjtLw8GWmPnJVhpbcmdNBqiZjzFkQshQJeNYyq4LTxSW6 W/FAQog7uoquYM8pggvI88ttU8AzBmHL/zdGZs2SkMr7H7PPbNt3O1aItqNwMmsx77 yMAP3FuZh4veUoLAw4WF/bYThg/eP7FsKB+UK6rNHsHHMFEzqwt15SKlaqGwguQ2A1 uPWo1eAhm+p3b9akzFTJMskhHskN5berz0b8nReisP8Erb0CjmgtI/23JLmHu+jTxC VrrR3RpJUMv8A== Date: Wed, 6 Feb 2019 09:13:15 +1100 From: Paul Mackerras To: =?iso-8859-1?Q?C=E9dric?= Le Goater Subject: Re: [PATCH 00/19] KVM: PPC: Book3S HV: add XIVE native exploitation mode Message-ID: <20190205221315.GB29038@blackberry> References: <20190107184331.8429-1-clg@kaod.org> <20190122044654.GA15124@blackberry> <2f9b4420-ef90-20b8-d31b-dc547a6aa6b4@kaod.org> <06b7c4d2-72ba-ca4f-aded-789280798136@kaod.org> <20190204053610.GK1927@umbus.fritz.box> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) 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@vger.kernel.org, kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, David Gibson Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, Feb 05, 2019 at 12:31:28PM +0100, Cédric Le Goater wrote: > >>> As for nesting, I suggest for the foreseeable future we stick to XICS > >>> emulation in nested guests. > >> > >> ok. so no kernel_irqchip at all. hmm. > > I was confused with what Paul calls 'XICS emulation'. It's not the QEMU > XICS emulated device but the XICS-over-XIVE KVM device, the KVM XICS > device KVM uses when under a P9 processor. Actually there are two separate implementations of XICS emulation in KVM. The first (older) one is almost entirely a software emulation but does have some cases where it accesses an underlying XICS device in order to make some things faster (IPIs and pass-through of a device interrupt to a guest). The other, newer one is the XICS-on-XIVE emulation that Ben wrote, which uses the XIVE hardware pretty heavily. My patch was about making the the older code work when there is no XICS available to the host. Paul.