From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1Uqs0T-0000HG-MW for mharc-qemu-trivial@gnu.org; Sun, 23 Jun 2013 17:39:33 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37411) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Uqs0R-0000EK-SZ for qemu-trivial@nongnu.org; Sun, 23 Jun 2013 17:39:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Uqs0Q-0005Gk-W3 for qemu-trivial@nongnu.org; Sun, 23 Jun 2013 17:39:31 -0400 Received: from gate.crashing.org ([63.228.1.57]:48937) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Uqs0O-0005GM-U2; Sun, 23 Jun 2013 17:39:29 -0400 Received: from [127.0.0.1] (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.13.8) with ESMTP id r5NLdIES014328; Sun, 23 Jun 2013 16:39:19 -0500 Message-ID: <1372023554.3944.111.camel@pasglop> From: Benjamin Herrenschmidt To: Anthony Liguori Date: Mon, 24 Jun 2013 07:39:14 +1000 In-Reply-To: References: <1371737338-25148-1-git-send-email-aik@ozlabs.ru> <874ncshh67.fsf@codemonkey.ws> <51C39578.6020204@ozlabs.ru> <20130623140736.GB20842@redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.4-0ubuntu1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 63.228.1.57 Cc: Anthony Liguori , "Michael S. Tsirkin" , qemu-trivial@nongnu.org, qemu-devel , Alex Williamson , qemu-ppc@nongnu.org, Paolo Bonzini , Paul Mackerras , David Gibson Subject: Re: [Qemu-trivial] [Qemu-ppc] [Qemu-devel] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support X-BeenThere: qemu-trivial@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 23 Jun 2013 21:39:32 -0000 On Sun, 2013-06-23 at 10:02 -0500, Anthony Liguori wrote: > It doesn't make a lot of sense to have Power do MSI decoding in > userspace while x86 does it in the kernel. I assume the kernel > doesn't have enough information to do the translation on Power? Well, it would need the host bridge which it doesn't have and it would need a concept of mapping that to interrupt numbers which we don't want in the kernel. We can keep the kernel side a LOT simpler (completely avoiding the whole route bloatware) by sticking to our "simple" direct map kernel stuff and doing the mapping from address/data to interrupts in qemu, so we'll stick to that. Cheers, Ben. From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37427) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Uqs0T-0000HZ-Po for qemu-devel@nongnu.org; Sun, 23 Jun 2013 17:39:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Uqs0S-0005H7-Oi for qemu-devel@nongnu.org; Sun, 23 Jun 2013 17:39:33 -0400 Message-ID: <1372023554.3944.111.camel@pasglop> From: Benjamin Herrenschmidt Date: Mon, 24 Jun 2013 07:39:14 +1000 In-Reply-To: References: <1371737338-25148-1-git-send-email-aik@ozlabs.ru> <874ncshh67.fsf@codemonkey.ws> <51C39578.6020204@ozlabs.ru> <20130623140736.GB20842@redhat.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Qemu-ppc] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Anthony Liguori , "Michael S. Tsirkin" , qemu-trivial@nongnu.org, qemu-devel , Alex Williamson , qemu-ppc@nongnu.org, Paolo Bonzini , Paul Mackerras , David Gibson On Sun, 2013-06-23 at 10:02 -0500, Anthony Liguori wrote: > It doesn't make a lot of sense to have Power do MSI decoding in > userspace while x86 does it in the kernel. I assume the kernel > doesn't have enough information to do the translation on Power? Well, it would need the host bridge which it doesn't have and it would need a concept of mapping that to interrupt numbers which we don't want in the kernel. We can keep the kernel side a LOT simpler (completely avoiding the whole route bloatware) by sticking to our "simple" direct map kernel stuff and doing the mapping from address/data to interrupts in qemu, so we'll stick to that. Cheers, Ben.