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.