From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37069) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Uqrxu-0007ll-B7 for qemu-devel@nongnu.org; Sun, 23 Jun 2013 17:36:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Uqrxt-0004b3-CU for qemu-devel@nongnu.org; Sun, 23 Jun 2013 17:36:54 -0400 Message-ID: <1372023385.3944.108.camel@pasglop> From: Benjamin Herrenschmidt Date: Mon, 24 Jun 2013 07:36:25 +1000 In-Reply-To: <20130623140736.GB20842@redhat.com> 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] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Anthony Liguori , Alexey Kardashevskiy , qemu-devel@nongnu.org, Alexander Graf , qemu-trivial@nongnu.org, Alex Williamson , qemu-ppc@nongnu.org, Paolo Bonzini , Paul Mackerras , David Gibson On Sun, 2013-06-23 at 17:07 +0300, Michael S. Tsirkin wrote: > Yes I think that's fine really. > > Basically devices all speak MSIMessage as they should - > this is what the PCI spec says. > On all normal systems guests also speak MSIMessage so > the API which uses these makes sense for kvm. > Except, ppc architecture in its wisdom decided to hide this > in firmware. QEMU does not have firmware so the translation > has to be maintained in QEMU powerpc code. It is still not enough. There is nothing that says that an MSI address/message is unique. On pseries (among others I'm sure), this is a per-host-bridge concept since the MSIs are decoded by the PHB and turned into standard fabric interrupts there. So at least the bus needs to be passed as well. Cheers, Ben.