From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:49429)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1XQv8O-000652-RZ
	for qemu-devel@nongnu.org; Mon, 08 Sep 2014 05:21:22 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1XQv8I-0005uG-Nt
	for qemu-devel@nongnu.org; Mon, 08 Sep 2014 05:21:16 -0400
Received: from mx1.redhat.com ([209.132.183.28]:34232)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1XQv8I-0005u0-H4
	for qemu-devel@nongnu.org; Mon, 08 Sep 2014 05:21:10 -0400
Message-ID: <540D74F9.50903@redhat.com>
Date: Mon, 08 Sep 2014 11:20:57 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
MIME-Version: 1.0
References: <20140904105223.336503578@de.ibm.com> <54097287.1000006@suse.de>
	<20140905113954.GB17325@tuxmaker.boeblingen.de.ibm.com>
	<540A44F2.3040803@suse.de>
In-Reply-To: <540A44F2.3040803@suse.de>
Content-Type: text/plain; charset=iso-8859-15
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [RFC][patch 0/6] pci pass-through support for
	qemu/KVM on s390
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Alexander Graf <agraf@suse.de>, Frank Blaschka <blaschka@linux.vnet.ibm.com>
Cc: linux-s390@vger.kernel.org, frank.blaschka@de.ibm.com, kvm@vger.kernel.org, aik@ozlabs.ru, qemu-devel@nongnu.org, Alex Williamson <alex.williamson@redhat.com>

Il 06/09/2014 01:19, Alexander Graf ha scritto:
>> > 1) interpretive execution of pci load/store instruction. If we use this function
>> >    pci access does not get intercepted (no SIE exit) but is handled via microcode.
>> >    To enable this we have to disable zpci device and enable it again with information
>> >    from the SIE control block.
> Hrm. So how about you create a special vm ioctl for KVM that allows you
> to attach a VFIO device fd into the KVM VM context? Then the default
> would stay "accessible by mmap traps", but we could accelerate it with KVM.

There is already KVM_DEV_VFIO_GROUP_ADD and KVM_DEV_VFIO_GROUP_DEL.

Right now, they result in a call to kvm_arch_register_noncoherent_dma or
kvm_arch_unregister_noncoherent_dma, but you can add more hooks.

Paolo