From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [RFC PATCH v2 0/4] kvm: Make ioeventfd usable on s390. Date: Sun, 24 Feb 2013 11:40:53 +0200 Message-ID: <20130224094053.GB25269@redhat.com> References: <1361534989-38884-1-git-send-email-cornelia.huck@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: KVM , linux-s390 , qemu-devel To: Cornelia Huck Return-path: Received: from mx1.redhat.com ([209.132.183.28]:8026 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752435Ab3BXJkw (ORCPT ); Sun, 24 Feb 2013 04:40:52 -0500 Content-Disposition: inline In-Reply-To: <1361534989-38884-1-git-send-email-cornelia.huck@de.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: On Fri, Feb 22, 2013 at 01:09:45PM +0100, Cornelia Huck wrote: > Here's the second attempt at implementing ioeventfd for s390. > > Rather than the architecture-specific functions used in v1, we > now try to integrate with the kvm_io_device infrastructure. > Calls to diagnose 500 subcode 3 are now mapped to _write. > These devices are created on a new KVM_CSS_BUS when using a > new flag KVM_IOEVENTFD_FLAG_CSS. addr and datamatch are (ab)used > to contain the subchannel id and the virtqueue. OK so a question: qemu has: #define KVM_S390_VIRTIO_NOTIFY 0 #define KVM_S390_VIRTIO_RESET 1 #define KVM_S390_VIRTIO_SET_STATUS 2 #define KVM_S390_VIRTIO_CCW_NOTIFY 3 So this is really s390_virtio_ccw not generally css? Maybe should say so in all headers. > we want to attach other hypercalls or carry more payload. > > Another limitation is the limit of 1000 io devices per bus, which > we would hit easily with a few hundred devices, but that should > be fixable. > > v1 -> v2: > - Move irqfd initialization from a module init function to kvm_init, > eliminating the need for a second module for kvm/s390. > - Use kvm_io_device for s390 css devices. > > > Cornelia Huck (4): > KVM: Initialize irqfd from kvm_init(). > KVM: Introduce KVM_CSS_BUS. > KVM: ioeventfd for s390 css devices. > KVM: s390: Wire up ioeventfd. > > Documentation/virtual/kvm/api.txt | 7 +++++++ > arch/s390/kvm/Kconfig | 1 + > arch/s390/kvm/Makefile | 2 +- > arch/s390/kvm/diag.c | 25 +++++++++++++++++++++++++ > arch/s390/kvm/kvm-s390.c | 1 + > include/linux/kvm_host.h | 14 ++++++++++++++ > include/uapi/linux/kvm.h | 2 ++ > virt/kvm/eventfd.c | 15 ++++++++------- > virt/kvm/kvm_main.c | 6 ++++++ > 9 files changed, 65 insertions(+), 8 deletions(-) > > -- > 1.7.12.4