From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH V6 0/6] Fast mmio eventfd fixes Date: Tue, 10 Nov 2015 14:25:26 +0800 Message-ID: <56418DD6.4060608@redhat.com> References: <1442299319-5253-1-git-send-email-jasowang@redhat.com> <20151108191056-mutt-send-email-mst@redhat.com> <564022A1.2040003@redhat.com> <20151109221825-mutt-send-email-mst@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: gleb@kernel.org, pbonzini@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, cornelia.huck@de.ibm.com To: "Michael S. Tsirkin" Return-path: In-Reply-To: <20151109221825-mutt-send-email-mst@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 11/10/2015 04:19 AM, Michael S. Tsirkin wrote: > On Mon, Nov 09, 2015 at 12:35:45PM +0800, Jason Wang wrote: >> > >> > >> > On 11/09/2015 01:11 AM, Michael S. Tsirkin wrote: >>> > > On Tue, Sep 15, 2015 at 02:41:53PM +0800, Jason Wang wrote: >>>> > >> Hi: >>>> > >> >>>> > >> This series fixes two issues of fast mmio eventfd: >>>> > >> >>>> > >> 1) A single iodev instance were registerd on two buses: KVM_MMIO_BUS >>>> > >> and KVM_FAST_MMIO_BUS. This will cause double in >>>> > >> ioeventfd_destructor() >>>> > >> 2) A zero length iodev on KVM_MMIO_BUS will never be found but >>>> > >> kvm_io_bus_cmp(). This will lead e.g the eventfd will be trapped by >>>> > >> qemu instead of host. >>>> > >> >>>> > >> 1 is fixed by allocating two instances of iodev and introduce a new >>>> > >> capability for userspace. 2 is fixed by ignore the actual length if >>>> > >> the length of iodev is zero in kvm_io_bus_cmp(). >>>> > >> >>>> > >> Please review. >>>> > >> Changes from V5: >>>> > >> - move patch of explicitly checking for KVM_MMIO_BUS to patch 1 and >>>> > >> remove the unnecessary checks >>>> > >> - even more grammar and typo fixes >>>> > >> - rabase to kvm.git >>>> > >> - document KVM_CAP_FAST_MMIO >>> > > What's up with userspace using this capability? >> > >> > It was renamed to KVM_CAP_IOEVENTFD_ANY_LENGTH. >> > >>> > > Did patches ever get posted? >> > >> > See https://lkml.org/lkml/2015/9/28/208 > Talking about userspace here. > QEMU freeze is approaching, it really should > use this to avoid regressions. > The patches were posted at http://lists.gnu.org/archive/html/qemu-devel/2015-11/msg01276.html (you were in cc list)