From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH 1/2] return available ioeventfds count in kvm_has_many_ioeventfds() Date: Tue, 13 Mar 2012 12:50:58 +0100 Message-ID: <4F5F34A2.6070301@siemens.com> References: <20120313103602.8741.71939.stgit@dhcp-8-167.nay.redhat.com> <20120313104232.8741.89133.stgit@dhcp-8-167.nay.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: aliguori@us.ibm.com, stefanha@linux.vnet.ibm.com, kvm@vger.kernel.org, mtosatti@redhat.com, qemu-devel@nongnu.org, avi@redhat.com To: Amos Kong Return-path: In-Reply-To: <20120313104232.8741.89133.stgit@dhcp-8-167.nay.redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org List-Id: kvm.vger.kernel.org Please tag uq/master patches with "PATCH uq/master". On 2012-03-13 11:42, Amos Kong wrote: > Older kernels have a 6 device limit on the KVM io bus. > This patch makes kvm_has_many_ioeventfds() return available > ioeventfd count. ioeventfd will be disabled if there is > no 7 available ioeventfds. > > Signed-off-by: Amos Kong > --- > hw/virtio-pci.c | 2 +- > kvm-all.c | 9 +++------ > 2 files changed, 4 insertions(+), 7 deletions(-) > > diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c > index a0fb7c1..d63f303 100644 > --- a/hw/virtio-pci.c > +++ b/hw/virtio-pci.c > @@ -678,7 +678,7 @@ void virtio_init_pci(VirtIOPCIProxy *proxy, VirtIODevice *vdev) > pci_register_bar(&proxy->pci_dev, 0, PCI_BASE_ADDRESS_SPACE_IO, > &proxy->bar); > > - if (!kvm_has_many_ioeventfds()) { > + if (kvm_has_many_ioeventfds() != 7) { > proxy->flags &= ~VIRTIO_PCI_FLAG_USE_IOEVENTFD; > } > > diff --git a/kvm-all.c b/kvm-all.c > index 3c6b4f0..d12694b 100644 > --- a/kvm-all.c > +++ b/kvm-all.c > @@ -78,7 +78,6 @@ struct KVMState > int pit_in_kernel; > int pit_state2; > int xsave, xcrs; > - int many_ioeventfds; > int irqchip_inject_ioctl; > #ifdef KVM_CAP_IRQ_ROUTING > struct kvm_irq_routing *irq_routes; > @@ -510,8 +509,8 @@ static int kvm_check_many_ioeventfds(void) > } > } > > - /* Decide whether many devices are supported or not */ > - ret = i == ARRAY_SIZE(ioeventfds); > + /* If i equals to 7, many devices are supported */ > + ret = i; > > while (i-- > 0) { > kvm_set_ioeventfd_pio_word(ioeventfds[i], 0, i, false); > @@ -1078,8 +1077,6 @@ int kvm_init(void) > kvm_state = s; > memory_listener_register(&kvm_memory_listener, NULL); > > - s->many_ioeventfds = kvm_check_many_ioeventfds(); > - > cpu_interrupt_handler = kvm_handle_interrupt; > > return 0; > @@ -1407,7 +1404,7 @@ int kvm_has_many_ioeventfds(void) > if (!kvm_enabled()) { > return 0; > } > - return kvm_state->many_ioeventfds; > + return kvm_check_many_ioeventfds(); And why are you dropping the caching of the kvm_check_many_ioeventfds() return value? Is kvm_has_many_ioeventfds not used outside init scopes? Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux