From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38390) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YlDu9-0003Yl-Qa for qemu-devel@nongnu.org; Thu, 23 Apr 2015 05:58:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YlDu5-0000fm-PK for qemu-devel@nongnu.org; Thu, 23 Apr 2015 05:58:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37430) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YlDu5-0000fd-Hj for qemu-devel@nongnu.org; Thu, 23 Apr 2015 05:58:41 -0400 Message-ID: <5538C246.20304@redhat.com> Date: Thu, 23 Apr 2015 11:58:30 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1429778977-1632-1-git-send-email-eric.auger@linaro.org> <5538BBD3.9040404@redhat.com> <5538BE19.6030009@linaro.org> In-Reply-To: <5538BE19.6030009@linaro.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH 0/2] irq: add get_gsi callback List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Auger , eric.auger@st.com, qemu-devel@nongnu.org, alex.williamson@redhat.com, peter.maydell@linaro.org, agraf@suse.de Cc: kvmarm@lists.cs.columbia.edu, christoffer.dall@linaro.org, patches@linaro.org On 23/04/2015 11:40, Eric Auger wrote: >> > Why can't you just use a GHashTable? > You mean implementing this hash table in the interrupt controller? No, in KVM. Basically the kvm-vgic interrupt controller registers its qemu_irqs with kvm-all.c, passing the gsi number for KVM_IRQFD along the way. Then VFIO device can pass the qemu_irq and ask for an irqfd for that qemu_irq, instead of having to know the gsi number. kvm-all.c acts as a mediator. The notifier actually is not even necessary, because we already have a very similar concept in QOM. But qdev_init_gpio_out_named always passes a dummy "notifier": void qdev_init_gpio_out_named(DeviceState *dev, qemu_irq *pins, const char *name, int n) { int i; NamedGPIOList *gpio_list = qdev_get_named_gpio_list(dev, name); char *propname = g_strdup_printf("%s[*]", name ? name : "unnamed-gpio-out"); assert(gpio_list->num_in == 0 || !name); gpio_list->num_out += n; for (i = 0; i < n; ++i) { memset(&pins[i], 0, sizeof(*pins)); object_property_add_link(OBJECT(dev), propname, TYPE_IRQ, (Object **)&pins[i], object_property_allow_set_link, OBJ_PROP_LINK_UNREF_ON_RELEASE, &error_abort); } g_free(propname); } So you need to add a method to DeviceClass, with the same prototype as object_property_allow_set_link, and set the default value to object_property_allow_set_link in device_class_init. Then qdev_init_gpio_out_named can do DeviceClass *dc = DEVICE_GET_CLASS(dev); ... object_property_add_link(OBJECT(dev), propname, TYPE_IRQ, (Object **)&pins[i], dc->gpio_set_hook, OBJ_PROP_LINK_UNREF_ON_RELEASE, &error_abort); or something like that. Alternatively, and probably better, add the argument to qdev_init_gpio_out_named; there aren't many calls. Then you can add the method only to SysbusDeviceClass rather than to all devices, and you can change sysbus_init_irq like this: void sysbus_init_irq(SysBusDevice *dev, qemu_irq *p) { SysBusDeviceClass *sdc = SYSBUS_DEVICE_GET_CLASS(dev); qdev_init_gpio_out_named(DEVICE(dev), p, SYSBUS_DEVICE_GPIO_IRQ, 1, sdc->irq_set_hook); } Paolo > The problem is my VFIO device currently has no link to the interrupt > controller object. Besides it has a platform bus in between. Previously > I devised a reset notifier called in the machine file to pass this link > but Alex was not keen about this method. So the idea here is when the > VFIO sysbus device qemuirq is getting connected, a notifier is called, > VFIO device can retrieve the gsi of this qemu_irq and call KVM_IRQFD > with that gsi.