From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39428) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YlFIr-0003fN-3O for qemu-devel@nongnu.org; Thu, 23 Apr 2015 07:28:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YlFIn-0007fS-1V for qemu-devel@nongnu.org; Thu, 23 Apr 2015 07:28:21 -0400 Received: from mail-wi0-f178.google.com ([209.85.212.178]:37762) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YlFIm-0007fM-Rd for qemu-devel@nongnu.org; Thu, 23 Apr 2015 07:28:16 -0400 Received: by widdi4 with SMTP id di4so88845936wid.0 for ; Thu, 23 Apr 2015 04:28:16 -0700 (PDT) Message-ID: <5538D6B4.4020800@linaro.org> Date: Thu, 23 Apr 2015 13:25:40 +0200 From: Eric Auger MIME-Version: 1.0 References: <1429778977-1632-1-git-send-email-eric.auger@linaro.org> <5538BBD3.9040404@redhat.com> <5538BE19.6030009@linaro.org> <5538C246.20304@redhat.com> In-Reply-To: <5538C246.20304@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit 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: Paolo Bonzini , 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 Hi Paolo, thanks for taking the time to explain. I will rewrite accordingly. Best Regards Eric On 04/23/2015 11:58 AM, Paolo Bonzini wrote: > > > 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.