From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [PATCH 7/9] kvm tools: Use dynamic IO port allocation in virtio-console driver Date: Wed, 25 May 2011 16:42:50 +0200 Message-ID: <20110525144250.GC29179@elte.hu> References: <1306333427-26186-1-git-send-email-levinsasha928@gmail.com> <1306333427-26186-7-git-send-email-levinsasha928@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: penberg@kernel.org, john@jfloren.net, kvm@vger.kernel.org, asias.hejun@gmail.com, gorcunov@gmail.com, prasadjoshi124@gmail.com To: Sasha Levin Return-path: Received: from mx3.mail.elte.hu ([157.181.1.138]:42969 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757457Ab1EYOmy (ORCPT ); Wed, 25 May 2011 10:42:54 -0400 Content-Disposition: inline In-Reply-To: <1306333427-26186-7-git-send-email-levinsasha928@gmail.com> Sender: kvm-owner@vger.kernel.org List-ID: * Sasha Levin wrote: > void virtio_console__init(struct kvm *kvm) > { > u8 dev, line, pin; > + u16 console_base_addr; > > if (irq__register_device(VIRTIO_ID_CONSOLE, &dev, &pin, &line) < 0) > return; > > virtio_console_pci_device.irq_pin = pin; > virtio_console_pci_device.irq_line = line; > + console_base_addr = ioport__find_free_range(); > + virtio_console_pci_device.bar[0] = console_base_addr | PCI_BASE_ADDRESS_SPACE_IO; > + cdev.base_addr = console_base_addr; > pci__register(&virtio_console_pci_device, dev); > - ioport__register(IOPORT_VIRTIO_CONSOLE, &virtio_console_io_ops, IOPORT_VIRTIO_CONSOLE_SIZE); > + ioport__register(console_base_addr, &virtio_console_io_ops, IOPORT_SIZE); Why is the ioport registration done in two steps? Wouldnt a better sequence be something like: > + console_base_addr = ioport__register(&virtio_console_io_ops, IOPORT_SIZE); > > + virtio_console_pci_device.bar[0] = console_base_addr | PCI_BASE_ADDRESS_SPACE_IO; > + cdev.base_addr = console_base_addr; > pci__register(&virtio_console_pci_device, dev); I.e. first register the ioport range - this would also get a free range for you, and then register the PCI driver? Or something even more compact could be done i suspect - all of the drivers seem to be using the same registration sequence. Thanks, Ingo