From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([208.118.235.92]:57598)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <mst@redhat.com>) id 1Scdl9-0005fa-4H
	for qemu-devel@nongnu.org; Thu, 07 Jun 2012 10:32:28 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <mst@redhat.com>) id 1Scdl4-0007jw-Ba
	for qemu-devel@nongnu.org; Thu, 07 Jun 2012 10:32:22 -0400
Received: from mx1.redhat.com ([209.132.183.28]:50321)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <mst@redhat.com>) id 1Scdl4-0007jj-47
	for qemu-devel@nongnu.org; Thu, 07 Jun 2012 10:32:18 -0400
Date: Thu, 7 Jun 2012 17:32:16 +0300
From: "Michael S. Tsirkin" <mst@redhat.com>
Message-ID: <20120607143216.GA12638@redhat.com>
References: <cover.1338799935.git.jan.kiszka@siemens.com>
	<ae30bba4024251d46e1d139d509c817fc4002b7e.1338799935.git.jan.kiszka@siemens.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <ae30bba4024251d46e1d139d509c817fc4002b7e.1338799935.git.jan.kiszka@siemens.com>
Subject: Re: [Qemu-devel] [PATCH 05/13] pci: Add pci_device_route_intx_to_irq
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Alex Williamson <alex.williamson@redhat.com>, qemu-devel <qemu-devel@nongnu.org>

On Mon, Jun 04, 2012 at 10:52:13AM +0200, Jan Kiszka wrote:
> @@ -1089,6 +1093,14 @@ static void pci_set_irq(void *opaque, int irq_num, int level)
>      pci_change_irq_level(pci_dev, irq_num, change);
>  }
>  
> +PCIINTxRoute pci_device_route_intx_to_irq(PCIDevice *dev, int pin)
> +{
> +    PCIBus *bus = dev->host_bus;
> +
> +    assert(bus->route_intx_to_irq);
> +    return bus->route_intx_to_irq(bus->irq_opaque, dev->host_intx_pin[pin]);
> +}
> +
>  /***********************************************************/
>  /* monitor info on PCI */
>  

Just an idea: can devices cache this result, bypassing the
intx to irq lookup on data path?

> diff --git a/hw/pci.h b/hw/pci.h
> index 5b54e2d..bbba01e 100644
> --- a/hw/pci.h
> +++ b/hw/pci.h
> @@ -141,6 +141,15 @@ enum {
>  #define PCI_DEVICE_GET_CLASS(obj) \
>       OBJECT_GET_CLASS(PCIDeviceClass, (obj), TYPE_PCI_DEVICE)
>  
> +typedef struct PCIINTxRoute {
> +    enum {
> +        PCI_INTX_ENABLED,
> +        PCI_INTX_INVERTED,
> +        PCI_INTX_DISABLED,
> +    } mode;
> +    int irq;
> +} PCIINTxRoute;

Is this INTX route or IRQ route?
Is the INTX enabled/disabled/inverted or the IRQ?

I have the impression it's the IRQ, in the apic.
PCI INTX are never inverted they are always active low.