[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api |
Date: |
Thu, 21 May 2009 16:12:31 +0300 |
User-agent: |
Mutt/1.5.18 (2008-05-17) |
On Thu, May 21, 2009 at 02:09:32PM +0100, Paul Brook wrote:
> > > A tight coupling between PCI devices and the APIC is just going to cause
> > > us problems later one. I'm going to come back to the fact that these are
> > > memory writes so once we get IOMMU support they will presumably be
> > > subject to remapping by that, just like any other memory access.
> >
> > I'm not suggesting the qemu_irq will extend all the way to the apic.
> > Think of it as connecting the device core with its interrupt unit.
> >
> > > Even ignoring that, qemu_irq isn't really the right interface. A MSI is a
> > > one- off event, not a level state. OTOH stl_phys is exactly the right
> > > interface.
> >
> > The qemu_irq callback should do an stl_phys(). The device is happy
> > since it's using the same API it uses for non-MSI.
>
> MSI provides multiple edge triggered interrupts, whereas traditional mode
> provides a single level triggered interrupt. My guess is most devices will
> want to treat these differently anyway.
So, is qemu_send_msi better than qemu_set_irq.
> Either way, this is an implementation detail between pci.c and individual
> devices. It has nothing to do with the APIC.
>
> Paul
--
MST
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, (continued)
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Avi Kivity, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Paul Brook, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Michael S. Tsirkin, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Avi Kivity, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Paul Brook, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Avi Kivity, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Michael S. Tsirkin, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Paul Brook, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Avi Kivity, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Paul Brook, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Paul Brook, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Paul Brook, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Michael S. Tsirkin, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Michael S. Tsirkin, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Michael S. Tsirkin, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Paul Brook, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Avi Kivity, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Paul Brook, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Avi Kivity, 2009/05/21
- Re: [Qemu-devel] [PATCH] qemu: msi irq allocation api, Paul Brook, 2009/05/21