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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Anthony Liguori" <aliguori@us.ibm.com>,
	"QEMU Developers" <qemu-devel@nongnu.org>,
	"Andreas Färber" <afaerber@suse.de>,
	"Marcel Apfelbaum" <marcel.a@redhat.com>
Subject: Re: [Qemu-devel] [PATCH RFC 3/3] hw/pci-host: catch acesses to unassigned pci addresses
Date: Mon, 2 Sep 2013 19:17:13 +0300	[thread overview]
Message-ID: <20130902161713.GA4971@redhat.com> (raw)
In-Reply-To: <CAFEAcA-+V7VCNoXLVCMpBc3Y7TgLAkfZNdBPA55NV3ecA=-keQ@mail.gmail.com>

On Mon, Sep 02, 2013 at 05:05:10PM +0100, Peter Maydell wrote:
> On 2 September 2013 17:00, Michael S. Tsirkin <mst@redhat.com> wrote:
> > On Mon, Sep 02, 2013 at 04:53:50PM +0100, Peter Maydell wrote:
> >> at the moment what happens is that the pci controller
> >> creates the PCI memory and io memory regions (or cheats
> >> by reusing the system memory space[*]),
> 
> >> [*] I'm pretty sure this is a bug in all platforms that do it.
> 
> > Well as usual this cheat originated with PIIX.
> > AFAIK PIIX actually has a shared bus for memory and PCI
> > so this is not a bug there, I think.
> 
> It will be when you introduce this "return -1 for unassigned
> addresses", though, since you only want that to happen
> for PCI accesses, not system memory accesses, right?
> 
> thanks
> -- PMM

What happens with PIIX is that everything that is not
in system memory is PCI.
So there's no such thing as "unassigned system memory
address": all unassigned addresses are PCI addresses.

-- 
MST

  reply	other threads:[~2013-09-02 16:15 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-02 14:13 [Qemu-devel] [PATCH RFC 0/3] pci: complete master abort protocol Marcel Apfelbaum
2013-09-02 14:13 ` [Qemu-devel] [PATCH RFC 1/3] memory: allow MemoryRegion's priority field to accept negative values Marcel Apfelbaum
2013-09-02 14:38   ` Peter Maydell
2013-09-02 14:46     ` Marcel Apfelbaum
2013-09-09 12:16     ` Marcel Apfelbaum
2013-09-02 14:13 ` [Qemu-devel] [PATCH RFC 2/3] hw/pci: add MemoryRegion ops for unassigned pci addresses Marcel Apfelbaum
2013-09-02 14:42   ` Peter Maydell
2013-09-02 15:46     ` Marcel Apfelbaum
2013-09-02 14:48   ` Michael S. Tsirkin
2013-09-02 14:51     ` Marcel Apfelbaum
2013-09-02 14:13 ` [Qemu-devel] [PATCH RFC 3/3] hw/pci-host: catch acesses to " Marcel Apfelbaum
2013-09-02 14:39   ` Peter Maydell
2013-09-02 15:42     ` Marcel Apfelbaum
2013-09-02 15:48       ` Andreas Färber
2013-09-02 15:53       ` Peter Maydell
2013-09-02 15:58         ` Peter Maydell
2013-09-02 16:00         ` Michael S. Tsirkin
2013-09-02 16:05           ` Peter Maydell
2013-09-02 16:17             ` Michael S. Tsirkin [this message]
2013-09-02 16:02         ` Marcel Apfelbaum
2013-09-02 15:57       ` Michael S. Tsirkin
2013-09-02 14:30 ` [Qemu-devel] [PATCH RFC 0/3] pci: complete master abort protocol Peter Maydell
2013-09-02 14:39   ` Marcel Apfelbaum
2013-09-02 14:43     ` Peter Maydell
2013-09-02 15:49       ` Marcel Apfelbaum

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