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Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or I
From: |
Anthony Liguori |
Subject: |
Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or IRQ or GPIO |
Date: |
Thu, 07 Mar 2013 11:17:36 -0600 |
User-agent: |
Notmuch/0.13.2+93~ged93d79 (http://notmuchmail.org) Emacs/23.3.1 (x86_64-pc-linux-gnu) |
Markus Armbruster <address@hidden> writes:
> Anthony Liguori <address@hidden> writes:
>
>> Markus Armbruster <address@hidden> writes:
>>
>>> Peter Maydell <address@hidden> writes:
>>>>>> [and I don't think "this device
>>>>>> can be added via the monitor but not the command line"
>>>>>> counts as consistent or coherent...]
>>>>>
>>>>> no_user applies equally to -device and device_add.
>>>>
>>>> In the codebase as it stands, it applies only to -device.
>>>> I agree that we should be consistent here, which we could do
>>>> by applying Christian's patch or some variation to make device_add
>>>> honour no_user. (Or by removing no_user altogether :-))
>>>
>>> Actually, it appears to apply only to help now!
>>>
>>> git-bisect blames this one:
>>
>> Let's step back and try to figure out the problem we're trying to solve.
>>
>> What is -devices help trying to show? Devices that are valid to for a
>> user to pass? Hint: on a PC, the only thing that's valid to add are
>> devices that implement a certain bus type. In fact, it depends on the
>> bus model.
>>
>> So if you want to make -device help prettier, we should add a filter
>> that looks at the busses available and filters anything that isn't an
>> instance of the appropriate bus types.
>
> Necessary, but not sufficient; see the two examples I posted upstream.
> Both devices would pass a "appropriate bus is available" filter. Both
> devices cannot possibly work. One of them starts up fine (mayhem at
> guest runtime expected),
Note that what you've done with the first one is 100% representative of
real hardware. ISA bus conflicts are part of the nature of ISA and
why it was such an awful bus.
> the other makes qemu crash & burn immediately.
This is a modeling problem. It doesn't make sense for q35-pcihost
to be a PCIDevice. It's not a PCI device.
But even so, segv'ing is always a bug and we ought to prevent it from
seg faulting. no_user to hide a SEGV is just using a bandaid.
Regards,
Anthony Liguori
- Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or IRQ or GPIO, (continued)
- Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or IRQ or GPIO, Paolo Bonzini, 2013/03/04
- Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or IRQ or GPIO, Markus Armbruster, 2013/03/07
- Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or IRQ or GPIO, Peter Maydell, 2013/03/07
- Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or IRQ or GPIO, Markus Armbruster, 2013/03/07
- Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or IRQ or GPIO, Anthony Liguori, 2013/03/07
- Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or IRQ or GPIO, Peter Maydell, 2013/03/07
- Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or IRQ or GPIO, Markus Armbruster, 2013/03/07
- Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or IRQ or GPIO,
Anthony Liguori <=
- Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or IRQ or GPIO, Markus Armbruster, 2013/03/07
- Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or IRQ or GPIO, Peter Crosthwaite, 2013/03/07
- Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or IRQ or GPIO, Peter Maydell, 2013/03/07
- Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or IRQ or GPIO, Peter Crosthwaite, 2013/03/07
- Re: [Qemu-devel] [PATCH] sysbus: add no_user for devices using mmio or IRQ or GPIO, Peter Maydell, 2013/03/07