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Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices |
Date: |
Thu, 10 Jan 2013 13:01:26 +0000 |
On 10 January 2013 12:45, Paolo Bonzini <address@hidden> wrote:
> Il 10/01/2013 13:31, Peter Maydell ha scritto:
>> On 10 January 2013 12:12, Paolo Bonzini <address@hidden> wrote:
>>> It's just an implementation detail. Right now we have a common
>>> callback. The idea is to give each bus its own callback. In the case
>>> of sysbus it would just call a method; for PCI it would reset some
>>> configuration and then call a method; for SCSI there is no need to call
>>> a method at all; and so on.
>>
>> But machine reset shouldn't call bus specific PCI or SCSI reset
>> methods -- we've just effectively yanked the power to the VM
>> so everything should just reset as if it was freshly constructed.
>
> Yes, but we do not have a way to do that, so QEMU resorts to a warm reset.
qdev reset is cold reset, not warm reset.
>> A bus-specific reset method would be for buses where the bus
>> itself has some sort of guest-triggerable reset (by prodding the
>> chipset, for instance).
>
> Yes.
>
>>> In addition, navigating the qdev tree should be explicit in the methods.
>>> It will not happen anymore via the "magic" qdev_reset_all.
>>
>> *Something* has to say "call reset for every qdev object in the
>> system", surely?
>
> It will call it on sysbus, which will call it on every sysbus child.
> Devices that have a child bus will propagate it further down.
This doesn't work when we get rid of the idea that every qdev
device is attached to a tree of buses.
(At this point in the conversation I'm pretty confused about exactly
what we're trying to do :-))
-- PMM
- Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, (continued)
- Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, Paolo Bonzini, 2013/01/09
- Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, Michael S. Tsirkin, 2013/01/09
- Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, Paolo Bonzini, 2013/01/10
- Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, Michael S. Tsirkin, 2013/01/10
Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, Peter Maydell, 2013/01/10
- Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, Paolo Bonzini, 2013/01/10
- Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, Peter Maydell, 2013/01/10
- Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, Paolo Bonzini, 2013/01/10
- Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, Peter Maydell, 2013/01/10
- Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, Paolo Bonzini, 2013/01/10
- Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices,
Peter Maydell <=
- Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, Paolo Bonzini, 2013/01/10
Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, Anthony Liguori, 2013/01/10
Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, Paolo Bonzini, 2013/01/10
Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices, Michael S. Tsirkin, 2013/01/10