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Re: [Qemu-devel] [PATCH 1/2] virtio-pci: reset all qbuses too when writi
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 1/2] virtio-pci: reset all qbuses too when writing to the status field |
Date: |
Thu, 13 Dec 2012 08:56:35 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 |
Il 12/12/2012 22:32, Michael S. Tsirkin ha scritto:
> > i.e. just implement a method on the bus to do the hard-reset, and let
> > generic infrastructure call it.
>
> I dislike this approach.
> A specific function call is easier to follow.
"I dislike reading documentation, so I prefer to have ugly code than
good documentation".
The right way to fix it is to document the reset semantics, and use them.
> > No, because that would also reset the virtio-pci bits (ioeventfd etc.) which
> > virtio-scsi has no business with. What I could do is to call
> > qbus_reset_all,
> > but it makes no sense to me when there is a generic solution.
> >
>
> The virtio reset just resets virtio registers and stops DMA
> and interrupts. That is all. If it's not clear from spec
> we should make it clear.
>
> The fact that virtio scsi needs to do something special
> with qdev or whatever for this to happen is it's own business.
Same for virtio-console. If you don't call qemu_chr_fe_close, the char
device layer ends up calling chr_read in virtio-console.c which
ultimately does DMA.
It's how most qdev buses work. The bus callbacks includes a
parent->child interface to submit request and a child->parent interface
to DMA. If you do not reset the children, you do not reset DMA. Period.
> E.g. -net does it differently it checks state
> before processing packets.
> Generic virtio core does not care.
Generic qdev core cares. virtio is a qdev device and it should use
services provided by the generic framework, as much as you hate it.
Paolo
- [Qemu-devel] [PATCH 0/2] virtio: reset all qbuses too when writing to the status field, Paolo Bonzini, 2012/12/12
- [Qemu-devel] [PATCH 2/2] virtio-s390: reset all qbuses too when writing to the status field, Paolo Bonzini, 2012/12/12
- [Qemu-devel] [PATCH 1/2] virtio-pci: reset all qbuses too when writing to the status field, Paolo Bonzini, 2012/12/12
- Re: [Qemu-devel] [PATCH 1/2] virtio-pci: reset all qbuses too when writing to the status field, Michael S. Tsirkin, 2012/12/12
- Re: [Qemu-devel] [PATCH 1/2] virtio-pci: reset all qbuses too when writing to the status field, Paolo Bonzini, 2012/12/12
- Re: [Qemu-devel] [PATCH 1/2] virtio-pci: reset all qbuses too when writing to the status field, Michael S. Tsirkin, 2012/12/12
- Re: [Qemu-devel] [PATCH 1/2] virtio-pci: reset all qbuses too when writing to the status field, Paolo Bonzini, 2012/12/12
- Re: [Qemu-devel] [PATCH 1/2] virtio-pci: reset all qbuses too when writing to the status field, Michael S. Tsirkin, 2012/12/12
- Re: [Qemu-devel] [PATCH 1/2] virtio-pci: reset all qbuses too when writing to the status field, Paolo Bonzini, 2012/12/12
- Re: [Qemu-devel] [PATCH 1/2] virtio-pci: reset all qbuses too when writing to the status field, Michael S. Tsirkin, 2012/12/12
- Re: [Qemu-devel] [PATCH 1/2] virtio-pci: reset all qbuses too when writing to the status field,
Paolo Bonzini <=
Re: [Qemu-devel] [PATCH 0/2] virtio: reset all qbuses too when writing to the status field, Michael S. Tsirkin, 2012/12/12
- Re: [Qemu-devel] [PATCH 0/2] virtio: reset all qbuses too when writing to the status field, Paolo Bonzini, 2012/12/12
- Re: [Qemu-devel] [PATCH 0/2] virtio: reset all qbuses too when writing to the status field, Michael S. Tsirkin, 2012/12/12
- Message not available
- Message not available
- Re: [Qemu-devel] [PATCH 0/2] virtio: reset all qbuses too when writing to the status field, Paolo Bonzini, 2012/12/13
- Re: [Qemu-devel] [PATCH 0/2] virtio: reset all qbuses too when writing to the status field, Michael S. Tsirkin, 2012/12/16
- Re: [Qemu-devel] [PATCH 0/2] virtio: reset all qbuses too when writing to the status field, Paolo Bonzini, 2012/12/16
- Re: [Qemu-devel] [PATCH 0/2] virtio: reset all qbuses too when writing to the status field, Michael S. Tsirkin, 2012/12/16
- Re: [Qemu-devel] [PATCH 0/2] virtio: reset all qbuses too when writing to the status field, Paolo Bonzini, 2012/12/17
- Re: [Qemu-devel] [PATCH 0/2] virtio: reset all qbuses too when writing to the status field, Michael S. Tsirkin, 2012/12/17
- Re: [Qemu-devel] [PATCH 0/2] virtio: reset all qbuses too when writing to the status field, Paolo Bonzini, 2012/12/17