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[Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage |
Date: |
Tue, 29 Sep 2009 16:06:02 +0200 |
User-agent: |
Mutt/1.5.19 (2009-01-05) |
On Tue, Sep 29, 2009 at 08:55:20AM -0500, Anthony Liguori wrote:
> Michael S. Tsirkin wrote:
>> On Tue, Sep 29, 2009 at 09:22:53AM +0200, Avi Kivity wrote:
>>
>>> On 09/29/2009 08:58 AM, Michael S. Tsirkin wrote:
>>>
>>>> Using bar per feature we'll quickly run out of BARs.
>>>> We already use a BAR for MSI-X - let's add
>>>> ATA identity there?
>>>>
>>> Mixing unrelated features will quickly cause confusion.
>>>
>>
>> Note if we ever switch to 64 bit BARs, we'll only have 3 of these
>> available, so the ID would be using the last free one.
>> We can just as well plan ahead for when we'll add another feature?
>>
>> I agree fixed offsets are messy though. I previously proposed storing
>> the offset to the identity data in an i/o register. This will let each
>> implementation lay out this data in an optimal manner, without
>> confusion.
>>
>
> 1) There's no need to make the identity page separate from the config
> space. The real problem is the config space is too small. We can fix
> that without making any changes to virtio-blk by putting the config
> space in a separate BAR.
I don't think it's such a good idea. We want to keep exposing most of
config space in i/o bar because of backwards compatibility. And we want
to keep datapath operations such as vq kicks, in i/o space.
> 2) Passing an ATA identity page is goofy. We should just pass the
> serial number and let Linux generate the identity page. Just because
> Linux requires this as it's user space interface, that doesn't mean that
> other guests will (like Windows). Instead of exposing an opaque blob,
> we should expose the information we need in a structured way.
>
> Regards,
>
> Anthony Liguori
- Re: [Qemu-devel] Re: [PATCH] qemu: make virtio-blk PCI compliant by default, (continued)
- Re: [Qemu-devel] Re: [PATCH] qemu: make virtio-blk PCI compliant by default, Avi Kivity, 2009/09/22
- Re: [Qemu-devel] Re: [PATCH] qemu: make virtio-blk PCI compliant by default, john cooper, 2009/09/22
- Re: [Qemu-devel] Re: [PATCH] qemu: make virtio-blk PCI compliant by default, Anthony Liguori, 2009/09/22
- Re: [Qemu-devel] Re: [PATCH] qemu: make virtio-blk PCI compliant by default, john cooper, 2009/09/23
- [Qemu-devel] [PATCH 0/2] fix virtio_blk serial pci config breakage, john cooper, 2009/09/29
- [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage, Michael S. Tsirkin, 2009/09/29
- [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage, Avi Kivity, 2009/09/29
- [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage, Michael S. Tsirkin, 2009/09/29
- [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage, Avi Kivity, 2009/09/29
- [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage, Anthony Liguori, 2009/09/29
- [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage,
Michael S. Tsirkin <=
- [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage, Anthony Liguori, 2009/09/29
- [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage, Avi Kivity, 2009/09/29
- [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage, Michael S. Tsirkin, 2009/09/29
- [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage, Anthony Liguori, 2009/09/29
- [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage, Michael S. Tsirkin, 2009/09/29
- [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage, Rusty Russell, 2009/09/29
- [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage, Anthony Liguori, 2009/09/29
- [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage, Rusty Russell, 2009/09/29
- Re: [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage, Jamie Lokier, 2009/09/29
- [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage, john cooper, 2009/09/29