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[Qemu-devel] Re: [PATCH] fix virtio_blk serial pci config breakage, v2
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] Re: [PATCH] fix virtio_blk serial pci config breakage, v2 |
Date: |
Wed, 7 Oct 2009 15:52:38 +0200 |
User-agent: |
Mutt/1.5.19 (2009-01-05) |
On Wed, Oct 07, 2009 at 08:48:32AM -0500, Anthony Liguori wrote:
> john cooper wrote:
>> Michael S. Tsirkin wrote:
>>
>>>> + put_le16(p + 0, 0x0); /* ATA device */
>>>> + padstr((char *)(p + 23), QEMU_VERSION, 8); /* firmware revision
>>>> */
>>>>
>>> QEMU version is currently a string like "0.11.50" which is exactly 8
>>> bytes. What if someone makes it longer? padstr will not 0
>>> terminate string, and only partial data will be there.
>>>
>>
>> This code treats the field similar to the logic from which
>> it derives (hw/ide.c) in that the field need not be nul
>> terminated. Quiet truncation to 8 bytes can occur here
>> and in the existing usage but in a practical sense I don't
>> see much of a recourse. We can flag a warning but the
>> data is realistically a best-effort attempt to provide
>> relevant information in this field. IOW overflowing
>> this field probably isn't justification alone to modify
>> a too long qemu version string.
>>
>
> Hrm, we really shouldn't be exposing a version string to the guest in
> the first place.
>
> That's a compatibility issue.
Actually, it's a good point. Otherwise e.g. the identity changes with
migration. My understanding is that this isn't the only place where
we do this?
> Really, I strongly dislike passing this identity page via virtio. Why
> are we still going this route instead of just passing the S/N?
No opinion on this.
> Regards,
>
> Anthony Liguori
- [Qemu-devel] [PATCH] fix virtio_blk serial pci config breakage, v2, john cooper, 2009/10/05
- [Qemu-devel] Re: [PATCH] fix virtio_blk serial pci config breakage, v2, Michael S. Tsirkin, 2009/10/05
- [Qemu-devel] Re: [PATCH] fix virtio_blk serial pci config breakage, v2, john cooper, 2009/10/07
- [Qemu-devel] Re: [PATCH] fix virtio_blk serial pci config breakage, v2, Anthony Liguori, 2009/10/07
- [Qemu-devel] Re: [PATCH] fix virtio_blk serial pci config breakage, v2,
Michael S. Tsirkin <=
- [Qemu-devel] Re: [PATCH] fix virtio_blk serial pci config breakage, v2, Anthony Liguori, 2009/10/07
- [Qemu-devel] Re: [PATCH] fix virtio_blk serial pci config breakage, v2, john cooper, 2009/10/07
[Qemu-devel] Re: [PATCH] fix virtio_blk serial pci config breakage, v2, Michael S. Tsirkin, 2009/10/05
[Qemu-devel] Re: [PATCH] fix virtio_blk serial pci config breakage, v2, Anthony Liguori, 2009/10/06