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Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive |
Date: |
Fri, 24 Aug 2012 11:14:33 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120717 Thunderbird/14.0 |
Il 24/08/2012 12:43, Hannes Reinecke ha scritto:
> Hehe. So finally someone else stumbled across this one.
>
> All is fine and dandy as long as you're able to use scsi-disk.
> As soon as you're forced to use scsi-generic we're in trouble.
>
> With scsi-generic we actually have two problems:
> 1) scsi-generic just acts as a pass-through and passes the commands
> as-is, including the scatter-gather information as formatted by
> the guest. So the guest could easily format an SG_IO comand
> which will not be compatible with the host.
> 2) The host is not able to differentiate between a malformed
> SG_IO command and a real I/O error; in both cases it'll return
> -EIO.
>
> So we can fix this by either
> a) ignore (as we do nowadays :-)
> b) Fixup scsi-generic to inspect and modify SG_IO information
> to ensure the host-limits are respected
That's what scsi-block already does.
Perhaps sooner or later we will need a scsi-tape? That would be fine.
> Yes, it's painful. But in the long run we'll have to do an SG_IO
> inspection anyway, otherwise we'll always be susceptible to malicious
> SG_IO attacks.
I would like to do this in the kernel using BPF. I posted a possible
spec at
http://www.redhat.com/archives/libvir-list/2012-June/msg00505.html but
the response was, ehm, underwhelming.
Paolo
- Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, (continued)
- Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Paolo Bonzini, 2012/08/22
- Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Cong Meng, 2012/08/23
- Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Paolo Bonzini, 2012/08/23
- Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Stefan Hajnoczi, 2012/08/23
- Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Paolo Bonzini, 2012/08/23
- Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Stefan Hajnoczi, 2012/08/23
- Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Nicholas A. Bellinger, 2012/08/23
- Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Paolo Bonzini, 2012/08/24
- Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Hannes Reinecke, 2012/08/24
- Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Stefan Hajnoczi, 2012/08/24
- Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive,
Paolo Bonzini <=
Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Stefan Hajnoczi, 2012/08/21
Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Blue Swirl, 2012/08/21