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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: |
Wed, 22 Aug 2012 14:09:28 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120717 Thunderbird/14.0 |
Il 22/08/2012 13:04, Cong Meng ha scritto:
>>
>> Cong, what is the limit that the host HBA enforces (and what is the
>> HBA)? What commands see a problem? Is it fixed by using scsi-block
>> instead of scsi-generic (if you can use scsi-block at all, i.e. it's not
>> a tape or similar device)?
>>
> I don't see real problem caused by the the queue limits actually. It's a
> bug which Stefan told me.
I'd rather avoid patching the specification if not to solve real (rather
than known-but-theoretical) problems.
>> With scsi-generic, QEMU uses a bounce buffer for non-I/O commands to a
>> SCSI passthrough device, so the only problem in that case should be the
>> maximum segment size. This could change in the future, but max_segments
>> and max_sectors should not yet be a problem.
>
> about bounce buffer, do you meat the buffer allocated in
> scsi_send_command() of hw/scsi-generic.c?
Yes.
Paolo
- [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Cong Meng, 2012/08/21
- [Qemu-devel] [PATCH 2/2 v1] virtio-scsi: set per-LUN queue limits for sg devices, Cong Meng, 2012/08/21
- Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Paolo Bonzini, 2012/08/21
- Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Cong Meng, 2012/08/21
- 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, Paolo Bonzini, 2012/08/21
- Re: [Qemu-devel] [PATCH 1/2 v1] blkdrv: Add queue limits parameters for sg block drive, Cong Meng, 2012/08/22
- 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, 2012/08/22
- 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