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Re: [Qemu-devel] [RFC PATCH] implement vmware pvscsi device
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [RFC PATCH] implement vmware pvscsi device |
Date: |
Fri, 15 Apr 2011 15:28:21 +0100 |
On Fri, Apr 15, 2011 at 3:17 PM, Paolo Bonzini <address@hidden> wrote:
> On 04/15/2011 04:01 PM, Stefan Hajnoczi wrote:
>>
>> I think SCSI brings many benefits. Guests can deal with it better
>> than these alien vdX virtio-blk devices, which makes migration easier.
>> It becomes possible to attach many disks without burning through free
>> PCI slots. We don't need to update guests to add cache control,
>> discard, and other commands because they are part of SCSI. We can
>> pass through more exotic devices. The list goes on...
>
> And we also have to reimplement all of MMC. :)
>
> A few questions:
>
> 1) Do you have anything posted for the virtio-scsi spec? I had started
> working on one, but I haven't yet made it final. It included also
> hotplug/unplug. I can send it out on Monday.
Nothing formal. I'm trying to learn SCSI as I go along:
http://git.kernel.org/?p=linux/kernel/git/nab/lio-core-2.6.git;a=blob;f=include/linux/virtio_scsi.h;hb=refs/heads/tcm_vhost
That's the interface I'm using. Requests are:
[Header][CDB][Data-out buffers*][Data-in buffers*][Footer]
The footer gets filled in with the response.
> 2) Have you thought about making scsi-disk and scsi-generic provide a
> logical unit rather than a target? Otherwise passthrough of a whole host or
> target becomes hard or messy.
I haven't been working at the QEMU SCSI bus level. I want to wire up
the Linux-iSCSI.org target stack straight to the guest. This bypasses
the QEMU SCSI and block layers completely.
I agree that the BlockDriverState in QEMU is more of a LUN than a
target and passing through multiple block devices as LUNs should be
possible. So we probably need to restructure as you suggested and/or
provide an indirection for LUN mapping.
Stefan
- [Qemu-devel] [RFC PATCH] implement vmware pvscsi device, Paolo Bonzini, 2011/04/15
- Re: [Qemu-devel] [RFC PATCH] implement vmware pvscsi device, Stefan Hajnoczi, 2011/04/15
- Re: [Qemu-devel] [RFC PATCH] implement vmware pvscsi device, Paolo Bonzini, 2011/04/15
- Re: [Qemu-devel] [RFC PATCH] implement vmware pvscsi device,
Stefan Hajnoczi <=
- Re: [Qemu-devel] [RFC PATCH] implement vmware pvscsi device, Paolo Bonzini, 2011/04/15
- Re: [Qemu-devel] [RFC PATCH] implement vmware pvscsi device, Stefan Hajnoczi, 2011/04/15
- Re: [Qemu-devel] [RFC PATCH] implement vmware pvscsi device, Paolo Bonzini, 2011/04/15
- Re: [Qemu-devel] [RFC PATCH] implement vmware pvscsi device, Hannes Reinecke, 2011/04/18
- Re: [Qemu-devel] [RFC PATCH] implement vmware pvscsi device, Stefan Hajnoczi, 2011/04/18
- Re: [Qemu-devel] [RFC PATCH] implement vmware pvscsi device, Paolo Bonzini, 2011/04/18
- Re: [Qemu-devel] [RFC PATCH] implement vmware pvscsi device, Hannes Reinecke, 2011/04/15
- Re: [Qemu-devel] [RFC PATCH] implement vmware pvscsi device, Paolo Bonzini, 2011/04/15