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Re: [Qemu-devel] [PATCH for-2.2 v2 0/5] scsi: enable passthrough of vend
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH for-2.2 v2 0/5] scsi: enable passthrough of vendor-specific commands |
Date: |
Tue, 29 Jul 2014 15:17:35 +0800 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Mon, 07/28 17:08, Paolo Bonzini wrote:
> Right now scsi-generic is parsing the CDB, in order to compute
> the expected number of bytes to be transferred. This is necessary
> if DMA is done by the HBA via scsi_req_data, but it prevents executing
> vendor-specific commands via scsi-generic because we don't know how
> to parse them.
>
> If DMA is delegated to the SCSI layer via get_sg_list, we know in
> advance how many bytes the guest will want to receive and we can pass
> the information straight from the guest to SG_IO. In this case, it is
> unnecessary to parse the CDB to get the same information. scsi-disk needs
> it to detect underruns and overruns, but scsi-generic and scsi-block can
> just ask the HBA about the transfer direction and size.
>
> This series introduces a new parse_cdb callback in both the device and
> the HBA. The latter is called by scsi_bus_parse_cdb, which devices can
> call for passthrough requests in their implementation of parse_cdb.
>
> Paolo
>
> v1->v2: use the "right" CDB size for non-vendor-specific commands,
> as some drivers and/or firmware expect that and complain
> if you pass a READ(10) command in a 16-byte CDB. Interdiff
> here.
More learning than reviewing for me, so take this with a grain of salt:
Reviewed-by: Fam Zheng <address@hidden>
- [Qemu-devel] [PATCH for-2.2 v2 0/5] scsi: enable passthrough of vendor-specific commands, Paolo Bonzini, 2014/07/28
- [Qemu-devel] [PATCH 1/5] scsi-bus: prepare scsi_req_new for introduction of parse_cdb, Paolo Bonzini, 2014/07/28
- [Qemu-devel] [PATCH 2/5] scsi-bus: introduce parse_cdb in SCSIDeviceClass and SCSIBusInfo, Paolo Bonzini, 2014/07/28
- [Qemu-devel] [PATCH 3/5] scsi-block: extract scsi_block_is_passthrough, Paolo Bonzini, 2014/07/28
- [Qemu-devel] [PATCH 4/5] scsi-block, scsi-generic: implement parse_cdb, Paolo Bonzini, 2014/07/28
- [Qemu-devel] [PATCH 5/5] virtio-scsi: implement parse_cdb, Paolo Bonzini, 2014/07/28
- Re: [Qemu-devel] [PATCH for-2.2 v2 0/5] scsi: enable passthrough of vendor-specific commands,
Fam Zheng <=