Re: [Qemu-devel] [PATCH 0/5] SCSI passthrough cleanup

[Laurent Vivier <Laurent.Vivier@bull.net>]

Le mercredi 23 janvier 2008 à 21:52 +0100, Fabrice Bellard a écrit :
> Two questions:
> 
> - Why do you use AIO ? If the Linux sg device supports selects, then
> using the QEMU select() callback suffices.

Basically because when I want to have asynchronous I/O I use AIO...
If you explain me briefly how to use selects in Qemu I can try.

> - Why do you use a block device ?

Because to communicate with SG device we need a file descriptor, and
using current mechanism (with -drive) allows to have this file
descriptor without modifying anything else (without adding a new
parameter). Moreover, to use Qemu AIO I need a BlockDriverState (but it
related to the first question...)

I agree to change all of this if you give me tips to use selects in Qemu
and if you thing adding a new command line parameter is not an issue.

> Regards,
> 
> Fabrice.

Thank you for your comments and help,
Laurent

> Laurent Vivier wrote:
> > This series of patches makes some cleanups in SCSI passthrough and
> > add functionnalities.
> > 
> > [PATCH 1/5] reverse scsi-generic
> > 
> > Reverse previous implementation and restore block-raw-posix.c.
> > 
> > [PATCH 2/5] Move AIO
> > 
> > This patche moves raw AIO part from block-raw-posix.c to qemu-aio-raw.c.
> > 
> > [PATCH 3/5] Add block SG interface
> > 
> > This patch re-implement scsi-generic.c using a new block interface.
> > 
> > [PATCH 4/5] DVD movie support
> > 
> > This patch allows to read a protected/encrypted movie from a DVD.
> > 
> > [PATCH 5/5] SCSI device DMA split
> > 
> > This patch allows to split a READ or WRITE into several READ or WRITE.
> > 
> > Laurent
> > 
> > 
> > 
> > 
> > 
> 
> 
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