Re: [Qemu-devel] [PATCH] virtio-scsi Fix some endian bugs with virtio-scsi

[Rusty Russell <rusty@rustcorp.com.au>]

David Gibson <david@gibson.dropbear.id.au> writes:

> The virtio-scsi specification does not specify the correct endianness for
> fields in the request structure.  It's therefore best to assume that it is
> "guest native" endian since that's the (stupid and poorly defined) norm in
> virtio.
>
> However, the qemu device for virtio-scsi has no byteswaps at all, and so
> will break if the guest has different endianness from the host.  This patch
> fixes it by adding tswap() calls for the sense_len and resid fields in
> the request structure.  In theory status_qualifier needs swaps as well,
> but that field is never actually touched.  The tag field is a uint64_t, but
> since its value is completely arbitrary, it might as well be uint8_t[8]
> and so it does not need swapping.
>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Paul 'Rusty' Russell <rusty@rustcorp.com.au>
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

Good catch, thanks for this David.

Cheers,
Rusty.