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Date: Fri, 03 Dec 2010 11:25:03 +0100
From: Kevin Wolf <kwolf@redhat.com>
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Subject: [Qemu-devel] Re: megasas: Usage of is_write in megasas_map_sgl()
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To: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: Stefan Hajnoczi <stefanha@gmail.com>, qemu-devel <qemu-devel@nongnu.org>, Gerd Hoffmann <kraxel@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Christoph Hellwig <hch@lst.de>, Hannes Reinecke <hare@suse.de>

Am 02.12.2010 23:24, schrieb Nicholas A. Bellinger:
> The usage of a inverted is_write with cpu_physical_memory_map() also
> seems to be the case in dma-helpers.c:dma_brdv_cb():
> 
> 	mem = cpu_physical_memory_map(cur_addr, &cur_len, !dbs->is_write);
>
> After changing to an inverted is_write in megasas.v3/megasas-upstream-v1
> code, this still does *not* seem to make a difference wrt to the 64-bit
> Win7 case, and the same BSOD appears..  In any event, we should verify
> this with QEMU folks in terms of what the proper usage of is_write for
> cpu_physical_memory_map().  Gerd and Kevin comments here..?

I haven't looked at the SCSI code, but the dma-helpers.c one is easy to
explain: If you read from the disk, you write to memory.

Kevin