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From: Kevin Wolf <kwolf@redhat.com>
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>
Subject: [Qemu-devel] Re: megasas: Usage of is_write in megasas_map_sgl()
Date: Fri, 03 Dec 2010 11:25:03 +0100	[thread overview]
Message-ID: <4CF8C57F.7020209@redhat.com> (raw)
In-Reply-To: <1291328663.15305.105.camel@haakon2.linux-iscsi.org>

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

  reply	other threads:[~2010-12-03 10:24 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-02 22:24 [Qemu-devel] megasas: Usage of is_write in megasas_map_sgl() Nicholas A. Bellinger
2010-12-03 10:25 ` Kevin Wolf [this message]
2010-12-03 10:42   ` [Qemu-devel] " Hannes Reinecke

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