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Date: Tue, 05 Jul 2011 15:59:57 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 5/5] megasas: LSI Megaraid SAS emulation
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To: Alexander Graf <agraf@suse.de>
Cc: kvm@vger.kernel.org, Hannes Reinecke <hare@suse.de>, Stefan Haynoczi <stefanha@linux.vnet.ibm.com>, qemu-devel@nongnu.org

On 07/05/2011 03:38 PM, Alexander Graf wrote:
>>
>> +        if (is_sgl64) {
>> +            iov_pa = ldq_phys(pa);
>> +        } else {
>> +            iov_pa = ldl_phys(pa);
> 
> These load data from memory in target endianness. Are you sure that's 
> what you want? I'd expect this to be defined as little endian 
> (especially given that ldq and ldl on the same address work).

Seems to be target endianness from the corresponding Linux code:

        if (sge_count) {
                scsi_for_each_sg(scp, os_sgl, sge_count, i) {
                        mfi_sgl->sge32[i].length = sg_dma_len(os_sgl);
                        mfi_sgl->sge32[i].phys_addr = sg_dma_address(os_sgl);
                }
        }

...

        if (sge_count) {
                scsi_for_each_sg(scp, os_sgl, sge_count, i) {
                        mfi_sgl->sge64[i].length = sg_dma_len(os_sgl);
                        mfi_sgl->sge64[i].phys_addr = sg_dma_address(os_sgl);
                }
        }

Note that this is _either_ a ldq or a ldl depending on what the driver told
the device.  It is not accessing a 64-bit value as 32-bit.

Paolo