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Date: Fri, 11 Nov 2011 18:38:52 +0100
From: Alexander Graf <agraf@suse.de>
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Subject: Re: [Qemu-devel] [PATCH] s390x: initialize virtio dev region
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: qemu-devel@nongnu.org

On 11/11/2011 05:44 PM, Peter Maydell wrote:
> On 11 November 2011 16:24, Alexander Graf<agraf@suse.de>  wrote:
>> On 11/11/2011 05:11 PM, Peter Maydell wrote:
>>> Yes, so that's option (2) and you need to be using a target_phys_addr_t.
>> But ram_size is ram_addr_t and is the ram size that I have available to use,
>> so it's exactly the address that I want. I don't see your point. Should go
>> jump through random useless hoops of doing
>>
>>   target_phys_addr_t ram_end = ram_size;
>>
>> just because there are some subtile semantic differences between the two
>> variables? They're integers at the end of the day. Both of them.
> Because handing a ram_addr_t to something that wants a target_phys_addr_t
> is a red flag that something might be wrong. (As is handing a variable
> called _size to something that wants an address.)
>
> Force in Newtons and Force in pound-feet are also both just integers
> at the end of the day, but that doesn't make them interchangeable:
> http://en.wikipedia.org/wiki/Mars_Climate_Orbiter#Communications_loss

How about this patch on top?

Alex


diff --git a/hw/s390-virtio.c b/hw/s390-virtio.c
index d936809..ad37a9d 100644
--- a/hw/s390-virtio.c
+++ b/hw/s390-virtio.c
@@ -188,7 +188,8 @@ static void s390_init(ram_addr_t my_ram_size,

      /* clear virtio region */
      virtio_region_len = my_ram_size - ram_size;
-    virtio_region = cpu_physical_memory_map(ram_size, 
&virtio_region_len, true);
+    virtio_region = cpu_physical_memory_map((target_phys_addr_t)ram_size,
+ &virtio_region_len, true);
      memset(virtio_region, 0, virtio_region_len);
      cpu_physical_memory_unmap(virtio_region, virtio_region_len, 1,
                                virtio_region_len);