ioremap failing in linux guest

ioremap failing in linux guest

[Anish Bhatt]

I'm trying to map some memory reserved with the mem= & memap = 
parameters (in guest) in a module in the guest. ioremap keeps failing 
with xend dmesg displaying this error :
/ mm.c:710:d2 Error getting mfn 20000 (pfn 2584e) from L1 entry 
0000000020000263 for dom3275/

Anyone know why this is happening, or what I'm doing wrong ?
-Anish

-- 
As long as the music's loud enough, we won't hear the world falling apart.

Re: ioremap failing in linux guest

[Keir Fraser]

On 8/10/08 00:23, "Anish Bhatt" <anish@cc.gatech.edu> wrote:

> I'm trying to map some memory reserved with the mem= & memap =
> parameters (in guest) in a module in the guest. ioremap keeps failing
> with xend dmesg displaying this error :
> / mm.c:710:d2 Error getting mfn 20000 (pfn 2584e) from L1 entry
> 0000000020000263 for dom3275/
> 
> Anyone know why this is happening, or what I'm doing wrong ?
> -Anish

ioremap() takes machine addresses when running on Xen; not pseudophysical
addresses.

 -- Keir

Re: ioremap failing in linux guest

[Anish Bhatt]

Is there an API for converting pseudophysical addresses to machine 
addresses or possibly sample code somewhere ?
-Anish

Keir Fraser wrote:
> On 8/10/08 00:23, "Anish Bhatt" <anish@cc.gatech.edu> wrote:
>
>   
>> I'm trying to map some memory reserved with the mem= & memap =
>> parameters (in guest) in a module in the guest. ioremap keeps failing
>> with xend dmesg displaying this error :
>> / mm.c:710:d2 Error getting mfn 20000 (pfn 2584e) from L1 entry
>> 0000000020000263 for dom3275/
>>
>> Anyone know why this is happening, or what I'm doing wrong ?
>> -Anish
>>     
>
> ioremap() takes machine addresses when running on Xen; not pseudophysical
> addresses.
>
>  -- Keir
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>   


-- 
As long as the music's loud enough, we won't hear the world falling apart.

Re: ioremap failing in linux guest

[Jeremy Fitzhardinge]

Anish Bhatt wrote:
> Is there an API for converting pseudophysical addresses to machine 
> addresses or possibly sample code somewhere ?

What are you trying to achieve?  ioremap is only valid to use on device 
memory anyway, so you shouldn't be in a position to use it unless you've 
already got machine addresses in hand (and they're going to be machine 
addresses with no existing pfn translation).

    J

Re: ioremap failing in linux guest

[Anish Bhatt]

The driver for the network processor that I am using does an ioremap 
call to map memory previously reserved using the mem & memap kernel 
parameters. for eg. if I reserve memory using memmap=384M$512M, it is 
calling ioremap(384,512) (with appropriate conversion to bytes) and 
later using the returned address to setup its queues.
-Anish

Jeremy Fitzhardinge wrote:
> Anish Bhatt wrote:
>> Is there an API for converting pseudophysical addresses to machine 
>> addresses or possibly sample code somewhere ?
>
> What are you trying to achieve?  ioremap is only valid to use on 
> device memory anyway, so you shouldn't be in a position to use it 
> unless you've already got machine addresses in hand (and they're going 
> to be machine addresses with no existing pfn translation).
>
>    J


-- 
As long as the music's loud enough, we won't hear the world falling apart.

Re: ioremap failing in linux guest

[Keir Fraser]

Sounds like a 'bigphysarea' kind of hack. That won't work on Xen without
modifying the driver. Quite a part from anything else the driver probably
expects the memory range to be machine contiguous, and it almost certainly
won't be.

 -- Keir

On 9/10/08 17:50, "Anish Bhatt" <anish@cc.gatech.edu> wrote:

> The driver for the network processor that I am using does an ioremap
> call to map memory previously reserved using the mem & memap kernel
> parameters. for eg. if I reserve memory using memmap=384M$512M, it is
> calling ioremap(384,512) (with appropriate conversion to bytes) and
> later using the returned address to setup its queues.
> -Anish
> 
> Jeremy Fitzhardinge wrote:
>> Anish Bhatt wrote:
>>> Is there an API for converting pseudophysical addresses to machine
>>> addresses or possibly sample code somewhere ?
>> 
>> What are you trying to achieve?  ioremap is only valid to use on
>> device memory anyway, so you shouldn't be in a position to use it
>> unless you've already got machine addresses in hand (and they're going
>> to be machine addresses with no existing pfn translation).
>> 
>>    J
>