Re: [Xen-devel] [PATCH v5 6/9] libxc: create unmapped initrd in domain builder if supported

[Juergen Gross <jgross@xxxxxxxx>]

On 30/11/15 11:20, Wei Liu wrote:
> On Thu, Nov 26, 2015 at 08:35:02AM +0100, Juergen Gross wrote:
>> On 25/11/15 17:12, Boris Ostrovsky wrote:
>>> On 11/12/2015 08:43 AM, Juergen Gross wrote:
>>>> In case the kernel of a new pv-domU indicates it is supporting an
>>>> unmapped initrd, don't waste precious virtual space for the initrd,
>>>> but allocate only guest physical memory for it.
>>>
>>> This patch breaks 32-bit pygrub.
>>>
>>> I am not 100% sure yet but it may be that only 64-bit guests are affected.
>>>
>>> With RHEL5 I get
>>>     initrd extends beyond end of memory (0x780080eda000 > 0x40000000)
>>
>> I think I have found the problem. Can you verify the attached patch is
>> working?
>>
>>
>> Juergen
>>
> 
>> From 11eaee2aa2291a1d56556d538ac23b8156cf3388 Mon Sep 17 00:00:00 2001
>> From: Juergen Gross <jgross@xxxxxxxx>
>> Date: Thu, 26 Nov 2015 08:32:26 +0100
>> Subject: [PATCH] libxc: correct domain builder for 64 bit guest with 32 bit
>>  tools
>>
>> Commit 8c45adec18e0512c3d34dcafb13414ecba21be6a ("create unmapped
>> initrd in domain builder if supported") introduced an error for
>> building a 64 bit guest with a 32 bit toolset.
>>
>> The initrd start address and size where stored in an unsigned long
>> instead of using a 64 bit type.
>>
>> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
>> ---
>>  tools/libxc/include/xc_dom.h | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/libxc/include/xc_dom.h b/tools/libxc/include/xc_dom.h
>> index 2176216..370dddd 100644
>> --- a/tools/libxc/include/xc_dom.h
>> +++ b/tools/libxc/include/xc_dom.h
>> @@ -99,8 +99,8 @@ struct xc_dom_image {
>>      xen_vaddr_t bsd_symtab_start;
>>  
>>      /* initrd parameters as specified in start_info page */
>> -    unsigned long initrd_start;
>> -    unsigned long initrd_len;
>> +    uint64_t initrd_start;
>> +    uint64_t initrd_len;
>>  
> 
> I think these should be of type xen_vaddr_t. Doesn't make a difference
> in the end though.

xen_vaddr_t seems not to be appropriate. It can be either a virtual
address or a pfn. So the type should be agnostic to any special
semantics and just needs to be big enough for all cases.


Juergen


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