Re: [ImageBuilder][PATCH] uboot-script-gen: Add support for specifying domain P2M pool size

[Oleksandr Tyshchenko <Oleksandr_Tyshchenko@xxxxxxxx>]

On 20.01.26 20:39, Halder, Ayan Kumar wrote:
> Hi Oleksandr,

Hello Ayan

> 
> On 20/01/2026 18:23, Oleksandr Tyshchenko wrote:
>> The DOMU_P2M_MEM_MB configuration option is used to specify
>> the amount of megabytes of RAM used for the domain P2M pool.
>> It allows users to manually define the memory size reserved for
>> P2M structures in non-hardware domains, overriding the default
>> value calculated by Xen.
>>
>> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> 
> Reviewed-by: Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>

thanks


> 
> with a question
> 
>> ---
>>   README.md                | 7 +++++++
>>   scripts/uboot-script-gen | 5 +++++
>>   2 files changed, 12 insertions(+)
>>
>> diff --git a/README.md b/README.md
>> index 983cbbc..c7ae98e 100644
>> --- a/README.md
>> +++ b/README.md
>> @@ -203,6 +203,13 @@ Where:
>>     NOTE that with this option, user needs to manually set 
>> xen,passthrough
>>     in xen.dtb.
>> +- DOMU_P2M_MEM_MB[number] is optional 32-bit integer specifying the 
>> amount
>> +  of megabytes of RAM used for the domain P2M pool. If not set, the 
>> default
>> +  size is calculated by Xen.
>> +  Note that the P2M pool is used to allocate pages for P2M structures 
>> for
>> +  non-hardware domains. For the hardware domain, P2M pages are allocated
>> +  directly from the heap.
>> +
>>   - DOMU_MEM[number] is the amount of memory for the VM in MB, default 
>> 512MB
>>   - DOMU_VCPUS[number] is the number of vcpus for the VM, default 1
>> diff --git a/scripts/uboot-script-gen b/scripts/uboot-script-gen
>> index d18ac55..0c86c2d 100755
>> --- a/scripts/uboot-script-gen
>> +++ b/scripts/uboot-script-gen
>> @@ -514,6 +514,11 @@ function xen_device_tree_editing()
>>               dt_set "/chosen/domU$i" "passthrough" "str" "enabled"
>>           fi
>> +        if test -n "${DOMU_P2M_MEM_MB[$i]}"
>> +        then
>> +            dt_set "/chosen/domU$i" "xen,domain-p2m-mem-mb"
> 
> Was this property recently introduced in Xen ?

No. It was introduced more than 3 years ago by the following commit 
cbea5a1149ca7fd4b7cdbfa3ec2e4f109b601ff7 “xen/arm: Allocate and free P2M 
pages from the P2M pool”.


  If so, it may be good to
> refer Xen's commit id.
> 
> - Ayan
>