Re: [Xen-devel] [PATCH v6 12/22] arm/acpi: Prepare EFI memory descriptor for Dom0

[Shannon Zhao <shannon.zhao@xxxxxxxxxx>]

On 2016年03月22日 00:51, Julien Grall wrote:
>> +        memory_map[offset].Attribute = EFI_MEMORY_WB;
>> +    }
>> +
>> +    for( i = 0; i < acpi_mem.nr_banks; i++, offset++ )
>> +    {
>> +        memory_map[offset].Type = EfiACPIReclaimMemory;
>> +        memory_map[offset].PhysicalStart = acpi_mem.bank[i].start;
>> +        memory_map[offset].NumberOfPages =
>> PFN_UP(acpi_mem.bank[i].size);
> 
> Ditto
> 
> You are also assuming that acpi_mem.bank[i].size will always be aligned
> to 4KB. If so, we may expose unwanted data to the guest.
> 
> Based on how the field is set, I would add a BUG_ON to ensure this
> condition.
UEFI spec says
"EFI memory descriptors of type EfiACPIReclaimMemory and
EfiACPIMemoryNVS must be aligned on a 4 KiB boundary and must be a
multiple of 4 KiB in size."

So I think the size is aligned to 4kb, right?

Thanks,
-- 
Shannon

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