Hi Ard, Thanks for comment. On 2017/2/26 18:46, Ard Biesheuvel wrote: > On 25 February 2017 at 06:47, Yisheng Xie <xieyishe...@huawei.com> wrote: >> When use device tree mode, user can reserve memory by changes the dts, >> however, when boot with ACPI, user cannot reserve memory except by >> changing the ACPI table in BIOS, which is not so convenient. >> >> To make user reserve memory for some specific use more convenient, >> this patch implement the following memmap variants: >> - memmap=nn[KMG]$ss[KMG]: mark specified memory as reserved; >> - memmap=nn[KMG]@ss[KMG]: force usage of a specific region of memory; >> >> Reported-by: Bob Dong <dong...@huawei.com> >> Signed-off-by: Yisheng Xie <xieyishe...@huawei.com> > > Could you explain which problem you are solving here? ACPI implies > UEFI on arm64, and so these reservations could be made by a boot > component instead, if it requires a fixed memory reservation. If this > is a reservation for, e.g., OP-TEE, we should not rely on the command > line to communicate this information. > We just want to reserve some memory for a driver and I just not so familiar with how to reserve memory with UEFI. So doubt about whether it is suitable to reserve memory with cmdline like "memmap=xxx", which had appeared in x86 for a long time.
Thanks Yisheng Xie