Re: [PATCH v4 2/4] docs, xen/arm: Introduce static heap memory

[Julien Grall <julien@xxxxxxx>]

Hi Henry,

On 07/09/2022 15:35, Henry Wang wrote:
> +Static Heap Memory
> +==================
> +
> +The static heap memory refers to parts of RAM reserved in the beginning of
> +boot time for heap. The memory is reserved by configuration in the device
> +tree using physical address ranges.
> +
> +The static heap memory declared in the device tree defines the memory areas
> +that will be reserved to be used exclusively as heap.
> +
> +- For Arm32, since there are separated heaps, the static heap will be used
> +for both domheap and xenheap. The admin should make sure that the static
> +heap region should contain enough memory below 4GB to cater 32-bit DMA.
> +
> +- For Arm64, since there is a single heap, the defined static heap areas
> +shall always go to the heap allocator.
> +
> +The static heap memory is an optional feature and can be enabled by adding
> +below device tree properties in the `chosen` node.
> +
> +The dtb should have the following properties:
> +
> +- xen,static-heap
> +
> +    Property under the top-level "chosen" node. It specifies the address
> +    and size of Xen static heap memory. Note that at least a 64KB
> +    alignment is required.
> +
> +- #xen,static-heap-address-cells and #xen,static-heap-size-cells
> +
> +    Specify the number of cells used for the address and size of the
> +    "xen,static-heap" property under "chosen".
Logging here just because it is easier to keep track of open questions 
:). For the future, I would suggest to list them after --- so they don't 
get lost.
We need to agree on the naming scheme before this gets committed.

> diff --git a/xen/arch/arm/include/asm/setup.h b/xen/arch/arm/include/asm/setup.h
> index 5815ccf8c5..31610ccd65 100644
> --- a/xen/arch/arm/include/asm/setup.h
> +++ b/xen/arch/arm/include/asm/setup.h
> @@ -22,11 +22,31 @@ typedef enum {
>       BOOTMOD_UNKNOWN
>   }  bootmodule_kind;
>   
> +enum membank_type {
> +    /*
> +     * The MEMBANK_DEFAULT type refers to either reserved memory for the
> +     * device/firmware (when the bank is in 'reserved_mem') or any RAM (when
> +     * the bank is in 'mem'.
Typo: Missing ')'

This can be updated on commit if we decide to keep the current naming 
scheme.
Cheers,

--
Julien Grall