linux-kernel - Re: [PATCH v5 1/5] mm/memblock: Tag memblocks with crypto capabilities

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Message-ID: <YeFHcrUUopm5xrtZ@kernel.org>
Date:   Fri, 14 Jan 2022 11:50:42 +0200
From:   Mike Rapoport <rppt@...nel.org>
To:     Martin Fernandez <martin.fernandez@...ypsium.com>
Cc:     linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
        platform-driver-x86@...r.kernel.org, linux-mm@...ck.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
        dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
        ardb@...nel.org, dvhart@...radead.org, andy@...radead.org,
        gregkh@...uxfoundation.org, rafael@...nel.org,
        akpm@...ux-foundation.org, daniel.gutson@...ypsium.com,
        hughsient@...il.com, alex.bazhaniuk@...ypsium.com,
        alison.schofield@...el.com
Subject: Re: [PATCH v5 1/5] mm/memblock: Tag memblocks with crypto
 capabilities

On Thu, Jan 13, 2022 at 06:30:23PM -0300, Martin Fernandez wrote:
> Add the capability to mark regions of the memory memory_type able of
> hardware memory encryption.
> 
> Also add the capability to query if all regions of a memory node are
> able to do hardware memory encryption to call it when initializing the
> nodes.
> 
> Signed-off-by: Martin Fernandez <martin.fernandez@...ypsium.com>
> ---
>  include/linux/memblock.h |  5 ++++
>  mm/memblock.c            | 49 ++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 54 insertions(+)
> 
> diff --git a/include/linux/memblock.h b/include/linux/memblock.h
> index 9dc7cb239d21..374c03e10b2e 100644
> --- a/include/linux/memblock.h
> +++ b/include/linux/memblock.h
> @@ -41,6 +41,7 @@ extern unsigned long long max_possible_pfn;
>   * via a driver, and never indicated in the firmware-provided memory map as
>   * system RAM. This corresponds to IORESOURCE_SYSRAM_DRIVER_MANAGED in the
>   * kernel resource tree.
> + * @MEMBLOCK_CRYPTO_CAPABLE: capable of hardware encryption
>   */
>  enum memblock_flags {
>  	MEMBLOCK_NONE		= 0x0,	/* No special request */
> @@ -48,6 +49,7 @@ enum memblock_flags {
>  	MEMBLOCK_MIRROR		= 0x2,	/* mirrored region */
>  	MEMBLOCK_NOMAP		= 0x4,	/* don't add to kernel direct mapping */
>  	MEMBLOCK_DRIVER_MANAGED = 0x8,	/* always detected via a driver */
> +	MEMBLOCK_CRYPTO_CAPABLE = 0x10,  /* capable of hardware encryption */

Nit: please keep the comments aligned with TAB.

>  };
>  
>  /**
> @@ -121,6 +123,9 @@ int memblock_physmem_add(phys_addr_t base, phys_addr_t size);
>  void memblock_trim_memory(phys_addr_t align);
>  bool memblock_overlaps_region(struct memblock_type *type,
>  			      phys_addr_t base, phys_addr_t size);
> +bool memblock_node_is_crypto_capable(int nid);
> +int memblock_mark_crypto_capable(phys_addr_t base, phys_addr_t size);
> +int memblock_clear_crypto_capable(phys_addr_t base, phys_addr_t size);
>  int memblock_mark_hotplug(phys_addr_t base, phys_addr_t size);
>  int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size);
>  int memblock_mark_mirror(phys_addr_t base, phys_addr_t size);
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 1018e50566f3..61ec50647469 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -191,6 +191,27 @@ bool __init_memblock memblock_overlaps_region(struct memblock_type *type,
>  	return i < type->cnt;
>  }
>  
> +/**
> + * memblock_node_is_crypto_capable - get if whole node is capable
> + * of encryption
> + * @nid: number of node
> + *
> + * Iterate over all memory memblock_type and find if all regions under
> + * node @nid are capable of hardware encryption.

Please add Return: description, otherwise kernel-doc is unhappy

> + */
> +bool __init_memblock memblock_node_is_crypto_capable(int nid)
> +{
> +	struct memblock_region *region;
> +
> +	for_each_mem_region(region) {
> +		if ((memblock_get_region_node(region) == nid) &&
> +		    !(region->flags & MEMBLOCK_CRYPTO_CAPABLE))
> +			return false;
> +	}

As we discussed on v3, please add a printk if the same node has both
crypto-capable and not crypto-capable regions.

https://lore.kernel.org/all/Ya++1FwWzKr2wYQH@kernel.org/

> +
> +	return true;
> +}
> +
>  /**
>   * __memblock_find_range_bottom_up - find free area utility in bottom-up
>   * @start: start of candidate range
> @@ -885,6 +906,34 @@ static int __init_memblock memblock_setclr_flag(phys_addr_t base,
>  	return 0;
>  }
>  
> +/**
> + * memblock_mark_crypto_capable - Mark memory regions capable of hardware
> + * encryption with flag MEMBLOCK_CRYPTO_CAPABLE.
> + * @base: the base phys addr of the region
> + * @size: the size of the region
> + *
> + * Return: 0 on success, -errno on failure.
> + */
> +int __init_memblock memblock_mark_crypto_capable(phys_addr_t base,
> +						 phys_addr_t size)
> +{
> +	return memblock_setclr_flag(base, size, 1, MEMBLOCK_CRYPTO_CAPABLE);
> +}
> +
> +/**
> + * memblock_clear_crypto_capable - Clear flag MEMBLOCK_CRYPTO for a
> + * specified region.
> + * @base: the base phys addr of the region
> + * @size: the size of the region
> + *
> + * Return: 0 on success, -errno on failure.
> + */
> +int __init_memblock memblock_clear_crypto_capable(phys_addr_t base,
> +						  phys_addr_t size)
> +{
> +	return memblock_setclr_flag(base, size, 0, MEMBLOCK_CRYPTO_CAPABLE);
> +}
> +
>  /**
>   * memblock_mark_hotplug - Mark hotpluggable memory with flag MEMBLOCK_HOTPLUG.
>   * @base: the base phys addr of the region
> -- 
> 2.30.2
> 

-- 
Sincerely yours,
Mike.