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

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Date:   Fri, 14 Jan 2022 09:20:47 -0300
From:   Martin Fernandez <martin.fernandez@...ypsium.com>
To:     Mike Rapoport <rppt@...nel.org>
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 1/14/22, Mike Rapoport <rppt@...nel.org> wrote:
> 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.
>

Ok, will do. Thanks for the feedback.