linux-kernel - Re: [PATCH v7 8/8] drivers/node: Show in sysfs node's crypto capabilities

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Message-ID: <CAKgze5YC_7tmrJpePH_58gbNADCQYF1S-p4Fcwp_hDy7edGGiQ@mail.gmail.com>
Date:   Tue, 26 Apr 2022 10:01:39 -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, keescook@...omium.org
Subject: Re: [PATCH v7 8/8] drivers/node: Show in sysfs node's crypto capabilities

On 4/26/22, Mike Rapoport <rppt@...nel.org> wrote:
> On Mon, Apr 25, 2022 at 02:15:26PM -0300, Martin Fernandez wrote:
>> Show in each node in sysfs if its memory is able to do be encrypted by
>> the CPU, ie. if all its memory is marked with EFI_MEMORY_CPU_CRYPTO in
>> the EFI memory map.
>>
>> Signed-off-by: Martin Fernandez <martin.fernandez@...ypsium.com>
>> ---
>>  Documentation/ABI/testing/sysfs-devices-node | 10 ++++++++++
>>  drivers/base/node.c                          | 10 ++++++++++
>>  2 files changed, 20 insertions(+)
>>  create mode 100644 Documentation/ABI/testing/sysfs-devices-node
>>
>> diff --git a/Documentation/ABI/testing/sysfs-devices-node
>> b/Documentation/ABI/testing/sysfs-devices-node
>> new file mode 100644
>> index 000000000000..5fd5dc7fc2eb
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-devices-node
>> @@ -0,0 +1,10 @@
>> +What:		/sys/devices/system/node/nodeX/crypto_capable
>> +Date:		April 2022
>> +Contact:	Martin Fernandez <martin.fernandez@...ypsium.com>
>> +Users:		fwupd (https://fwupd.org)
>> +Description:
>> +		This value is 1 if all system memory in this node is
>> +		marked with EFI_MEMORY_CPU_CRYPTO, indicating that the
>> +		system memory is capable of being protected with the
>> +		CPU’s memory cryptographic capabilities. It is 0
>> +		otherwise.
>
> I understand that currently this feature is only for x86, but if non-EFI
> architectures will start using MEMBLOCK_CRYPTO_CAPABLE, the sysfs attribute
> for will be relevant form them as well.
>
> How about
> 	This value is 1 if all system memory in this node is capable of
> 	being protected with the CPU's memory cryptographic capabilities.
> 	It is 0 otherwise.
> 	On EFI systems the node will be marked with EFI_MEMORY_CPU_CRYPTO.
>

Good point. I'll change it.

>> \ No newline at end of file
>> diff --git a/drivers/base/node.c b/drivers/base/node.c
>> index ec8bb24a5a22..1df15ea03c27 100644
>> --- a/drivers/base/node.c
>> +++ b/drivers/base/node.c
>> @@ -560,11 +560,21 @@ static ssize_t node_read_distance(struct device
>> *dev,
>>  }
>>  static DEVICE_ATTR(distance, 0444, node_read_distance, NULL);
>>
>> +static ssize_t crypto_capable_show(struct device *dev,
>> +				   struct device_attribute *attr, char *buf)
>> +{
>> +	struct pglist_data *pgdat = NODE_DATA(dev->id);
>> +
>> +	return sysfs_emit(buf, "%d\n", pgdat->crypto_capable);
>> +}
>> +static DEVICE_ATTR_RO(crypto_capable);
>> +
>>  static struct attribute *node_dev_attrs[] = {
>>  	&dev_attr_meminfo.attr,
>>  	&dev_attr_numastat.attr,
>>  	&dev_attr_distance.attr,
>>  	&dev_attr_vmstat.attr,
>> +	&dev_attr_crypto_capable.attr,
>>  	NULL
>>  };
>>
>> --
>> 2.30.2
>>
>
> --
> Sincerely yours,
> Mike.
>