Re: [PATCH v6 6/6] drivers/node: Show in sysfs node's crypto capabilities

Mike Rapoport
2022-02-04T04:56:35Z

On Thu, Feb 03, 2022 at 01:43:28PM -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@eclypsium.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..0d1fd86c9faf
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-devices-node
> @@ -0,0 +1,10 @@
> +What: /sys/devices/system/node/nodeX/crypto_capable
> +Date: February 2022
> +Contact: Martin Fernandez <martin.fernandez@eclypsium.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

It didn't jump at me at previous postings, but other architectures won't
necessary have EFI_MEMORY_CPU_CRYPTO marking crypto-capable memory.

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 architectures with value corresponds to EFI_MEMORY_CPU_CRYPTO.

> + system memory is capable of being protected with the
> + CPU’s memory cryptographic capabilities. It is 0
> + otherwise.
> \ No newline at end of file
> diff --git a/drivers/base/node.c b/drivers/base/node.c
> index 87acc47e8951..dabaed997ecd 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.