[PATCH v4 5/5] drivers/node: Show in sysfs node's crypto capabilities

Martin Fernandez
2021-12-16T19:23:51Z

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..93581b31225e
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices-node
@@ -0,0 +1,10 @@
+What: /sys/devices/system/node/nodeX/crypto_capable
+Date: December 2021
+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
+ 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 b5a4ba18f9f9..67b0e2fa93b1 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