[PATCH v4 10/14] gunyah: sysfs: Add node to describe supported features

Elliot Berman
2022-09-28T19:58:31Z

Add a sysfs node to list the features that the Gunyah hypervisor and
Linux supports. For now, Linux support cspace (capability IDs) and
message queues, so only report those..

Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
Documentation/ABI/testing/sysfs-hypervisor-gunyah | 15 +++++++++++++++
drivers/virt/gunyah/sysfs.c | 15 +++++++++++++++
2 files changed, 30 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-hypervisor-gunyah b/Documentation/ABI/testing/sysfs-hypervisor-gunyah
index 7d74e74e9edd..6d0cde30355a 100644
--- a/Documentation/ABI/testing/sysfs-hypervisor-gunyah
+++ b/Documentation/ABI/testing/sysfs-hypervisor-gunyah
@@ -1,3 +1,18 @@
+What: /sys/hypervisor/gunyah/features
+Date: October 2022
+KernelVersion: 6.1
+Contact: linux-arm-msm@vger.kernel.org
+Description: If running under Gunyah:
+ Space separated list of features supported by Linux and Gunyah:
+ "cspace": Gunyah devices
+ "doorbell": Sending/receiving virtual interrupts via Gunyah doorbells
+ "message-queue": Sending/receiving messages via Gunyah message queues
+ "vic": Interrupt lending
+ "vpm": Virtual platform management
+ "vcpu": Virtual CPU management
+ "memextent": Memory lending/management
+ "trace": Gunyah hypervisor tracing
+
What: /sys/hypervisor/gunyah/api
Date: October 2022
KernelVersion: 6.1
diff --git a/drivers/virt/gunyah/sysfs.c b/drivers/virt/gunyah/sysfs.c
index ec11510cbece..f8ec0553c197 100644
--- a/drivers/virt/gunyah/sysfs.c
+++ b/drivers/virt/gunyah/sysfs.c
@@ -25,9 +25,24 @@ static ssize_t variant_show(struct kobject *kobj, struct kobj_attribute *attr, c
}
static struct kobj_attribute variant_attr = __ATTR_RO(variant);

+static ssize_t features_show(struct kobject *kobj, struct kobj_attribute *attr, char *buffer)
+{
+ int len = 0;
+
+ if (GH_IDENTIFY_PARTITION_CSPACE(gunyah_api.flags))
+ len += sysfs_emit_at(buffer, len, "cspace ");
+ if (GH_IDENTIFY_MSGQUEUE(gunyah_api.flags))
+ len += sysfs_emit_at(buffer, len, "message-queue ");
+
+ len += sysfs_emit_at(buffer, len, "\n");
+ return len;
+}
+static struct kobj_attribute features_attr = __ATTR_RO(features);
+
static struct attribute *gunyah_attrs[] = {
&api_attr.attr,
&variant_attr.attr,
+ &features_attr.attr,
NULL
};

--
2.25.1