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Commit 84b76257 authored by Juergen Gross's avatar Juergen Gross
Browse files

xen: add sysfs node for hypervisor build id 



For support of Xen hypervisor live patching the hypervisor build id is
needed. Add a node /sys/hypervisor/properties/buildid containing the
information.

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent a714c286

Documentation/ABI/testing/sysfs-hypervisor-xen

+10 −1
Original line number Diff line number Diff line 
What:		/sys/hypervisor/guest_type

Date:		May 2017

Date:		June 2017

KernelVersion:	4.13

Contact:	xen-devel@lists.xenproject.org

Description:	If running under Xen:
@@ -32,3 +32,12 @@ Description: If running under Xen: 
		Describes Xen PMU features (as an integer). A set bit indicates

		that the corresponding feature is enabled. See

		include/xen/interface/xenpmu.h for available features



What:		/sys/hypervisor/properties/buildid

Date:		June 2017

KernelVersion:	4.13

Contact:	xen-devel@lists.xenproject.org

Description:	If running under Xen:

		Build id of the hypervisor, needed for hypervisor live patching.

		Might return "<denied>" in case of special security settings

		in the hypervisor.

drivers/xen/sys-hypervisor.c

+28 −0
Original line number Diff line number Diff line
@@ -356,12 +356,40 @@ static ssize_t features_show(struct hyp_sysfs_attr *attr, char *buffer) 


HYPERVISOR_ATTR_RO(features);



static ssize_t buildid_show(struct hyp_sysfs_attr *attr, char *buffer)

{

	ssize_t ret;

	struct xen_build_id *buildid;



	ret = HYPERVISOR_xen_version(XENVER_build_id, NULL);

	if (ret < 0) {

		if (ret == -EPERM)

			ret = sprintf(buffer, "<denied>");

		return ret;

	}



	buildid = kmalloc(sizeof(*buildid) + ret, GFP_KERNEL);

	if (!buildid)

		return -ENOMEM;



	buildid->len = ret;

	ret = HYPERVISOR_xen_version(XENVER_build_id, buildid);

	if (ret > 0)

		ret = sprintf(buffer, "%s", buildid->buf);

	kfree(buildid);



	return ret;

}



HYPERVISOR_ATTR_RO(buildid);



static struct attribute *xen_properties_attrs[] = {

	&capabilities_attr.attr,

	&changeset_attr.attr,

	&virtual_start_attr.attr,

	&pagesize_attr.attr,

	&features_attr.attr,

	&buildid_attr.attr,

	NULL

};