From b8661036e7465eab99f988cec3fe37e35536eb40 Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Wed, 14 Jun 2017 17:12:45 +0200
Subject: [PATCH v5] xen: add sysfs node for guest type
Currently there is no reliable user interface inside a Xen guest to
determine its type (e.g. HVM, PV or PVH). Instead of letting user mode
try to determine this by various rather hacky mechanisms (parsing of
boot messages before they are gone, trying to make use of known subtle
differences in behavior of some instructions), add a sysfs node
/sys/hypervisor/guest_type to explicitly deliver this information as
it is known to the kernel.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V4:
- use xen_domain_type instead of introducing xen_guest_type
(Boris Ostrovsky)
V2:
- remove PVHVM guest type (Andrew Cooper)
- move description to Documentation/ABI/testing/sysfs-hypervisor-xen
(Boris Ostrovsky)
- make xen_guest_type const char * (Jan Beulich)
- modify standard ARM guest type to "Xen"
---
.../{sysfs-hypervisor-pmu => sysfs-hypervisor-xen} | 15 ++++++++--
MAINTAINERS | 2 +-
drivers/xen/sys-hypervisor.c | 34 ++++++++++++++++++++++
3 files changed, 48 insertions(+), 3 deletions(-)
rename Documentation/ABI/testing/{sysfs-hypervisor-pmu => sysfs-hypervisor-xen} (67%)
similarity index 67%
rename from Documentation/ABI/testing/sysfs-hypervisor-pmu
rename to Documentation/ABI/testing/sysfs-hypervisor-xen
@@ -1,8 +1,19 @@
+What: /sys/hypervisor/guest_type
+Date: May 2017
+KernelVersion: 4.13
+Contact: xen-devel@lists.xenproject.org
+Description: If running under Xen:
+ Type of guest:
+ "Xen": standard guest type on arm
+ "HVM": fully virtualized guest (x86)
+ "PV": paravirtualized guest (x86)
+ "PVH": fully virtualized guest without legacy emulation (x86)
+
What: /sys/hypervisor/pmu/pmu_mode
Date: August 2015
KernelVersion: 4.3
Contact: Boris Ostrovsky <boris.ostrovsky@oracle.com>
-Description:
+Description: If running under Xen:
Describes mode that Xen's performance-monitoring unit (PMU)
uses. Accepted values are
"off" -- PMU is disabled
@@ -17,7 +28,7 @@ What: /sys/hypervisor/pmu/pmu_features
Date: August 2015
KernelVersion: 4.3
Contact: Boris Ostrovsky <boris.ostrovsky@oracle.com>
-Description:
+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
@@ -13983,7 +13983,7 @@ F: arch/x86/include/asm/xen/
F: include/xen/
F: include/uapi/xen/
F: Documentation/ABI/stable/sysfs-hypervisor-xen
-F: Documentation/ABI/testing/sysfs-hypervisor-pmu
+F: Documentation/ABI/testing/sysfs-hypervisor-xen
XEN HYPERVISOR ARM
M: Stefano Stabellini <sstabellini@kernel.org>
@@ -50,6 +50,35 @@ static int __init xen_sysfs_type_init(void)
return sysfs_create_file(hypervisor_kobj, &type_attr.attr);
}
+static ssize_t guest_type_show(struct hyp_sysfs_attr *attr, char *buffer)
+{
+ const char *type;
+
+ switch (xen_domain_type) {
+ case XEN_NATIVE:
+ /* ARM only. */
+ type = "Xen";
+ break;
+ case XEN_PV_DOMAIN:
+ type = "PV";
+ break;
+ case XEN_HVM_DOMAIN:
+ type = xen_pvh_domain() ? "PVH" : "HVM";
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return sprintf(buffer, "%s\n", type);
+}
+
+HYPERVISOR_ATTR_RO(guest_type);
+
+static int __init xen_sysfs_guest_type_init(void)
+{
+ return sysfs_create_file(hypervisor_kobj, &guest_type_attr.attr);
+}
+
/* xen version attributes */
static ssize_t major_show(struct hyp_sysfs_attr *attr, char *buffer)
{
@@ -471,6 +500,9 @@ static int __init hyper_sysfs_init(void)
ret = xen_sysfs_type_init();
if (ret)
goto out;
+ ret = xen_sysfs_guest_type_init();
+ if (ret)
+ goto guest_type_out;
ret = xen_sysfs_version_init();
if (ret)
goto version_out;
@@ -502,6 +534,8 @@ static int __init hyper_sysfs_init(void)
comp_out:
sysfs_remove_group(hypervisor_kobj, &version_group);
version_out:
+ sysfs_remove_file(hypervisor_kobj, &guest_type_attr.attr);
+guest_type_out:
sysfs_remove_file(hypervisor_kobj, &type_attr.attr);
out:
return ret;
--
2.12.3