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-rw-r--r--Documentation/ABI/stable/sysfs-hypervisor-xen13
-rw-r--r--drivers/xen/sys-hypervisor.c69
2 files changed, 78 insertions, 4 deletions
diff --git a/Documentation/ABI/stable/sysfs-hypervisor-xen b/Documentation/ABI/stable/sysfs-hypervisor-xen
index 748593c64568..be9ca9981bb1 100644
--- a/Documentation/ABI/stable/sysfs-hypervisor-xen
+++ b/Documentation/ABI/stable/sysfs-hypervisor-xen
@@ -120,3 +120,16 @@ Contact: xen-devel@lists.xenproject.org
Description: If running under Xen:
The Xen version is in the format <major>.<minor><extra>
This is the <minor> part of it.
+
+What: /sys/hypervisor/start_flags/*
+Date: March 2023
+KernelVersion: 6.3.0
+Contact: xen-devel@lists.xenproject.org
+Description: If running under Xen:
+ All bits in Xen's start-flags are represented as
+ boolean files, returning '1' if set, '0' otherwise.
+ This takes the place of the defunct /proc/xen/capabilities,
+ which would contain "control_d" on dom0, and be empty
+ otherwise. This flag is now exposed as "initdomain" in
+ addition to the "privileged" flag; all other possible flags
+ are accessible as "unknownXX".
diff --git a/drivers/xen/sys-hypervisor.c b/drivers/xen/sys-hypervisor.c
index fcb0792f090e..ca092db8f498 100644
--- a/drivers/xen/sys-hypervisor.c
+++ b/drivers/xen/sys-hypervisor.c
@@ -31,7 +31,10 @@ struct hyp_sysfs_attr {
struct attribute attr;
ssize_t (*show)(struct hyp_sysfs_attr *, char *);
ssize_t (*store)(struct hyp_sysfs_attr *, const char *, size_t);
- void *hyp_attr_data;
+ union {
+ void *hyp_attr_data;
+ unsigned long hyp_attr_value;
+ };
};
static ssize_t type_show(struct hyp_sysfs_attr *attr, char *buffer)
@@ -399,6 +402,60 @@ static int __init xen_sysfs_properties_init(void)
return sysfs_create_group(hypervisor_kobj, &xen_properties_group);
}
+#define FLAG_UNAME "unknown"
+#define FLAG_UNAME_FMT FLAG_UNAME "%02u"
+#define FLAG_UNAME_MAX sizeof(FLAG_UNAME "XX")
+#define FLAG_COUNT (sizeof(xen_start_flags) * BITS_PER_BYTE)
+static_assert(sizeof(xen_start_flags) <=
+ sizeof_field(struct hyp_sysfs_attr, hyp_attr_value));
+
+static ssize_t flag_show(struct hyp_sysfs_attr *attr, char *buffer)
+{
+ char *p = buffer;
+
+ *p++ = '0' + ((xen_start_flags & attr->hyp_attr_value) != 0);
+ *p++ = '\n';
+ return p - buffer;
+}
+
+#define FLAG_NODE(flag, node) \
+ [ilog2(flag)] = { \
+ .attr = { .name = #node, .mode = 0444 },\
+ .show = flag_show, \
+ .hyp_attr_value = flag \
+ }
+
+/*
+ * Add new, known flags here. No other changes are required, but
+ * note that each known flag wastes one entry in flag_unames[].
+ * The code/complexity machinations to avoid this isn't worth it
+ * for a few entries, but keep it in mind.
+ */
+static struct hyp_sysfs_attr flag_attrs[FLAG_COUNT] = {
+ FLAG_NODE(SIF_PRIVILEGED, privileged),
+ FLAG_NODE(SIF_INITDOMAIN, initdomain)
+};
+static struct attribute_group xen_flags_group = {
+ .name = "start_flags",
+ .attrs = (struct attribute *[FLAG_COUNT + 1]){}
+};
+static char flag_unames[FLAG_COUNT][FLAG_UNAME_MAX];
+
+static int __init xen_sysfs_flags_init(void)
+{
+ for (unsigned fnum = 0; fnum != FLAG_COUNT; fnum++) {
+ if (likely(flag_attrs[fnum].attr.name == NULL)) {
+ sprintf(flag_unames[fnum], FLAG_UNAME_FMT, fnum);
+ flag_attrs[fnum].attr.name = flag_unames[fnum];
+ flag_attrs[fnum].attr.mode = 0444;
+ flag_attrs[fnum].show = flag_show;
+ flag_attrs[fnum].hyp_attr_value = 1 << fnum;
+ }
+ xen_flags_group.attrs[fnum] = &flag_attrs[fnum].attr;
+ }
+ return sysfs_create_group(hypervisor_kobj, &xen_flags_group);
+}
+
#ifdef CONFIG_XEN_HAVE_VPMU
struct pmu_mode {
const char *name;
@@ -539,18 +596,22 @@ static int __init hyper_sysfs_init(void)
ret = xen_sysfs_properties_init();
if (ret)
goto prop_out;
+ ret = xen_sysfs_flags_init();
+ if (ret)
+ goto flags_out;
#ifdef CONFIG_XEN_HAVE_VPMU
if (xen_initial_domain()) {
ret = xen_sysfs_pmu_init();
if (ret) {
- sysfs_remove_group(hypervisor_kobj,
- &xen_properties_group);
- goto prop_out;
+ sysfs_remove_group(hypervisor_kobj, &xen_flags_group);
+ goto flags_out;
}
}
#endif
goto out;
+flags_out:
+ sysfs_remove_group(hypervisor_kobj, &xen_properties_group);
prop_out:
sysfs_remove_file(hypervisor_kobj, &uuid_attr.attr);
uuid_out: