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-rw-r--r--drivers/xen/features.c20
1 files changed, 19 insertions, 1 deletions
diff --git a/drivers/xen/features.c b/drivers/xen/features.c
index 25c053b09605..87f1828d40d5 100644
--- a/drivers/xen/features.c
+++ b/drivers/xen/features.c
@@ -9,13 +9,26 @@
#include <linux/types.h>
#include <linux/cache.h>
#include <linux/export.h>
+#include <linux/printk.h>
#include <asm/xen/hypercall.h>
+#include <xen/xen.h>
#include <xen/interface/xen.h>
#include <xen/interface/version.h>
#include <xen/features.h>
+/*
+ * Linux kernel expects at least Xen 4.0.
+ *
+ * Assume some features to be available for that reason (depending on guest
+ * mode, of course).
+ */
+#define chk_required_feature(f) { \
+ if (!xen_feature(f)) \
+ panic("Xen: feature %s not available!\n", #f); \
+ }
+
u8 xen_features[XENFEAT_NR_SUBMAPS * 32] __read_mostly;
EXPORT_SYMBOL_GPL(xen_features);
@@ -29,6 +42,11 @@ void xen_setup_features(void)
if (HYPERVISOR_xen_version(XENVER_get_features, &fi) < 0)
break;
for (j = 0; j < 32; j++)
- xen_features[i * 32 + j] = !!(fi.submap & 1<<j);
+ xen_features[i * 32 + j] = !!(fi.submap & 1U << j);
+ }
+
+ if (xen_pv_domain()) {
+ chk_required_feature(XENFEAT_mmu_pt_update_preserve_ad);
+ chk_required_feature(XENFEAT_gnttab_map_avail_bits);
}
}