xen/hvm: If we fail to fetch an HVM parameter print out which flag it is.

Makes it easier to troubleshoot in the field.

Acked-by: Ian Campbell <ian.campbell@citrix.com>
[v1: Use macro per Ian's suggestion]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 32 insertions, 2 deletions

diff --git a/include/xen/hvm.h b/include/xen/hvm.h
index b193fa2f9fdd..13e43e41637d 100644
--- a/include/xen/hvm.h
+++ b/include/xen/hvm.h
@@ -5,6 +5,36 @@
 #include <xen/interface/hvm/params.h>
 #include <asm/xen/hypercall.h>
 
+static const char *param_name(int op)
+{
+#define PARAM(x) [HVM_PARAM_##x] = #x
+        static const char *const names[] = {
+                PARAM(CALLBACK_IRQ),
+                PARAM(STORE_PFN),
+                PARAM(STORE_EVTCHN),
+                PARAM(PAE_ENABLED),
+                PARAM(IOREQ_PFN),
+                PARAM(BUFIOREQ_PFN),
+                PARAM(TIMER_MODE),
+                PARAM(HPET_ENABLED),
+                PARAM(IDENT_PT),
+                PARAM(DM_DOMAIN),
+                PARAM(ACPI_S_STATE),
+                PARAM(VM86_TSS),
+                PARAM(VPT_ALIGN),
+                PARAM(CONSOLE_PFN),
+                PARAM(CONSOLE_EVTCHN),
+        };
+#undef PARAM
+
+        if (op >= ARRAY_SIZE(names))
+                return "unknown";
+
+        if (!names[op])
+                return "reserved";
+
+        return names[op];
+}
 static inline int hvm_get_parameter(int idx, uint64_t *value)
 {
         struct xen_hvm_param xhv;
@@ -14,8 +44,8 @@ static inline int hvm_get_parameter(int idx, uint64_t *value)
         xhv.index = idx;
         r = HYPERVISOR_hvm_op(HVMOP_get_param, &xhv);
         if (r < 0) {
-                printk(KERN_ERR "Cannot get hvm parameter %d: %d!\n",
-                        idx, r);
+                printk(KERN_ERR "Cannot get hvm parameter %s (%d): %d!\n",
+                        param_name(idx), idx, r);
                 return r;
         }
         *value = xhv.value;