diff -r b5fc70fadacc -r a5209d79d241 xen/include/public/arch-x86/xen.h
--- a/xen/include/public/arch-x86/xen.h	Fri Aug 17 09:06:44 2007 +0200
+++ b/xen/include/public/arch-x86/xen.h	Fri Aug 17 13:21:40 2007 +0200
@@ -81,6 +81,104 @@ DEFINE_XEN_GUEST_HANDLE(xen_pfn_t);
 #define MAX_VIRT_CPUS 32
 
 #ifndef __ASSEMBLY__
+
+/*
+ * Machine Check Architecure:
+ * structs are read-only and used to report all kinds of
+ * correctable and uncorrectable errors detected by the HW.
+ * Dom0 and DomU: register a handler to get notified.
+ * Dom0 only: Correctable errors are reported via VIRQ_MCA
+ * Dom0 and DomU: Uncorrectable errors are reported via nmi handlers
+ */
+#define MC_TYPE_GLOBAL 0
+#define MC_TYPE_BANK   1
+
+struct mcinfo_common {
+    uint16_t type;     /* structure type */
+    uint16_t size;     /* size of this struct in bytes */
+} __attribute__((packed));
+
+
+#define MC_FLAG_CORRECTABLE    (1 << 0)
+#define MC_FLAG_UNCORRECTABLE  (1 << 1)
+/* contains global x86 mc information */
+struct mcinfo_global {
+    struct mcinfo_common common;
+
+    uint16_t mc_domid; 
+    uint16_t mc_socketid;
+    uint16_t mc_coreid;
+    uint16_t mc_vcpu_id;
+    uint64_t mc_gstatus; /* global status */
+    uint32_t mc_flags;
+} __attribute__((packed));
+
+/* contains bank local x86 mc information */
+struct mcinfo_bank {
+    struct mcinfo_common common;
+
+    uint16_t mc_bank; /* bank nr */
+    uint64_t mc_status; /* bank status */
+    uint64_t mc_addr;
+    uint64_t mc_misc;
+} __attribute__((packed));
+
+
+/* sizeof(struct mcinfo_global) + 6 * sizeof(struct mcinfo_bank) == 200.
+ * This is enough space to store mc information of up to six banks.
+ */
+#define MCINFO_MAXSIZE (204 - sizeof(uint32_t))
+
+struct arch_mc_info {
+    /* Number of mcainfo_* entries in mi_data */
+    uint32_t mi_nentries;
+
+    uint8_t mi_data[MCINFO_MAXSIZE];
+};
+typedef struct arch_mc_info arch_mc_info_t;
+
+
+
+/* 
+ * OS's should use these instead of writing their own helper functions
+ * each with its own bugs and drawbacks.
+ */
+/* Prototype:
+ *    uint32_t x86_mcinfo_nentries(struct shared_info *si);
+ */
+#define x86_mcinfo_nentries(_si)    \
+    (_si)->arch.mc_info.mi_nentries
+/* Prototype:
+ *    struct mcinfo_common *x86_mcinfo_first(struct shared_info *si);
+ */
+#define x86_mcinfo_first(_si)       \
+    (struct mcinfo_common *)((_si)->arch.mc_info.mi_data)
+/* Prototype:
+ *    struct mcinfo_common *x86_mcinfo_next(struct mcinfo_common *mic);
+ */
+#define x86_mcinfo_next(_mic)       \
+   (struct mcinfo_common *)((uint8_t *)(_mic) + (_mic)->size)
+
+/* Prototype:
+ *    void x86_mcinfo_lookup(void *ret, struct shared_info *si, uint16_t type);
+ */
+#define x86_mcinfo_lookup(_ret, _si, _type)    \
+    do {                                                        \
+        uint32_t found, i;                                      \
+        struct mcinfo_common *_mic;                             \
+                                                                \
+        _mic = x86_mcinfo_first(_si);                           \
+        found = 0;                                              \
+        for (i = 0; i < x86_mcinfo_nentries(_si); i++) {        \
+            if (_mic->type == (_type))                          \
+                found = 1;                                      \
+            else                                                \
+                _mic = x86_mcinfo_next(_mic);                   \
+        }                                                       \
+        (_ret) = found ? _mic : NULL;                           \
+    } while (0)
+
+
 
 typedef unsigned long xen_ulong_t;
 
@@ -173,6 +271,7 @@ struct arch_shared_info {
     /* Frame containing list of mfns containing list of mfns containing p2m. */
     xen_pfn_t     pfn_to_mfn_frame_list_list;
     unsigned long nmi_reason;
+    struct arch_mc_info mc_info; /* machine check information */
     uint64_t pad[32];
 };
 typedef struct arch_shared_info arch_shared_info_t;
diff -r b5fc70fadacc -r a5209d79d241 xen/include/public/foreign/reference.size
--- a/xen/include/public/foreign/reference.size	Fri Aug 17 09:06:44 2007 +0200
+++ b/xen/include/public/foreign/reference.size	Fri Aug 17 13:21:40 2007 +0200
@@ -13,6 +13,7 @@ arch_vcpu_info            |      24     
 arch_vcpu_info            |      24      16       0
 vcpu_time_info            |      32      32      32
 vcpu_info                 |      64      64      48
-arch_shared_info          |     268     280     272
-shared_info               |    2584    3368    4384
+arch_mc_info              |     204     204       -
+arch_shared_info          |     472     488     272
+shared_info               |    2788    3576    4384
 
diff -r b5fc70fadacc -r a5209d79d241 xen/include/public/foreign/structs.py
--- a/xen/include/public/foreign/structs.py	Fri Aug 17 09:06:44 2007 +0200
+++ b/xen/include/public/foreign/structs.py	Fri Aug 17 13:21:40 2007 +0200
@@ -15,6 +15,7 @@ structs = [ "start_info",
             "arch_vcpu_info",
             "vcpu_time_info",
             "vcpu_info",
+            "arch_mc_info",
             "arch_shared_info",
             "shared_info" ];