diff --git a/target-i386/helper.c b/target-i386/helper.c
index 9a50da6..a706cae 100644
--- a/target-i386/helper.c
+++ b/target-i386/helper.c
@@ -44,7 +44,7 @@ static const char *feature_name[] = {
 static const char *ext_feature_name[] = {
     "pni" /* Intel,AMD sse3 */, NULL, NULL, "monitor", "ds_cpl", "vmx", NULL /* Linux smx */, "est",
     "tm2", "ssse3", "cid", NULL, NULL, "cx16", "xtpr", NULL,
-    NULL, NULL, "dca", NULL, NULL, "x2apic", NULL, "popcnt",
+    NULL, NULL, "dca", "sse4.1", "sse4.2", "x2apic", NULL, "popcnt",
     NULL, NULL, NULL, NULL, NULL, NULL, NULL, "hypervisor",
 };
 static const char *ext2_feature_name[] = {
@@ -60,6 +60,18 @@ static const char *ext3_feature_name[] = {
     NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
 };
 
+/* collects per-function cpuid data
+ */
+typedef struct model_features_t {
+    uint32_t *guest_feat;
+    uint32_t *host_feat;
+    uint32_t check_feat;
+    const char **flag_names;
+    uint32_t cpuid;
+    } model_features_t;
+
+int check_cpuid = 0;
+
 static void add_flagname_to_bitmaps(const char *flagname, uint32_t *features,
                                     uint32_t *ext_features,
                                     uint32_t *ext2_features,
@@ -171,6 +183,139 @@ static x86_def_t x86_defs[] = {
         .model_id = "AMD Phenom(tm) 9550 Quad-Core Processor"
     },
     {
+        .name = "Merom",
+        .level = 2,
+        .vendor1 = CPUID_VENDOR_INTEL_1,
+        .vendor2 = CPUID_VENDOR_INTEL_2,
+        .vendor3 = CPUID_VENDOR_INTEL_3,
+        .family = 6,	/* P6 */
+        .model = 2,
+        .stepping = 3,
+        .features = PPRO_FEATURES | 
+        /* these features are needed for Win64 and aren't fully implemented */
+            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
+        /* this feature is needed for Solaris and isn't fully implemented */
+            CPUID_PSE36,
+        .ext_features = CPUID_EXT_SSE3,		/* from qemu64 */
+        .ext2_features = (PPRO_FEATURES & 0x0183F3FF) | 
+            CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
+        .ext3_features = CPUID_EXT3_SVM,	/* from qemu64 */
+        .xlevel = 0x8000000A,
+        .model_id = "Intel Merom Core 2",
+    },
+    {
+        .name = "Penryn",
+        .level = 2,
+        .vendor1 = CPUID_VENDOR_INTEL_1,
+        .vendor2 = CPUID_VENDOR_INTEL_2,
+        .vendor3 = CPUID_VENDOR_INTEL_3,
+        .family = 6,	/* P6 */
+        .model = 2,
+        .stepping = 3,
+        .features = PPRO_FEATURES | 
+        /* these features are needed for Win64 and aren't fully implemented */
+            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
+        /* this feature is needed for Solaris and isn't fully implemented */
+            CPUID_PSE36,
+        .ext_features = CPUID_EXT_SSE3 |
+            CPUID_EXT_CX16 | CPUID_EXT_SSSE3 | CPUID_EXT_SSE41,
+        .ext2_features = (PPRO_FEATURES & 0x0183F3FF) | 
+            CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
+        .ext3_features = CPUID_EXT3_SVM,
+        .xlevel = 0x8000000A,
+        .model_id = "Intel Penryn Core 2",
+    },
+    {
+        .name = "Nehalem",
+        .level = 2,
+        .vendor1 = CPUID_VENDOR_INTEL_1,
+        .vendor2 = CPUID_VENDOR_INTEL_2,
+        .vendor3 = CPUID_VENDOR_INTEL_3,
+        .family = 6,	/* P6 */
+        .model = 2,
+        .stepping = 3,
+        .features = PPRO_FEATURES | 
+        /* these features are needed for Win64 and aren't fully implemented */
+            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
+        /* this feature is needed for Solaris and isn't fully implemented */
+            CPUID_PSE36,
+        .ext_features = CPUID_EXT_SSE3 |
+            CPUID_EXT_CX16 | CPUID_EXT_SSSE3 | CPUID_EXT_SSE41 |
+            CPUID_EXT_SSE42 | CPUID_EXT_POPCNT,
+        .ext2_features = (PPRO_FEATURES & 0x0183F3FF) | 
+            CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
+        .ext3_features = CPUID_EXT3_SVM,
+        .xlevel = 0x8000000A,
+        .model_id = "Intel Nehalem Core i7",
+    },
+    {
+        .name = "Opteron_G1",
+        .level = 5,
+        .vendor1 = CPUID_VENDOR_INTEL_1,
+        .vendor2 = CPUID_VENDOR_INTEL_2,
+        .vendor3 = CPUID_VENDOR_INTEL_3,
+        .family = 15,
+        .model = 6,
+        .stepping = 1,
+        .features = PPRO_FEATURES | 
+        /* these features are needed for Win64 and aren't fully implemented */
+            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
+        /* this feature is needed for Solaris and isn't fully implemented */
+            CPUID_PSE36,
+        .ext_features = CPUID_EXT_SSE3 | CPUID_EXT_MONITOR,
+        .ext2_features = (PPRO_FEATURES & 0x0183F3FF) | 
+            CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
+        .ext3_features = CPUID_EXT3_SVM,
+        .xlevel = 0x80000008,
+        .model_id = "AMD Opteron G1",
+    },
+    {
+        .name = "Opteron_G2",
+        .level = 5,
+        .vendor1 = CPUID_VENDOR_INTEL_1,
+        .vendor2 = CPUID_VENDOR_INTEL_2,
+        .vendor3 = CPUID_VENDOR_INTEL_3,
+        .family = 15,
+        .model = 6,
+        .stepping = 1,
+        .features = PPRO_FEATURES | 
+        /* these features are needed for Win64 and aren't fully implemented */
+            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
+        /* this feature is needed for Solaris and isn't fully implemented */
+            CPUID_PSE36 | CPUID_EXT_CX16,
+        .ext_features = CPUID_EXT_SSE3 | CPUID_EXT_MONITOR,
+        .ext2_features = (PPRO_FEATURES & 0x0183F3FF) | 
+            CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX |
+            CPUID_EXT2_RDTSCP,
+        .ext3_features = CPUID_EXT3_SVM,
+        .xlevel = 0x80000008,
+        .model_id = "AMD Opteron G2",
+    },
+    {
+        .name = "Opteron_G3",
+        .level = 5,
+        .vendor1 = CPUID_VENDOR_INTEL_1,
+        .vendor2 = CPUID_VENDOR_INTEL_2,
+        .vendor3 = CPUID_VENDOR_INTEL_3,
+        .family = 15,
+        .model = 6,
+        .stepping = 1,
+        .features = PPRO_FEATURES | 
+        /* these features are needed for Win64 and aren't fully implemented */
+            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
+        /* this feature is needed for Solaris and isn't fully implemented */
+            CPUID_PSE36 | CPUID_EXT_CX16,
+        .ext_features = CPUID_EXT_SSE3 | CPUID_EXT_MONITOR | CPUID_EXT_POPCNT,
+        .ext2_features = (PPRO_FEATURES & 0x0183F3FF) | 
+            CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX |
+            CPUID_EXT2_RDTSCP,
+        .ext3_features = CPUID_EXT3_SVM | CPUID_EXT3_SSE4A | CPUID_EXT3_ABM |
+            CPUID_EXT3_MISALIGNSSE,
+        .xlevel = 0x80000008,
+        .model_id = "AMD Opteron G3",
+    },
+        /* this feature is needed for Solaris and isn't fully implemented */
+    {
         .name = "core2duo",
         .level = 10,
         .family = 6,
@@ -319,7 +464,7 @@ static x86_def_t x86_defs[] = {
         /* Missing: .ext3_features = CPUID_EXT3_LAHF_LM */
         .xlevel = 0x8000000A,
         .model_id = "Intel(R) Atom(TM) CPU N270   @ 1.60GHz",
-    },
+    }
 };
 
 static void host_cpuid(uint32_t function, uint32_t count, uint32_t *eax,
@@ -370,6 +515,51 @@ static int cpu_x86_fill_host(x86_def_t *x86_cpu_def)
     return 0;
 }
 
+static int unavailable_host_feature(struct model_features_t *f, uint32_t mask)
+{
+    int i;
+
+    for (i = 0; i < 32; ++i)
+        if (1 << i & mask) {
+            fprintf(stderr, "warning: host cpuid %04x_%04x lacks requested"
+                " flag '%s' [0x%08x]\n",
+                f->cpuid >> 16, f->cpuid & 0xffff,
+                f->flag_names[i] ? f->flag_names[i] : "[reserved]", mask);
+            break;
+        }
+    return 0;
+}
+
+/* best effort attempt to inform user requested cpu flags aren't making
+ * their way to the guest.  Note: ft[].check_feat ideally should be
+ * specified via a guest_def field to suppress report of extraneous flags.
+ */
+static int check_features_against_host(x86_def_t *guest_def)
+{
+    x86_def_t host_def;
+    uint32_t mask;
+    int rv, i;
+    struct model_features_t ft[] = {
+        {&guest_def->features, &host_def.features,
+            ~0, feature_name, 0x00000000},
+        {&guest_def->ext_features, &host_def.ext_features,
+            ~CPUID_EXT_HYPERVISOR, ext_feature_name, 0x00000001},
+        {&guest_def->ext2_features, &host_def.ext2_features,
+            ~PPRO_FEATURES, ext2_feature_name, 0x80000000},
+        {&guest_def->ext3_features, &host_def.ext3_features,
+            ~CPUID_EXT3_SVM, ext3_feature_name, 0x80000001}};
+
+    cpu_x86_fill_host(&host_def);
+    for (rv = 0, i = 0; i < sizeof (ft) / sizeof (ft[0]); ++i)
+        for (mask = 1; mask; mask <<= 1)
+            if (ft[i].check_feat & mask && *ft[i].guest_feat & mask &&
+                !(*ft[i].host_feat & mask)) {
+                    unavailable_host_feature(&ft[i], mask);
+                    rv = 1;
+                }
+    return (rv);
+}
+
 static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *cpu_model)
 {
     unsigned int i;
@@ -473,6 +663,8 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *cpu_model)
                 fprintf(stderr, "unrecognized feature %s\n", featurestr);
                 goto error;
             }
+        } else if (!strcmp(featurestr, "check")) {
+            check_cpuid = 1;
         } else {
             fprintf(stderr, "feature string `%s' not in format (+feature|-feature|feature=xyz)\n", featurestr);
             goto error;
@@ -487,6 +679,9 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *cpu_model)
     x86_cpu_def->ext_features &= ~minus_ext_features;
     x86_cpu_def->ext2_features &= ~minus_ext2_features;
     x86_cpu_def->ext3_features &= ~minus_ext3_features;
+    if (check_cpuid)
+        check_features_against_host(x86_cpu_def);
+
     free(s);
     return 0;
 
