Add cpu model configuration support..

This is a reimplementation of prior versions which adds
the ability to define cpu models for contemporary processors.
The added models are likewise selected via -cpu <name>,
and are intended to displace the existing convention
of "-cpu qemu64" augmented with a series of feature flags.

A primary motivation was determination of a least common
denominator within a given processor class to simplify guest
migration.  It is still possible to modify an arbitrary model
via additional feature flags however the goal here was to
make doing so unnecessary in typical usage.  The other
consideration was providing models names reflective of
current processors.  Both AMD and Intel have reviewed the
models in terms of balancing generality of migration vs.
excessive feature downgrade relative to released silicon.

This version of the patch replaces the prior hard wired
definitions with a configuration file approach for new
models.  Existing models are thus far left as-is but may
easily be transitioned to (or may be overridden by) the
configuration file representation.

Proposed new model definitions are provided here for current
AMD and Intel processors.  Each model consists of a name
used to select it on the command line (-cpu <name>), and a
model_id which corresponds to a least common denominator
commercial instance of the processor class.

A table of names/model_ids may be queried via "-cpu ?model":

        :
    x86       Opteron_G3  AMD Opteron 23xx (Gen 3 Class Opteron)
    x86       Opteron_G2  AMD Opteron 22xx (Gen 2 Class Opteron)
    x86       Opteron_G1  AMD Opteron 240 (Gen 1 Class Opteron)
    x86          Nehalem  Intel Core i7 9xx (Nehalem Class Core i7)
    x86           Penryn  Intel Core 2 Duo P9xxx (Penryn Class Core 2)
    x86           Conroe  Intel Celeron_4x0 (Conroe/Merom Class Core 2)
        :

Also added is "-cpu ?dump" which exhaustively outputs all config
data for all defined models, and "-cpu ?cpuid" which enumerates
all qemu recognized CPUID feature flags.

The pseudo cpuid flag 'check' when added to the feature flag list
will warn when feature flags (either implicit in a cpu model or
explicit on the command line) would have otherwise been quietly
unavailable to a guest:

    # qemu-system-x86_64 ... -cpu Nehalem,check
    warning: host cpuid 0000_0001 lacks requested flag 'sse4.2|sse4_2' [0x00100000]
    warning: host cpuid 0000_0001 lacks requested flag 'popcnt' [0x00800000]

A similar 'enforce' pseudo flag exists which in addition
to the above causes qemu to error exit if requested flags are
unavailable.

Configuration data for a cpu model resides in the target config
file which by default will be installed as:

    /usr/local/etc/qemu/target-<arch>.conf

The format of this file should be self explanatory given the
definitions for the above six models and essentially mimics
the structure of the static x86_def_t x86_defs.

Encoding of cpuid flags names now allows aliases for both the
configuration file and the command line which reconciles some
Intel/AMD/Linux/Qemu naming differences.

This patch was tested relative to qemu.git.

Signed-off-by: john cooper <john.cooper@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

8 files changed, 556 insertions, 72 deletions

diff --git a/Makefile b/Makefile
index c72a05940f..c6629d6643 100644
--- a/Makefile
+++ b/Makefile
@@ -191,7 +191,11 @@ ifdef CONFIG_POSIX
 	$(INSTALL_DATA) qemu-nbd.8 "$(DESTDIR)$(mandir)/man8"
 endif
 
-install: all $(if $(BUILD_DOCS),install-doc)
+install-sysconfig:
+	$(INSTALL_DIR) "$(sysconfdir)/qemu"
+	$(INSTALL_DATA) sysconfigs/target/target-x86_64.conf "$(sysconfdir)/qemu"
+
+install: all $(if $(BUILD_DOCS),install-doc) install-sysconfig
 	$(INSTALL_DIR) "$(DESTDIR)$(bindir)"
 ifneq ($(TOOLS),)
 	$(INSTALL_PROG) $(STRIP_OPT) $(TOOLS) "$(DESTDIR)$(bindir)"
diff --git a/linux-user/main.c b/linux-user/main.c
index a0d8ce734b..1189dda603 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -2553,6 +2553,10 @@ int main(int argc, char **argv, char **envp)
     }
 
     cpu_model = NULL;
+#if defined(cpudef_setup)
+    cpudef_setup(); /* parse cpu definitions in target config file (TBD) */
+#endif
+
     optind = 1;
     for(;;) {
         if (optind >= argc)
@@ -2624,8 +2628,8 @@ int main(int argc, char **argv, char **envp)
             cpu_model = argv[optind++];
             if (cpu_model == NULL || strcmp(cpu_model, "?") == 0) {
 /* XXX: implement xxx_cpu_list for targets that still miss it */
-#if defined(cpu_list)
-                    cpu_list(stdout, &fprintf);
+#if defined(cpu_list_id)
+                cpu_list_id(stdout, &fprintf, "");
 #endif
                 exit(1);
             }
diff --git a/qemu-config.c b/qemu-config.c
index c3203c87f9..246fae6f99 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -242,6 +242,54 @@ QemuOptsList qemu_mon_opts = {
     },
 };
 
+QemuOptsList qemu_cpudef_opts = {
+    .name = "cpudef",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_cpudef_opts.head),
+    .desc = {
+        {
+            .name = "name",
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "level",
+            .type = QEMU_OPT_NUMBER,
+        },{
+            .name = "vendor",
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "family",
+            .type = QEMU_OPT_NUMBER,
+        },{
+            .name = "model",
+            .type = QEMU_OPT_NUMBER,
+        },{
+            .name = "stepping",
+            .type = QEMU_OPT_NUMBER,
+        },{
+            .name = "feature_edx",      /* cpuid 0000_0001.edx */
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "feature_ecx",      /* cpuid 0000_0001.ecx */
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "extfeature_edx",   /* cpuid 8000_0001.edx */
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "extfeature_ecx",   /* cpuid 8000_0001.ecx */
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "xlevel",
+            .type = QEMU_OPT_NUMBER,
+        },{
+            .name = "model_id",
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "vendor_override",
+            .type = QEMU_OPT_NUMBER,
+        },
+        { /* end of list */ }
+    },
+};
+
 static QemuOptsList *lists[] = {
     &qemu_drive_opts,
     &qemu_chardev_opts,
@@ -251,6 +299,7 @@ static QemuOptsList *lists[] = {
     &qemu_rtc_opts,
     &qemu_global_opts,
     &qemu_mon_opts,
+    &qemu_cpudef_opts,
     NULL,
 };
 
diff --git a/qemu-config.h b/qemu-config.h
index dd89ae4683..b335c42926 100644
--- a/qemu-config.h
+++ b/qemu-config.h
@@ -9,6 +9,7 @@ extern QemuOptsList qemu_net_opts;
 extern QemuOptsList qemu_rtc_opts;
 extern QemuOptsList qemu_global_opts;
 extern QemuOptsList qemu_mon_opts;
+extern QemuOptsList qemu_cpudef_opts;
 
 int qemu_set_option(const char *str);
 int qemu_global_option(const char *str);
diff --git a/sysconfigs/target/target-x86_64.conf b/sysconfigs/target/target-x86_64.conf
new file mode 100644
index 0000000000..43ad282b5c
--- /dev/null
+++ b/sysconfigs/target/target-x86_64.conf
@@ -0,0 +1,86 @@
+# x86 CPU MODELS
+
+[cpudef]
+   name = "Conroe"
+   level = "2"
+   vendor = "GenuineIntel"
+   family = "6"
+   model = "2"
+   stepping = "3"
+   feature_edx = "sse2 sse fxsr mmx pat cmov pge sep apic cx8 mce pae msr tsc pse de fpu    mtrr clflush mca pse36"
+   feature_ecx = "sse3 ssse3"
+   extfeature_edx = "fxsr mmx pat cmov pge apic cx8 mce pae msr tsc pse de fpu    lm syscall nx"
+   extfeature_ecx = "lahf_lm"
+   xlevel = "0x8000000A"
+   model_id = "Intel Celeron_4x0 (Conroe/Merom Class Core 2)"
+
+[cpudef]
+   name = "Penryn"
+   level = "2"
+   vendor = "GenuineIntel"
+   family = "6"
+   model = "2"
+   stepping = "3"
+   feature_edx = "sse2 sse fxsr mmx pat cmov pge sep apic cx8 mce pae msr tsc pse de fpu    mtrr clflush mca pse36"
+   feature_ecx = "sse3 cx16 ssse3 sse4.1"
+   extfeature_edx = "fxsr mmx pat cmov pge apic cx8 mce pae msr tsc pse de fpu    lm syscall nx"
+   extfeature_ecx = "lahf_lm"
+   xlevel = "0x8000000A"
+   model_id = "Intel Core 2 Duo P9xxx (Penryn Class Core 2)"
+
+[cpudef]
+   name = "Nehalem"
+   level = "2"
+   vendor = "GenuineIntel"
+   family = "6"
+   model = "2"
+   stepping = "3"
+   feature_edx = "sse2 sse fxsr mmx pat cmov pge sep apic cx8 mce pae msr tsc pse de fpu    mtrr clflush mca pse36"
+   feature_ecx = "sse3 cx16 ssse3 sse4.1 sse4.2 popcnt"
+   extfeature_edx = "fxsr mmx pat cmov pge apic cx8 mce pae msr tsc pse de fpu    lm syscall nx"
+   extfeature_ecx = "lahf_lm"
+   xlevel = "0x8000000A"
+   model_id = "Intel Core i7 9xx (Nehalem Class Core i7)"
+
+[cpudef]
+   name = "Opteron_G1"
+   level = "5"
+   vendor = "AuthenticAMD"
+   family = "15"
+   model = "6"
+   stepping = "1"
+   feature_edx = "sse2 sse fxsr mmx pat cmov pge sep apic cx8 mce pae msr tsc pse de fpu    mtrr clflush mca pse36"
+   feature_ecx = "sse3"
+   extfeature_edx = "fxsr mmx pat cmov pge apic cx8 mce pae msr tsc pse de fpu    lm syscall nx"
+#   extfeature_ecx = ""
+   xlevel = "0x80000008"
+   model_id = "AMD Opteron 240 (Gen 1 Class Opteron)"
+
+[cpudef]
+   name = "Opteron_G2"
+   level = "5"
+   vendor = "AuthenticAMD"
+   family = "15"
+   model = "6"
+   stepping = "1"
+   feature_edx = "sse2 sse fxsr mmx pat cmov pge sep apic cx8 mce pae msr tsc pse de fpu    mtrr clflush mca pse36"
+   feature_ecx = "sse3 cx16"
+   extfeature_edx = "fxsr mmx pat cmov pge apic cx8 mce pae msr tsc pse de fpu    lm syscall nx rdtscp"
+   extfeature_ecx = "svm lahf_lm"
+   xlevel = "0x80000008"
+   model_id = "AMD Opteron 22xx (Gen 2 Class Opteron)"
+
+[cpudef]
+   name = "Opteron_G3"
+   level = "5"
+   vendor = "AuthenticAMD"
+   family = "15"
+   model = "6"
+   stepping = "1"
+   feature_edx = "sse2 sse fxsr mmx pat cmov pge sep apic cx8 mce pae msr tsc pse de fpu    mtrr clflush mca pse36"
+   feature_ecx = "sse3 cx16 monitor popcnt"
+   extfeature_edx = "fxsr mmx pat cmov pge apic cx8 mce pae msr tsc pse de fpu    lm syscall nx rdtscp"
+   extfeature_ecx = "svm sse4a  abm misalignsse lahf_lm"
+   xlevel = "0x80000008"
+   model_id = "AMD Opteron 23xx (Gen 3 Class Opteron)"
+
diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 216b00e503..ef7d951fcc 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -723,8 +723,10 @@ typedef struct CPUX86State {
 CPUX86State *cpu_x86_init(const char *cpu_model);
 int cpu_x86_exec(CPUX86State *s);
 void cpu_x86_close(CPUX86State *s);
-void x86_cpu_list (FILE *f, int (*cpu_fprintf)(FILE *f, const char *fmt,
-                                                 ...));
+void x86_cpu_list (FILE *f, int (*cpu_fprintf)(FILE *f, const char *fmt, ...),
+                   const char *optarg);
+void x86_cpudef_setup(void);
+
 int cpu_get_pic_interrupt(CPUX86State *s);
 /* MSDOS compatibility mode FPU exception support */
 void cpu_set_ferr(CPUX86State *s);
@@ -876,7 +878,8 @@ uint64_t cpu_get_tsc(CPUX86State *env);
 #define cpu_exec cpu_x86_exec
 #define cpu_gen_code cpu_x86_gen_code
 #define cpu_signal_handler cpu_x86_signal_handler
-#define cpu_list x86_cpu_list
+#define cpu_list_id x86_cpu_list
+#define cpudef_setup	x86_cpudef_setup
 
 #define CPU_SAVE_VERSION 11
 
diff --git a/target-i386/helper.c b/target-i386/helper.c
index 70762bb10a..7cda864b7b 100644
--- a/target-i386/helper.c
+++ b/target-i386/helper.c
@@ -29,33 +29,52 @@
 #include "kvm.h"
 
 //#define DEBUG_MMU
+#include "qemu-option.h"
+#include "qemu-config.h"
 
 /* feature flags taken from "Intel Processor Identification and the CPUID
- * Instruction" and AMD's "CPUID Specification". In cases of disagreement
- * about feature names, the Linux name is used. */
+ * Instruction" and AMD's "CPUID Specification".  In cases of disagreement
+ * between feature naming conventions, aliases may be added.
+ */
 static const char *feature_name[] = {
-    "fpu", "vme", "de", "pse", "tsc", "msr", "pae", "mce",
-    "cx8", "apic", NULL, "sep", "mtrr", "pge", "mca", "cmov",
-    "pat", "pse36", "pn" /* Intel psn */, "clflush" /* Intel clfsh */, NULL, "ds" /* Intel dts */, "acpi", "mmx",
-    "fxsr", "sse", "sse2", "ss", "ht" /* Intel htt */, "tm", "ia64", "pbe",
+    "fpu", "vme", "de", "pse",
+    "tsc", "msr", "pae", "mce",
+    "cx8", "apic", NULL, "sep",
+    "mtrr", "pge", "mca", "cmov",
+    "pat", "pse36", "pn" /* Intel psn */, "clflush" /* Intel clfsh */,
+    NULL, "ds" /* Intel dts */, "acpi", "mmx",
+    "fxsr", "sse", "sse2", "ss",
+    "ht" /* Intel htt */, "tm", "ia64", "pbe",
 };
 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, NULL, NULL, "popcnt",
-    NULL, NULL, NULL, NULL, NULL, NULL, NULL, "hypervisor",
+    "pni|sse3" /* Intel,AMD sse3 */, NULL, NULL, "monitor",
+    "ds_cpl", "vmx", NULL /* Linux smx */, "est",
+    "tm2", "ssse3", "cid", NULL,
+    NULL, "cx16", "xtpr", NULL,
+    NULL, NULL, "dca", "sse4.1|sse4_1",
+    "sse4.2|sse4_2", "x2apic", NULL, "popcnt",
+    NULL, NULL, NULL, NULL,
+    NULL, NULL, NULL, "hypervisor",
 };
 static const char *ext2_feature_name[] = {
-    "fpu", "vme", "de", "pse", "tsc", "msr", "pae", "mce",
-    "cx8" /* AMD CMPXCHG8B */, "apic", NULL, "syscall", "mtrr", "pge", "mca", "cmov",
-    "pat", "pse36", NULL, NULL /* Linux mp */, "nx" /* Intel xd */, NULL, "mmxext", "mmx",
-    "fxsr", "fxsr_opt" /* AMD ffxsr */, "pdpe1gb" /* AMD Page1GB */, "rdtscp", NULL, "lm" /* Intel 64 */, "3dnowext", "3dnow",
+    "fpu", "vme", "de", "pse",
+    "tsc", "msr", "pae", "mce",
+    "cx8" /* AMD CMPXCHG8B */, "apic", NULL, "syscall",
+    "mtrr", "pge", "mca", "cmov",
+    "pat", "pse36", NULL, NULL /* Linux mp */,
+    "nx" /* Intel xd */, NULL, "mmxext", "mmx",
+    "fxsr", "fxsr_opt" /* AMD ffxsr */, "pdpe1gb" /* AMD Page1GB */, "rdtscp",
+    NULL, "lm" /* Intel 64 */, "3dnowext", "3dnow",
 };
 static const char *ext3_feature_name[] = {
-    "lahf_lm" /* AMD LahfSahf */, "cmp_legacy", "svm", "extapic" /* AMD ExtApicSpace */, "cr8legacy" /* AMD AltMovCr8 */, "abm", "sse4a", "misalignsse",
-    "3dnowprefetch", "osvw", NULL /* Linux ibs */, NULL, "skinit", "wdt", NULL, NULL,
-    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+    "lahf_lm" /* AMD LahfSahf */, "cmp_legacy", "svm", "extapic" /* AMD ExtApicSpace */,
+    "cr8legacy" /* AMD AltMovCr8 */, "abm", "sse4a", "misalignsse",
+    "3dnowprefetch", "osvw", NULL /* Linux ibs */, NULL,
+    "skinit", "wdt", NULL, NULL,
+    NULL, NULL, NULL, NULL,
+    NULL, NULL, NULL, NULL,
+    NULL, NULL, NULL, NULL,
+    NULL, NULL, NULL, NULL,
 };
 
 static const char *kvm_feature_name[] = {
@@ -65,47 +84,99 @@ static const char *kvm_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;
+int enforce_cpuid = 0;
+
+static void host_cpuid(uint32_t function, uint32_t count, uint32_t *eax,
+                       uint32_t *ebx, uint32_t *ecx, uint32_t *edx);
+
+#define iswhite(c) ((c) && ((c) <= ' ' || '~' < (c)))
+
+/* general substring compare of *[s1..e1) and *[s2..e2).  sx is start of
+ * a substring.  ex if !NULL points to the first char after a substring,
+ * otherwise the string is assumed to sized by a terminating nul.
+ * Return lexical ordering of *s1:*s2.
+ */
+static int sstrcmp(const char *s1, const char *e1, const char *s2,
+    const char *e2)
+{
+    for (;;) {
+        if (!*s1 || !*s2 || *s1 != *s2)
+            return (*s1 - *s2);
+        ++s1, ++s2;
+        if (s1 == e1 && s2 == e2)
+            return (0);
+        else if (s1 == e1)
+            return (*s2);
+        else if (s2 == e2)
+            return (*s1);
+    }
+}
+
+/* compare *[s..e) to *altstr.  *altstr may be a simple string or multiple
+ * '|' delimited (possibly empty) strings in which case search for a match
+ * within the alternatives proceeds left to right.  Return 0 for success,
+ * non-zero otherwise.
+ */
+static int altcmp(const char *s, const char *e, const char *altstr)
+{
+    const char *p, *q;
+
+    for (q = p = altstr; ; ) {
+        while (*p && *p != '|')
+            ++p;
+        if ((q == p && !*s) || (q != p && !sstrcmp(s, e, q, p)))
+            return (0);
+        if (!*p)
+            return (1);
+        else
+            q = ++p;
+    }
+}
+
+/* search featureset for flag *[s..e), if found set corresponding bit in
+ * *pval and return success, otherwise return zero
+ */
+static int lookup_feature(uint32_t *pval, const char *s, const char *e,
+    const char **featureset)
+{
+    uint32_t mask;
+    const char **ppc;
+
+    for (mask = 1, ppc = featureset; mask; mask <<= 1, ++ppc)
+        if (*ppc && !altcmp(s, e, *ppc)) {
+            *pval |= mask;
+            break;
+        }
+    return (mask ? 1 : 0);
+}
+
 static void add_flagname_to_bitmaps(const char *flagname, uint32_t *features,
                                     uint32_t *ext_features,
                                     uint32_t *ext2_features,
                                     uint32_t *ext3_features,
                                     uint32_t *kvm_features)
 {
-    int i;
-    int found = 0;
-
-    for ( i = 0 ; i < 32 ; i++ )
-        if (feature_name[i] && !strcmp (flagname, feature_name[i])) {
-            *features |= 1 << i;
-            found = 1;
-        }
-    for ( i = 0 ; i < 32 ; i++ )
-        if (ext_feature_name[i] && !strcmp (flagname, ext_feature_name[i])) {
-            *ext_features |= 1 << i;
-            found = 1;
-        }
-    for ( i = 0 ; i < 32 ; i++ )
-        if (ext2_feature_name[i] && !strcmp (flagname, ext2_feature_name[i])) {
-            *ext2_features |= 1 << i;
-            found = 1;
-        }
-    for ( i = 0 ; i < 32 ; i++ )
-        if (ext3_feature_name[i] && !strcmp (flagname, ext3_feature_name[i])) {
-            *ext3_features |= 1 << i;
-            found = 1;
-        }
-    for ( i = 0 ; i < 32 ; i++ )
-        if (kvm_feature_name[i] && !strcmp (flagname, kvm_feature_name[i])) {
-            *kvm_features |= 1 << i;
-            found = 1;
-        }
-
-    if (!found) {
-        fprintf(stderr, "CPU feature %s not found\n", flagname);
-    }
+    if (!lookup_feature(features, flagname, NULL, feature_name) &&
+        !lookup_feature(ext_features, flagname, NULL, ext_feature_name) &&
+        !lookup_feature(ext2_features, flagname, NULL, ext2_feature_name) &&
+        !lookup_feature(ext3_features, flagname, NULL, ext3_feature_name) &&
+        !lookup_feature(kvm_features, flagname, NULL, kvm_feature_name))
+            fprintf(stderr, "CPU feature %s not found\n", flagname);
 }
 
 typedef struct x86_def_t {
+    struct x86_def_t *next;
     const char *name;
     uint32_t level;
     uint32_t vendor1, vendor2, vendor3;
@@ -116,6 +187,7 @@ typedef struct x86_def_t {
     uint32_t xlevel;
     char model_id[48];
     int vendor_override;
+    uint32_t flags;
 } x86_def_t;
 
 #define I486_FEATURES (CPUID_FP87 | CPUID_VME | CPUID_PSE)
@@ -129,7 +201,14 @@ typedef struct x86_def_t {
           CPUID_MSR | CPUID_MCE | CPUID_CX8 | CPUID_PGE | CPUID_CMOV | \
           CPUID_PAT | CPUID_FXSR | CPUID_MMX | CPUID_SSE | CPUID_SSE2 | \
           CPUID_PAE | CPUID_SEP | CPUID_APIC)
-static x86_def_t x86_defs[] = {
+
+/* maintains list of cpu model definitions
+ */
+static x86_def_t *x86_defs = {NULL};
+
+/* built-in cpu model definitions (deprecated)
+ */
+static x86_def_t builtin_x86_defs[] = {
 #ifdef TARGET_X86_64
     {
         .name = "qemu64",
@@ -334,9 +413,6 @@ static x86_def_t x86_defs[] = {
     },
 };
 
-static void host_cpuid(uint32_t function, uint32_t count, uint32_t *eax,
-                               uint32_t *ebx, uint32_t *ecx, uint32_t *edx);
-
 static int cpu_x86_fill_model_id(char *str)
 {
     uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0;
@@ -382,6 +458,51 @@ 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;
@@ -393,13 +514,9 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *cpu_model)
     uint32_t minus_features = 0, minus_ext_features = 0, minus_ext2_features = 0, minus_ext3_features = 0, minus_kvm_features = 0;
     uint32_t numvalue;
 
-    def = NULL;
-    for (i = 0; i < ARRAY_SIZE(x86_defs); i++) {
-        if (strcmp(name, x86_defs[i].name) == 0) {
-            def = &x86_defs[i];
+    for (def = x86_defs; def; def = def->next)
+        if (!strcmp(name, def->name))
             break;
-        }
-    }
     if (kvm_enabled() && strcmp(name, "host") == 0) {
         cpu_x86_fill_host(x86_cpu_def);
     } else if (!def) {
@@ -488,6 +605,10 @@ 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 if (!strcmp(featurestr, "enforce")) {
+            check_cpuid = enforce_cpuid = 1;
         } else {
             fprintf(stderr, "feature string `%s' not in format (+feature|-feature|feature=xyz)\n", featurestr);
             goto error;
@@ -504,6 +625,10 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *cpu_model)
     x86_cpu_def->ext2_features &= ~minus_ext2_features;
     x86_cpu_def->ext3_features &= ~minus_ext3_features;
     x86_cpu_def->kvm_features &= ~minus_kvm_features;
+    if (check_cpuid) {
+        if (check_features_against_host(x86_cpu_def) && enforce_cpuid)
+            goto error;
+    }
     free(s);
     return 0;
 
@@ -512,12 +637,97 @@ error:
     return -1;
 }
 
-void x86_cpu_list (FILE *f, int (*cpu_fprintf)(FILE *f, const char *fmt, ...))
+/* generate a composite string into buf of all cpuid names in featureset
+ * selected by fbits.  indicate truncation at bufsize in the event of overflow.
+ * if flags, suppress names undefined in featureset.
+ */
+static void listflags(char *buf, int bufsize, uint32_t fbits,
+    const char **featureset, uint32_t flags)
 {
-    unsigned int i;
+    const char **p = &featureset[31];
+    char *q, *b, bit;
+    int nc;
+
+    b = 4 <= bufsize ? buf + (bufsize -= 3) - 1 : NULL;
+    *buf = '\0';
+    for (q = buf, bit = 31; fbits && bufsize; --p, fbits &= ~(1 << bit), --bit)
+        if (fbits & 1 << bit && (*p || !flags)) {
+            if (*p)
+                nc = snprintf(q, bufsize, "%s%s", q == buf ? "" : " ", *p);
+            else
+                nc = snprintf(q, bufsize, "%s[%d]", q == buf ? "" : " ", bit);
+            if (bufsize <= nc) {
+                if (b)
+                    sprintf(b, "...");
+                return;
+            }
+            q += nc;
+            bufsize -= nc;
+        }
+}
 
-    for (i = 0; i < ARRAY_SIZE(x86_defs); i++)
-        (*cpu_fprintf)(f, "x86 %16s\n", x86_defs[i].name);
+/* generate CPU information:
+ * -?        list model names
+ * -?model   list model names/IDs
+ * -?dump    output all model (x86_def_t) data
+ * -?cpuid   list all recognized cpuid flag names
+ */ 
+void x86_cpu_list (FILE *f, int (*cpu_fprintf)(FILE *f, const char *fmt, ...),
+                  const char *optarg)
+{
+    unsigned char model = !strcmp("?model", optarg);
+    unsigned char dump = !strcmp("?dump", optarg);
+    unsigned char cpuid = !strcmp("?cpuid", optarg);
+    x86_def_t *def;
+    char buf[256];
+
+    if (cpuid) {
+        (*cpu_fprintf)(f, "Recognized CPUID flags:\n");
+        listflags(buf, sizeof (buf), (uint32_t)~0, feature_name, 1);
+        (*cpu_fprintf)(f, "  f_edx: %s\n", buf);
+        listflags(buf, sizeof (buf), (uint32_t)~0, ext_feature_name, 1);
+        (*cpu_fprintf)(f, "  f_ecx: %s\n", buf);
+        listflags(buf, sizeof (buf), (uint32_t)~0, ext2_feature_name, 1);
+        (*cpu_fprintf)(f, "  extf_edx: %s\n", buf);
+        listflags(buf, sizeof (buf), (uint32_t)~0, ext3_feature_name, 1);
+        (*cpu_fprintf)(f, "  extf_ecx: %s\n", buf);
+        return;
+    }
+    for (def = x86_defs; def; def = def->next) {
+        snprintf(buf, sizeof (buf), def->flags ? "[%s]": "%s", def->name);
+        if (model || dump) {
+            (*cpu_fprintf)(f, "x86 %16s  %-48s\n", buf, def->model_id);
+        } else {
+            (*cpu_fprintf)(f, "x86 %16s\n", buf);
+        }
+        if (dump) {
+            memcpy(buf, &def->vendor1, sizeof (def->vendor1));
+            memcpy(buf + 4, &def->vendor2, sizeof (def->vendor2));
+            memcpy(buf + 8, &def->vendor3, sizeof (def->vendor3));
+            buf[12] = '\0';
+            (*cpu_fprintf)(f,
+                "  family %d model %d stepping %d level %d xlevel 0x%x"
+                " vendor \"%s\"\n",
+                def->family, def->model, def->stepping, def->level,
+                def->xlevel, buf);
+            listflags(buf, sizeof (buf), def->features, feature_name, 0);
+            (*cpu_fprintf)(f, "  feature_edx %08x (%s)\n", def->features,
+                buf);
+            listflags(buf, sizeof (buf), def->ext_features, ext_feature_name,
+                0);
+            (*cpu_fprintf)(f, "  feature_ecx %08x (%s)\n", def->ext_features,
+                buf);
+            listflags(buf, sizeof (buf), def->ext2_features, ext2_feature_name,
+                0);
+            (*cpu_fprintf)(f, "  extfeature_edx %08x (%s)\n",
+                def->ext2_features, buf);
+            listflags(buf, sizeof (buf), def->ext3_features, ext3_feature_name,
+                0);
+            (*cpu_fprintf)(f, "  extfeature_ecx %08x (%s)\n",
+                def->ext3_features, buf);
+            (*cpu_fprintf)(f, "\n");
+        }
+    }
 }
 
 static int cpu_x86_register (CPUX86State *env, const char *cpu_model)
@@ -566,6 +776,128 @@ static int cpu_x86_register (CPUX86State *env, const char *cpu_model)
     return 0;
 }
 
+#if !defined(CONFIG_LINUX_USER)
+/* copy vendor id string to 32 bit register, nul pad as needed
+ */
+static void cpyid(const char *s, uint32_t *id)
+{
+    char *d = (char *)id;
+    char i;
+
+    for (i = sizeof (*id); i--; )
+        *d++ = *s ? *s++ : '\0';
+}
+
+/* interpret radix and convert from string to arbitrary scalar,
+ * otherwise flag failure
+ */
+#define setscalar(pval, str, perr)                      \
+{                                                       \
+    char *pend;                                         \
+    unsigned long ul;                                   \
+                                                        \
+    ul = strtoul(str, &pend, 0);                        \
+    *str && !*pend ? (*pval = ul) : (*perr = 1);        \
+}
+
+/* map cpuid options to feature bits, otherwise return failure
+ * (option tags in *str are delimited by whitespace)
+ */
+static void setfeatures(uint32_t *pval, const char *str,
+    const char **featureset, int *perr)
+{
+    const char *p, *q;
+
+    for (q = p = str; *p || *q; q = p) {
+        while (iswhite(*p))
+            q = ++p; 
+        while (*p && !iswhite(*p))
+            ++p;
+        if (!*q && !*p)
+            return;
+        if (!lookup_feature(pval, q, p, featureset)) {
+            fprintf(stderr, "error: feature \"%.*s\" not available in set\n",
+                (int)(p - q), q);
+            *perr = 1;
+            return;
+        }
+    }
+}
+
+/* map config file options to x86_def_t form
+ */
+static int cpudef_setfield(const char *name, const char *str, void *opaque)
+{
+    x86_def_t *def = opaque;
+    int err = 0;
+
+    if (!strcmp(name, "name")) {
+        def->name = strdup(str);
+    } else if (!strcmp(name, "model_id")) {
+        strncpy(def->model_id, str, sizeof (def->model_id));
+    } else if (!strcmp(name, "level")) {
+        setscalar(&def->level, str, &err)
+    } else if (!strcmp(name, "vendor")) {
+        cpyid(&str[0], &def->vendor1);
+        cpyid(&str[4], &def->vendor2);
+        cpyid(&str[8], &def->vendor3);
+    } else if (!strcmp(name, "family")) {
+        setscalar(&def->family, str, &err)
+    } else if (!strcmp(name, "model")) {
+        setscalar(&def->model, str, &err)
+    } else if (!strcmp(name, "stepping")) {
+        setscalar(&def->stepping, str, &err)
+    } else if (!strcmp(name, "feature_edx")) {
+        setfeatures(&def->features, str, feature_name, &err);
+    } else if (!strcmp(name, "feature_ecx")) {
+        setfeatures(&def->ext_features, str, ext_feature_name, &err);
+    } else if (!strcmp(name, "extfeature_edx")) {
+        setfeatures(&def->ext2_features, str, ext2_feature_name, &err);
+    } else if (!strcmp(name, "extfeature_ecx")) {
+        setfeatures(&def->ext3_features, str, ext3_feature_name, &err);
+    } else if (!strcmp(name, "xlevel")) {
+        setscalar(&def->xlevel, str, &err)
+    } else {
+        fprintf(stderr, "error: unknown option [%s = %s]\n", name, str);
+        return (1);
+    }
+    if (err) {
+        fprintf(stderr, "error: bad option value [%s = %s]\n", name, str);
+        return (1);
+    }
+    return (0);
+}
+
+/* register config file entry as x86_def_t
+ */
+static int cpudef_register(QemuOpts *opts, void *opaque)
+{
+    x86_def_t *def = qemu_mallocz(sizeof (x86_def_t));
+
+    qemu_opt_foreach(opts, cpudef_setfield, def, 1);
+    def->next = x86_defs;
+    x86_defs = def;
+    return (0);
+}
+#endif	/* !CONFIG_LINUX_USER */
+
+/* register "cpudef" models defined in configuration file.  Here we first
+ * preload any built-in definitions
+ */
+void x86_cpudef_setup(void)
+{
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(builtin_x86_defs); ++i) {
+        builtin_x86_defs[i].next = x86_defs;
+        builtin_x86_defs[i].flags = 1;
+        x86_defs = &builtin_x86_defs[i];
+    }
+#if !defined(CONFIG_LINUX_USER)
+    qemu_opts_foreach(&qemu_cpudef_opts, cpudef_register, NULL, 0);
+#endif
+}
+
 /* NOTE: must be called outside the CPU execute loop */
 void cpu_reset(CPUX86State *env)
 {
diff --git a/vl.c b/vl.c
index 64d6f8bb2c..874246b617 100644
--- a/vl.c
+++ b/vl.c
@@ -4836,6 +4836,9 @@ int main(int argc, char **argv, char **envp)
             fclose(fp);
         }
     }
+#if defined(cpudef_setup)
+    cpudef_setup(); /* parse cpu definitions in target config file */
+#endif
 
     /* second pass of option parsing */
     optind = 1;
@@ -4869,8 +4872,10 @@ int main(int argc, char **argv, char **envp)
                 /* hw initialization will check this */
                 if (*optarg == '?') {
 /* XXX: implement xxx_cpu_list for targets that still miss it */
-#if defined(cpu_list)
-                    cpu_list(stdout, &fprintf);
+#if defined(cpu_list_id)
+                    cpu_list_id(stdout, &fprintf, optarg);
+#elif defined(cpu_list)
+                    cpu_list(stdout, &fprintf);	        /* deprecated */
 #endif
                     exit(0);
                 } else {