Patchwork Add cpu model configuration support.. (resend)

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Submitter john cooper
Date Feb. 1, 2010, 7:02 p.m.
Message ID <4B672535.5050303@redhat.com>
Download mbox | patch
Permalink /patch/44218/
State New
Headers show

Comments

john cooper - Feb. 1, 2010, 7:02 p.m.
[target-x86_64.conf was unintentionally omitted from the earlier patch]

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>
---
Andre Przywara - Feb. 2, 2010, 10:17 a.m.
john cooper wrote:

> [target-x86_64.conf was unintentionally omitted from the earlier patch]
> 
> 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.
 > ...
John,

first I would like to apologize for sending out my patch series although 
I know that it heavily conflicts with yours. Actually you beat me just 
by hours with yours, I had mine ready on Friday evening and just delayed 
the sending until Monday ;-)

Can you split up the patch into a series of smaller ones (maybe git add 
-i can help you here?). This version is a bit large for proper review 
and mixes fixes and feature additions. Additionally this would help to 
merge our both versions.

Regards,
Andre.
Andre Przywara - Feb. 2, 2010, 11:07 a.m.
John,

just two comments from skimming through the patch:

> diff --git a/sysconfigs/target/target-x86_64.conf b/sysconfigs/target/target-x86_64.conf
> new file mode 100644
> index 0000000..43ad282
> --- /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"
Wouldn't it be much more user friendly to merge them all into one 
string? Just from the feature names it is quite obscure to guess which 
flag belongs into which string (especially since we lack the EXTn_ 
prefix we had in helper.c). I haven't tried it, but the parsing code 
looks like this shouldn't be too hard.
To avoid overlong lines one could think about a += operator.

> @@ -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",

I would just drop all definitions here except qemu{32,64} and 
kvm{32,64}. The other models should be described in the config file.

Regards,
Andre.
john cooper - Feb. 2, 2010, 7:34 p.m.
Andre Przywara wrote:

>> +[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"
> Wouldn't it be much more user friendly to merge them all into one
> string? Just from the feature names it is quite obscure to guess which
> flag belongs into which string (especially since we lack the EXTn_
> prefix we had in helper.c). I haven't tried it, but the parsing code
> looks like this shouldn't be too hard.
> To avoid overlong lines one could think about a += operator.

That's true.  Although I expect setup of a cpu model to
be a rather infrequent occurrence by the expert (+/-)
user so the above didn't strike me as a significant issue.
Also "-cpu ?cpuid" dumps out the entire motley crew of
flags relative to each grouping for reference.

That said the current config file syntax seems rather
rigid and I think your suggestion makes sense.  I avoided
modifying the parser at this point just in the interest of
minimizing the sprawl of this patch.

> I would just drop all definitions here except qemu{32,64} and
> kvm{32,64}. The other models should be described in the config file.

That's the goal but I wanted to leave an interim firewall
of sorts.  If the target-x86_64.conf isn't installed for
whatever reason, qemu still can fall back to the internal
definitions.  Even here it isn't strictly necessary to
remove an internal def as it can be redefined in the
config file which will override the internal version.
In general -cpu "?model" will indicate internal vs.
externally defined models by enclosing internal model names
in brackets:

    :
x86       Opteron_G3  AMD Opteron 23xx (Gen 3 Class Opteron)
    :
x86         [athlon]  QEMU Virtual CPU version 0.12.50
    :

It also seems worth dropping a hint to the user in the case qemu
fails to find a target config file rather than leaving them to
puzzle out why an external model has gone missing.

Thanks for the feedback.

-john
Anthony Liguori - Feb. 10, 2010, 8 p.m.
On 02/01/2010 01:02 PM, john cooper wrote:
> [target-x86_64.conf was unintentionally omitted from the earlier patch]
>
> 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
>    

This breaks the arm-softmmu build.

Regards,

Anthony Liguori

> 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>
> ---
>
> diff --git a/Makefile b/Makefile
> index 3848627..b7fa6ef 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/qemu-config.c b/qemu-config.c
> index c3203c8..246fae6 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 dd89ae4..b335c42 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 0000000..43ad282
> --- /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 216b00e..c1a5256 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 cpudef_setup(void);
> +
>   int cpu_get_pic_interrupt(CPUX86State *s);
>   /* MSDOS compatibility mode FPU exception support */
>   void cpu_set_ferr(CPUX86State *s);
> @@ -876,7 +878,7 @@ 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 CPU_SAVE_VERSION 11
>
> diff --git a/target-i386/helper.c b/target-i386/helper.c
> index 70762bb..37dd2c6 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 +776,124 @@ static int cpu_x86_register (CPUX86State *env, const char *cpu_model)
>       return 0;
>   }
>
> +/* 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);
> +}
> +
> +/* register "cpudef" models defined in configuration file after preloading
> + * built-in definitions
> + */
> +void 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];
> +    }
> +    qemu_opts_foreach(&qemu_cpudef_opts, cpudef_register, NULL, 0);
> +}
> +
>   /* NOTE: must be called outside the CPU execute loop */
>   void cpu_reset(CPUX86State *env)
>   {
> diff --git a/vl.c b/vl.c
> index 6f1e1ab..d6cd62c 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -4851,6 +4851,7 @@ int main(int argc, char **argv, char **envp)
>               fclose(fp);
>           }
>       }
> +    cpudef_setup();
>
>       /* second pass of option parsing */
>       optind = 1;
> @@ -4884,8 +4885,10 @@ 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 {
>
john cooper - Feb. 14, 2010, 6:52 a.m.
Anthony Liguori wrote:
> On 02/01/2010 01:02 PM, john cooper wrote:
>> [target-x86_64.conf was unintentionally omitted from the earlier patch]
>>
>> 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
>>    
> 
> This breaks the arm-softmmu build.

Ugh, does indeed as well as a few other builds.
Updated patch follows.

-john

Patch

diff --git a/Makefile b/Makefile
index 3848627..b7fa6ef 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/qemu-config.c b/qemu-config.c
index c3203c8..246fae6 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 dd89ae4..b335c42 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 0000000..43ad282
--- /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 216b00e..c1a5256 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 cpudef_setup(void);
+
 int cpu_get_pic_interrupt(CPUX86State *s);
 /* MSDOS compatibility mode FPU exception support */
 void cpu_set_ferr(CPUX86State *s);
@@ -876,7 +878,7 @@  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 CPU_SAVE_VERSION 11
 
diff --git a/target-i386/helper.c b/target-i386/helper.c
index 70762bb..37dd2c6 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 +776,124 @@  static int cpu_x86_register (CPUX86State *env, const char *cpu_model)
     return 0;
 }
 
+/* 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);
+}
+
+/* register "cpudef" models defined in configuration file after preloading
+ * built-in definitions
+ */
+void 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];
+    }
+    qemu_opts_foreach(&qemu_cpudef_opts, cpudef_register, NULL, 0);
+}
+
 /* NOTE: must be called outside the CPU execute loop */
 void cpu_reset(CPUX86State *env)
 {
diff --git a/vl.c b/vl.c
index 6f1e1ab..d6cd62c 100644
--- a/vl.c
+++ b/vl.c
@@ -4851,6 +4851,7 @@  int main(int argc, char **argv, char **envp)
             fclose(fp);
         }
     }
+    cpudef_setup();
 
     /* second pass of option parsing */
     optind = 1;
@@ -4884,8 +4885,10 @@  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 {