Patchwork Add definitions for current cpu models..

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Submitter john cooper
Date Dec. 21, 2009, 6:46 a.m.
Message ID <4B2F19CC.5020808@redhat.com>
Download mbox | patch
Permalink /patch/41518/
State New
Headers show

Comments

john cooper - Dec. 21, 2009, 6:46 a.m.
This adds definitions for contemporary processors
which may be selected via -cpu <model>, as an
alternative to the existing use of -cpu qemu64
augmented with a series of feature flags.

The primary motivation was determination of a
least common denominator within a given processor
class for simplification of 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. 

A cpu feature 'check' option is also added which
warns when feature flags (either implicit in a cpu
model or explicit on the command line) would have
otherwise been quietly disabled for a guest.

This patch was tested relative to qemu-kvm.git.

Signed-off-by: john cooper <john.cooper@redhat.com>
---
Marcelo Tosatti - Dec. 24, 2009, 1:05 p.m.
On Mon, Dec 21, 2009 at 01:46:36AM -0500, john cooper wrote:
> This adds definitions for contemporary processors
> which may be selected via -cpu <model>, as an
> alternative to the existing use of -cpu qemu64
> augmented with a series of feature flags.
> 
> The primary motivation was determination of a
> least common denominator within a given processor
> class for simplification of 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. 
> 
> A cpu feature 'check' option is also added which
> warns when feature flags (either implicit in a cpu
> model or explicit on the command line) would have
> otherwise been quietly disabled for a guest.
> 
> This patch was tested relative to qemu-kvm.git.
> 
> Signed-off-by: john cooper <john.cooper@redhat.com>
> ---
> 
> diff --git a/target-i386/helper.c b/target-i386/helper.c
> index 9a50da6..a706cae 100644
> --- a/target-i386/helper.c
> +++ b/target-i386/helper.c
> @@ -44,7 +44,7 @@ static const char *feature_name[] = {
>  static const char *ext_feature_name[] = {
>      "pni" /* Intel,AMD sse3 */, NULL, NULL, "monitor", "ds_cpl", "vmx", NULL /* Linux smx */, "est",
>      "tm2", "ssse3", "cid", NULL, NULL, "cx16", "xtpr", NULL,
> -    NULL, NULL, "dca", NULL, NULL, "x2apic", NULL, "popcnt",
> +    NULL, NULL, "dca", "sse4.1", "sse4.2", "x2apic", NULL, "popcnt",
>      NULL, NULL, NULL, NULL, NULL, NULL, NULL, "hypervisor",
>  };

Separate patch?

>  static const char *ext2_feature_name[] = {
> @@ -60,6 +60,18 @@ static const char *ext3_feature_name[] = {
>      NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
>  };
>  
> +/* collects per-function cpuid data
> + */
> +typedef struct model_features_t {
> +    uint32_t *guest_feat;
> +    uint32_t *host_feat;
> +    uint32_t check_feat;
> +    const char **flag_names;
> +    uint32_t cpuid;
> +    } model_features_t;
> +
> +int check_cpuid = 0;
> +
>  static void add_flagname_to_bitmaps(const char *flagname, uint32_t *features,
>                                      uint32_t *ext_features,
>                                      uint32_t *ext2_features,
> @@ -171,6 +183,139 @@ static x86_def_t x86_defs[] = {
>          .model_id = "AMD Phenom(tm) 9550 Quad-Core Processor"
>      },
>      {
> +        .name = "Merom",
> +        .level = 2,
> +        .vendor1 = CPUID_VENDOR_INTEL_1,
> +        .vendor2 = CPUID_VENDOR_INTEL_2,
> +        .vendor3 = CPUID_VENDOR_INTEL_3,
> +        .family = 6,	/* P6 */
> +        .model = 2,
> +        .stepping = 3,
> +        .features = PPRO_FEATURES | 
> +        /* these features are needed for Win64 and aren't fully implemented */
> +            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
> +        /* this feature is needed for Solaris and isn't fully implemented */
> +            CPUID_PSE36,
> +        .ext_features = CPUID_EXT_SSE3,		/* from qemu64 */
> +        .ext2_features = (PPRO_FEATURES & 0x0183F3FF) | 
> +            CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
> +        .ext3_features = CPUID_EXT3_SVM,	/* from qemu64 */
> +        .xlevel = 0x8000000A,
> +        .model_id = "Intel Merom Core 2",
> +    },
> +    {
> +        .name = "Penryn",
> +        .level = 2,
> +        .vendor1 = CPUID_VENDOR_INTEL_1,
> +        .vendor2 = CPUID_VENDOR_INTEL_2,
> +        .vendor3 = CPUID_VENDOR_INTEL_3,
> +        .family = 6,	/* P6 */
> +        .model = 2,
> +        .stepping = 3,
> +        .features = PPRO_FEATURES | 
> +        /* these features are needed for Win64 and aren't fully implemented */
> +            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
> +        /* this feature is needed for Solaris and isn't fully implemented */
> +            CPUID_PSE36,
> +        .ext_features = CPUID_EXT_SSE3 |
> +            CPUID_EXT_CX16 | CPUID_EXT_SSSE3 | CPUID_EXT_SSE41,
> +        .ext2_features = (PPRO_FEATURES & 0x0183F3FF) | 
> +            CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
> +        .ext3_features = CPUID_EXT3_SVM,
> +        .xlevel = 0x8000000A,
> +        .model_id = "Intel Penryn Core 2",
> +    },
> +    {
> +        .name = "Nehalem",
> +        .level = 2,
> +        .vendor1 = CPUID_VENDOR_INTEL_1,
> +        .vendor2 = CPUID_VENDOR_INTEL_2,
> +        .vendor3 = CPUID_VENDOR_INTEL_3,
> +        .family = 6,	/* P6 */
> +        .model = 2,
> +        .stepping = 3,
> +        .features = PPRO_FEATURES | 
> +        /* these features are needed for Win64 and aren't fully implemented */
> +            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
> +        /* this feature is needed for Solaris and isn't fully implemented */
> +            CPUID_PSE36,
> +        .ext_features = CPUID_EXT_SSE3 |
> +            CPUID_EXT_CX16 | CPUID_EXT_SSSE3 | CPUID_EXT_SSE41 |
> +            CPUID_EXT_SSE42 | CPUID_EXT_POPCNT,
> +        .ext2_features = (PPRO_FEATURES & 0x0183F3FF) | 
> +            CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
> +        .ext3_features = CPUID_EXT3_SVM,
> +        .xlevel = 0x8000000A,
> +        .model_id = "Intel Nehalem Core i7",
> +    },
> +    {
> +        .name = "Opteron_G1",
> +        .level = 5,
> +        .vendor1 = CPUID_VENDOR_INTEL_1,
> +        .vendor2 = CPUID_VENDOR_INTEL_2,
> +        .vendor3 = CPUID_VENDOR_INTEL_3,
> +        .family = 15,
> +        .model = 6,
> +        .stepping = 1,
> +        .features = PPRO_FEATURES | 
> +        /* these features are needed for Win64 and aren't fully implemented */
> +            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
> +        /* this feature is needed for Solaris and isn't fully implemented */
> +            CPUID_PSE36,
> +        .ext_features = CPUID_EXT_SSE3 | CPUID_EXT_MONITOR,
> +        .ext2_features = (PPRO_FEATURES & 0x0183F3FF) | 
> +            CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
> +        .ext3_features = CPUID_EXT3_SVM,
> +        .xlevel = 0x80000008,
> +        .model_id = "AMD Opteron G1",
> +    },
> +    {
> +        .name = "Opteron_G2",
> +        .level = 5,
> +        .vendor1 = CPUID_VENDOR_INTEL_1,
> +        .vendor2 = CPUID_VENDOR_INTEL_2,
> +        .vendor3 = CPUID_VENDOR_INTEL_3,

Silly question: why a CPU named "Opteron_G2" uses intel vendor id's?

> +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;
> +}

Deserves a separate patch, too.
Avi Kivity - Dec. 24, 2009, 1:45 p.m.
On 12/21/2009 08:46 AM, john cooper wrote:
> This adds definitions for contemporary processors
> which may be selected via -cpu<model>, as an
> alternative to the existing use of -cpu qemu64
> augmented with a series of feature flags.
>
> The primary motivation was determination of a
> least common denominator within a given processor
> class for simplification of 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.
>
> A cpu feature 'check' option is also added which
> warns when feature flags (either implicit in a cpu
> model or explicit on the command line) would have
> otherwise been quietly disabled for a guest.
>
> This patch was tested relative to qemu-kvm.git.
>    


Nothing kvm-specific in there, yes?  If so, it should go though qemu.git.
Jamie Lokier - Dec. 31, 2009, 3:13 a.m.
john cooper wrote:
>      {
> +        .name = "Merom",
> +        .level = 2,
> +        .vendor1 = CPUID_VENDOR_INTEL_1,
> +        .vendor2 = CPUID_VENDOR_INTEL_2,
> +        .vendor3 = CPUID_VENDOR_INTEL_3,
> +        .family = 6,	/* P6 */
> +        .model = 2,
> +        .stepping = 3,
> +        .features = PPRO_FEATURES | 
> +        /* these features are needed for Win64 and aren't fully implemented */
> +            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
> +        /* this feature is needed for Solaris and isn't fully implemented */
> +            CPUID_PSE36,
> +        .ext_features = CPUID_EXT_SSE3,		/* from qemu64 */

Isn't SSE3 a generic feature on these Intel CPUs, so this comment is unnecessary?
Or is SSE3 not present on a real Merom?  If so, wouldn't it be better to omit it?

> +        .ext2_features = (PPRO_FEATURES & 0x0183F3FF) | 

Could we have a meaningful name for the magic number, please?
Maybe even a:

   #define PPRO_EXT2_FEATURES (PPRO_FEATURES & PPRO_EXT2_MASK)
   #define PPRO_EXT2_MASK     (CPUID_... | CPUID_... | ...) /* Fill in. */

> +            CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
> +        .ext3_features = CPUID_EXT3_SVM,	/* from qemu64 */
> +        .xlevel = 0x8000000A,
> +        .model_id = "Intel Merom Core 2",
> +    },

Does this mean requesting an Intel Merom will give the guest AMD's SVM
capability?  That's handy for virtualisation, but not an accurate CPU
model.  It seems inappropriate to name it "Merom", with model_id
"Intel Merom Core 2", if it's adding extra qemu-specific capabilities.

I would think few guests are likely to need the nested-SVM capability,
so it could be omitted when "Merom" is requested, and added as an
additional feature on request from the command line, just like other
cpuid features can be added.

> +    {
> +        .name = "Penryn",
> +        .level = 2,
> +        .vendor1 = CPUID_VENDOR_INTEL_1,
> +        .vendor2 = CPUID_VENDOR_INTEL_2,
> +        .vendor3 = CPUID_VENDOR_INTEL_3,
> +        .family = 6,	/* P6 */
> +        .model = 2,
> +        .stepping = 3,
> +        .features = PPRO_FEATURES | 
> +        /* these features are needed for Win64 and aren't fully implemented */
> +            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
> +        /* this feature is needed for Solaris and isn't fully implemented */
> +            CPUID_PSE36,
> +        .ext_features = CPUID_EXT_SSE3 |
> +            CPUID_EXT_CX16 | CPUID_EXT_SSSE3 | CPUID_EXT_SSE41,
> +        .ext2_features = (PPRO_FEATURES & 0x0183F3FF) | 
> +            CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
> +        .ext3_features = CPUID_EXT3_SVM,
> +        .xlevel = 0x8000000A,
> +        .model_id = "Intel Penryn Core 2",
> +    },

Same comments as above for Merom about SVM and the PPRO_FEATURES mask.

You don't include the "from qemu64" comments this time.  Is there a reason?

> +    {
> +        .name = "Nehalem",
> +        .level = 2,
> +        .vendor1 = CPUID_VENDOR_INTEL_1,
> +        .vendor2 = CPUID_VENDOR_INTEL_2,
> +        .vendor3 = CPUID_VENDOR_INTEL_3,
> +        .family = 6,	/* P6 */
> +        .model = 2,
> +        .stepping = 3,
> +        .features = PPRO_FEATURES | 
> +        /* these features are needed for Win64 and aren't fully implemented */
> +            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
> +        /* this feature is needed for Solaris and isn't fully implemented */
> +            CPUID_PSE36,
> +        .ext_features = CPUID_EXT_SSE3 |
> +            CPUID_EXT_CX16 | CPUID_EXT_SSSE3 | CPUID_EXT_SSE41 |
> +            CPUID_EXT_SSE42 | CPUID_EXT_POPCNT,
> +        .ext2_features = (PPRO_FEATURES & 0x0183F3FF) | 
> +            CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
> +        .ext3_features = CPUID_EXT3_SVM,
> +        .xlevel = 0x8000000A,
> +        .model_id = "Intel Nehalem Core i7",
> +    },

Same as previous.

> +    {
> +        .name = "Opteron_G1",
> +        .level = 5,
> +        .vendor1 = CPUID_VENDOR_INTEL_1,
> +        .vendor2 = CPUID_VENDOR_INTEL_2,
> +        .vendor3 = CPUID_VENDOR_INTEL_3,

Someone else has already enquired - why Intel vendor id?

> +        .family = 15,
> +        .model = 6,
> +        .stepping = 1,
> +        .features = PPRO_FEATURES | 
> +        /* these features are needed for Win64 and aren't fully implemented */
> +            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
> +        /* this feature is needed for Solaris and isn't fully implemented */
> +            CPUID_PSE36,
> +        .ext_features = CPUID_EXT_SSE3 | CPUID_EXT_MONITOR,
> +        .ext2_features = (PPRO_FEATURES & 0x0183F3FF) | 
> +            CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
> +        .ext3_features = CPUID_EXT3_SVM,
> +        .xlevel = 0x80000008,
> +        .model_id = "AMD Opteron G1",
> +    },

Why do the AMD models have CPUID_EXT_MONITOR but the Intel ones don't.
Is it correct for the CPU models?  Even a lowly 32-bit Intel Core has MONITOR.
Is it omitted for performance?  In that case shouldn't it be omitted for AMD too?

> +    {
> +        .name = "Opteron_G2",
> +        .level = 5,
> +        .vendor1 = CPUID_VENDOR_INTEL_1,
> +        .vendor2 = CPUID_VENDOR_INTEL_2,
> +        .vendor3 = CPUID_VENDOR_INTEL_3,
> +        .family = 15,
> +        .model = 6,
> +        .stepping = 1,
> +        .features = PPRO_FEATURES | 
> +        /* these features are needed for Win64 and aren't fully implemented */
> +            CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
> +        /* this feature is needed for Solaris and isn't fully implemented */
> +            CPUID_PSE36 | CPUID_EXT_CX16,

Solaris comment can use plurals here, like Win64 :-)

> +        .model_id = "AMD Opteron G3",
> +    },
> +        /* this feature is needed for Solaris and isn't fully implemented */
> +    {
The above Solaris comment seems out of place.

>          .name = "core2duo",

The new name style is clearly different from the old name style,
"Merom" and "Opteron_G3" vs "core2duo".  It's a bit untidy.

I'm thinking The names "Merom", "Penryn" and so on might be better as
"Intel Meron", "Intel Penryn" and so on (or perhaps with underscores),
and changing "core2duo" to "Intel Core 2 Duo" and so on.

>          .level = 10,
>          .family = 6,
> @@ -319,7 +464,7 @@ static x86_def_t x86_defs[] = {
>          /* Missing: .ext3_features = CPUID_EXT3_LAHF_LM */
>          .xlevel = 0x8000000A,
>          .model_id = "Intel(R) Atom(TM) CPU N270   @ 1.60GHz",
> -    },
> +    }
>  };

What does qemu coding style say about comma after the last element in a list?
(Not serious :-)

> +/* 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.
> + */

With the recent KVM special handling of the SYSCALL feature, so that
Intel 64-bit hosts can run 64-bit guest kernels with 32-bit userspace
without triggering SYSCALL emulation (and working on older host kernels),
how does the feature masking work out for the SYSCALL feature with "check"?

And general comments:

Thanks for adding the CPU models.  You said they've been checked by
Intel and AMD, but as you can tell from my comments, it's hard to tell
(without consulting processor manuals) if they are accurate
descriptions of real CPU models, or approximations.  What's the intention?

They are all 64-bit models.  Any plans to add contemporary 32-bit
models, or is the existing list of those complete enough already?

Thanks,
-- Jamie
john cooper - Jan. 5, 2010, 6:06 a.m.
Marcelo Tosatti wrote:
> On Mon, Dec 21, 2009 at 01:46:36AM -0500, john cooper wrote:
>> +    {
>> +        .name = "Opteron_G2",
>> +        .level = 5,
>> +        .vendor1 = CPUID_VENDOR_INTEL_1,
>> +        .vendor2 = CPUID_VENDOR_INTEL_2,
>> +        .vendor3 = CPUID_VENDOR_INTEL_3,
> 
> Silly question: why a CPU named "Opteron_G2" uses intel vendor id's?

The feedback I had from AMD indicated using the Intel
strings for a family 15 cpu resulted in the least
amount of guest confusion.  The upstream kvm64 model
does similarly.

Sorry for my late response here which was preempted
by the intervening holiday.

-john

Patch

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