diff mbox series

[for-4.19,v2] tools/xen-cpuid: switch to use cpu-policy defined names

Message ID 20240502114922.94288-1-roger.pau@citrix.com (mailing list archive)
State Superseded
Headers show
Series [for-4.19,v2] tools/xen-cpuid: switch to use cpu-policy defined names | expand

Commit Message

Roger Pau Monne May 2, 2024, 11:49 a.m. UTC
Like it was done recently for libxl, switch to using the auto-generated feature
names by the processing of cpufeatureset.h, this allows removing the open-coded
feature names, and unifies the feature naming with libxl and the hypervisor.

Introduce a newly auto-generated array that contains the feature names indexed
at featureset bit position, otherwise using the existing INIT_FEATURE_NAMES
would require iterating over the array elements until a match with the expected
bit position is found.

Note that leaf names need to be kept, as the current auto-generated data
doesn't contain the leaf names.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
Changes since v1:
 - Modify gen-cpuid.py to generate an array of strings with the feature names.
 - Introduce and use __maybe_unused.
---
 tools/include/xen-tools/common-macros.h |   4 +
 tools/misc/xen-cpuid.c                  | 320 +++---------------------
 xen/tools/gen-cpuid.py                  |  26 ++
 3 files changed, 68 insertions(+), 282 deletions(-)

Comments

Jan Beulich May 2, 2024, 1:16 p.m. UTC | #1
On 02.05.2024 13:49, Roger Pau Monne wrote:
> Like it was done recently for libxl, switch to using the auto-generated feature
> names by the processing of cpufeatureset.h, this allows removing the open-coded
> feature names, and unifies the feature naming with libxl and the hypervisor.
> 
> Introduce a newly auto-generated array that contains the feature names indexed
> at featureset bit position, otherwise using the existing INIT_FEATURE_NAMES
> would require iterating over the array elements until a match with the expected
> bit position is found.
> 
> Note that leaf names need to be kept, as the current auto-generated data
> doesn't contain the leaf names.
> 
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>

Reviewed-by: Jan Beulich <jbeulich@suse.com>
except that ...

> --- a/xen/tools/gen-cpuid.py
> +++ b/xen/tools/gen-cpuid.py
> @@ -475,6 +475,32 @@ def write_results(state):
>      state.output.write(
>  """}
>  
> +""")
> +
> +    state.output.write(
> +"""
> +#define INIT_FEATURE_NAME_ARRAY { \\
> +""")
> +
> +    try:
> +        _tmp = state.names.iteritems()
> +    except AttributeError:
> +        _tmp = state.names.items()

... can't figure what this try/except is needed for. Hopefully someone with
better Python foo than mine can take a look.

Jan
Roger Pau Monne May 2, 2024, 2:34 p.m. UTC | #2
On Thu, May 02, 2024 at 03:16:54PM +0200, Jan Beulich wrote:
> On 02.05.2024 13:49, Roger Pau Monne wrote:
> > Like it was done recently for libxl, switch to using the auto-generated feature
> > names by the processing of cpufeatureset.h, this allows removing the open-coded
> > feature names, and unifies the feature naming with libxl and the hypervisor.
> > 
> > Introduce a newly auto-generated array that contains the feature names indexed
> > at featureset bit position, otherwise using the existing INIT_FEATURE_NAMES
> > would require iterating over the array elements until a match with the expected
> > bit position is found.
> > 
> > Note that leaf names need to be kept, as the current auto-generated data
> > doesn't contain the leaf names.
> > 
> > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> 
> Reviewed-by: Jan Beulich <jbeulich@suse.com>
> except that ...

Thanks.

> 
> > --- a/xen/tools/gen-cpuid.py
> > +++ b/xen/tools/gen-cpuid.py
> > @@ -475,6 +475,32 @@ def write_results(state):
> >      state.output.write(
> >  """}
> >  
> > +""")
> > +
> > +    state.output.write(
> > +"""
> > +#define INIT_FEATURE_NAME_ARRAY { \\
> > +""")
> > +
> > +    try:
> > +        _tmp = state.names.iteritems()
> > +    except AttributeError:
> > +        _tmp = state.names.items()
> 
> ... can't figure what this try/except is needed for. Hopefully someone with
> better Python foo than mine can take a look.

If I understood this correctly (which I might have not, I know very
little Python), iteritems() method was removed in Python 3, and what
used to be iteritems() in Python 2 is items() on Python 3.

Regards, Roger.
Roger Pau Monne May 9, 2024, 12:13 p.m. UTC | #3
On Thu, May 02, 2024 at 03:16:54PM +0200, Jan Beulich wrote:
> On 02.05.2024 13:49, Roger Pau Monne wrote:
> > Like it was done recently for libxl, switch to using the auto-generated feature
> > names by the processing of cpufeatureset.h, this allows removing the open-coded
> > feature names, and unifies the feature naming with libxl and the hypervisor.
> > 
> > Introduce a newly auto-generated array that contains the feature names indexed
> > at featureset bit position, otherwise using the existing INIT_FEATURE_NAMES
> > would require iterating over the array elements until a match with the expected
> > bit position is found.
> > 
> > Note that leaf names need to be kept, as the current auto-generated data
> > doesn't contain the leaf names.
> > 
> > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> 
> Reviewed-by: Jan Beulich <jbeulich@suse.com>

Oleksii, now that Jan has provided a Reviewed-by, can you provide a
release-ack for this to go in?

Thanks, Roger.
Andrew Cooper May 10, 2024, 6:08 p.m. UTC | #4
On 02/05/2024 12:49 pm, Roger Pau Monne wrote:
> diff --git a/tools/include/xen-tools/common-macros.h b/tools/include/xen-tools/common-macros.h
> index 07aed92684b5..3e6a66080a4f 100644
> --- a/tools/include/xen-tools/common-macros.h
> +++ b/tools/include/xen-tools/common-macros.h
> @@ -83,6 +83,10 @@
>  #define __packed __attribute__((__packed__))
>  #endif
>  
> +#ifndef __maybe_unused
> +# define __maybe_unused __attribute__((__unused__))
> +#endif
> +
>  #define container_of(ptr, type, member) ({              \
>      typeof(((type *)0)->member) *mptr__ = (ptr);        \
>      (type *)((char *)mptr__ - offsetof(type, member));  \

This hunk needs a matching:

diff --git a/tools/tests/x86_emulator/x86-emulate.h
b/tools/tests/x86_emulator/x86-emulate.h
index 8f8accfe3e70..a702c9faf207 100644
--- a/tools/tests/x86_emulator/x86-emulate.h
+++ b/tools/tests/x86_emulator/x86-emulate.h
@@ -50,7 +50,6 @@
 #define this_cpu(var) per_cpu_##var
 
 #define __init
-#define __maybe_unused __attribute__((__unused__))
 
 #define likely(x)   __builtin_expect(!!(x), true)
 #define unlikely(x) __builtin_expect(!!(x), false)

~Andrew
Oleksii Kurochko May 14, 2024, 9:15 a.m. UTC | #5
On Thu, 2024-05-09 at 14:13 +0200, Roger Pau Monné wrote:
> On Thu, May 02, 2024 at 03:16:54PM +0200, Jan Beulich wrote:
> > On 02.05.2024 13:49, Roger Pau Monne wrote:
> > > Like it was done recently for libxl, switch to using the auto-
> > > generated feature
> > > names by the processing of cpufeatureset.h, this allows removing
> > > the open-coded
> > > feature names, and unifies the feature naming with libxl and the
> > > hypervisor.
> > > 
> > > Introduce a newly auto-generated array that contains the feature
> > > names indexed
> > > at featureset bit position, otherwise using the existing
> > > INIT_FEATURE_NAMES
> > > would require iterating over the array elements until a match
> > > with the expected
> > > bit position is found.
> > > 
> > > Note that leaf names need to be kept, as the current auto-
> > > generated data
> > > doesn't contain the leaf names.
> > > 
> > > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> > 
> > Reviewed-by: Jan Beulich <jbeulich@suse.com>
> 
> Oleksii, now that Jan has provided a Reviewed-by, can you provide a
> release-ack for this to go in?
Based that it is reviewed, I will be happy to have this in 4.19:
 Release-acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>

~ Oleksii
diff mbox series

Patch

diff --git a/tools/include/xen-tools/common-macros.h b/tools/include/xen-tools/common-macros.h
index 07aed92684b5..3e6a66080a4f 100644
--- a/tools/include/xen-tools/common-macros.h
+++ b/tools/include/xen-tools/common-macros.h
@@ -83,6 +83,10 @@ 
 #define __packed __attribute__((__packed__))
 #endif
 
+#ifndef __maybe_unused
+# define __maybe_unused __attribute__((__unused__))
+#endif
+
 #define container_of(ptr, type, member) ({              \
     typeof(((type *)0)->member) *mptr__ = (ptr);        \
     (type *)((char *)mptr__ - offsetof(type, member));  \
diff --git a/tools/misc/xen-cpuid.c b/tools/misc/xen-cpuid.c
index 8893547bebce..2a1ac0ee8326 100644
--- a/tools/misc/xen-cpuid.c
+++ b/tools/misc/xen-cpuid.c
@@ -12,282 +12,33 @@ 
 
 #include <xen-tools/common-macros.h>
 
-static uint32_t nr_features;
-
-static const char *const str_1d[32] =
-{
-    [ 0] = "fpu",  [ 1] = "vme",
-    [ 2] = "de",   [ 3] = "pse",
-    [ 4] = "tsc",  [ 5] = "msr",
-    [ 6] = "pae",  [ 7] = "mce",
-    [ 8] = "cx8",  [ 9] = "apic",
-    /* [10] */     [11] = "sysenter",
-    [12] = "mtrr", [13] = "pge",
-    [14] = "mca",  [15] = "cmov",
-    [16] = "pat",  [17] = "pse36",
-    [18] = "psn",  [19] = "clflush",
-    /* [20] */     [21] = "ds",
-    [22] = "acpi", [23] = "mmx",
-    [24] = "fxsr", [25] = "sse",
-    [26] = "sse2", [27] = "ss",
-    [28] = "htt",  [29] = "tm",
-    [30] = "ia64", [31] = "pbe",
-};
-
-static const char *const str_1c[32] =
-{
-    [ 0] = "sse3",    [ 1] = "pclmulqdq",
-    [ 2] = "dtes64",  [ 3] = "monitor",
-    [ 4] = "ds-cpl",  [ 5] = "vmx",
-    [ 6] = "smx",     [ 7] = "est",
-    [ 8] = "tm2",     [ 9] = "ssse3",
-    [10] = "cntx-id", [11] = "sdgb",
-    [12] = "fma",     [13] = "cx16",
-    [14] = "xtpr",    [15] = "pdcm",
-    /* [16] */        [17] = "pcid",
-    [18] = "dca",     [19] = "sse41",
-    [20] = "sse42",   [21] = "x2apic",
-    [22] = "movebe",  [23] = "popcnt",
-    [24] = "tsc-dl",  [25] = "aesni",
-    [26] = "xsave",   [27] = "osxsave",
-    [28] = "avx",     [29] = "f16c",
-    [30] = "rdrnd",   [31] = "hyper",
-};
-
-static const char *const str_e1d[32] =
-{
-    [ 0] = "fpu",    [ 1] = "vme",
-    [ 2] = "de",     [ 3] = "pse",
-    [ 4] = "tsc",    [ 5] = "msr",
-    [ 6] = "pae",    [ 7] = "mce",
-    [ 8] = "cx8",    [ 9] = "apic",
-    /* [10] */       [11] = "syscall",
-    [12] = "mtrr",   [13] = "pge",
-    [14] = "mca",    [15] = "cmov",
-    [16] = "fcmov",  [17] = "pse36",
-    /* [18] */       [19] = "mp",
-    [20] = "nx",     /* [21] */
-    [22] = "mmx+",   [23] = "mmx",
-    [24] = "fxsr",   [25] = "fxsr+",
-    [26] = "pg1g",   [27] = "rdtscp",
-    /* [28] */       [29] = "lm",
-    [30] = "3dnow+", [31] = "3dnow",
-};
-
-static const char *const str_e1c[32] =
-{
-    [ 0] = "lahf-lm",    [ 1] = "cmp",
-    [ 2] = "svm",        [ 3] = "extapic",
-    [ 4] = "cr8d",       [ 5] = "lzcnt",
-    [ 6] = "sse4a",      [ 7] = "msse",
-    [ 8] = "3dnowpf",    [ 9] = "osvw",
-    [10] = "ibs",        [11] = "xop",
-    [12] = "skinit",     [13] = "wdt",
-    /* [14] */           [15] = "lwp",
-    [16] = "fma4",       [17] = "tce",
-    /* [18] */           [19] = "nodeid",
-    /* [20] */           [21] = "tbm",
-    [22] = "topoext",    [23] = "perfctr-core",
-    [24] = "perfctr-nb", /* [25] */
-    [26] = "dbx",        [27] = "perftsc",
-    [28] = "pcx-l2i",    [29] = "monitorx",
-    [30] = "addr-msk-ext",
-};
-
-static const char *const str_7b0[32] =
-{
-    [ 0] = "fsgsbase", [ 1] = "tsc-adj",
-    [ 2] = "sgx",      [ 3] = "bmi1",
-    [ 4] = "hle",      [ 5] = "avx2",
-    [ 6] = "fdp-exn",  [ 7] = "smep",
-    [ 8] = "bmi2",     [ 9] = "erms",
-    [10] = "invpcid",  [11] = "rtm",
-    [12] = "pqm",      [13] = "depfpp",
-    [14] = "mpx",      [15] = "pqe",
-    [16] = "avx512f",  [17] = "avx512dq",
-    [18] = "rdseed",   [19] = "adx",
-    [20] = "smap",     [21] = "avx512-ifma",
-    [22] = "pcommit",  [23] = "clflushopt",
-    [24] = "clwb",     [25] = "proc-trace",
-    [26] = "avx512pf", [27] = "avx512er",
-    [28] = "avx512cd", [29] = "sha",
-    [30] = "avx512bw", [31] = "avx512vl",
-};
-
-static const char *const str_Da1[32] =
-{
-    [ 0] = "xsaveopt", [ 1] = "xsavec",
-    [ 2] = "xgetbv1",  [ 3] = "xsaves",
-};
-
-static const char *const str_7c0[32] =
-{
-    [ 0] = "prefetchwt1",      [ 1] = "avx512-vbmi",
-    [ 2] = "umip",             [ 3] = "pku",
-    [ 4] = "ospke",            [ 5] = "waitpkg",
-    [ 6] = "avx512-vbmi2",     [ 7] = "cet-ss",
-    [ 8] = "gfni",             [ 9] = "vaes",
-    [10] = "vpclmulqdq",       [11] = "avx512-vnni",
-    [12] = "avx512-bitalg",
-    [14] = "avx512-vpopcntdq",
-
-    [22] = "rdpid",
-    /* 24 */                   [25] = "cldemote",
-    /* 26 */                   [27] = "movdiri",
-    [28] = "movdir64b",        [29] = "enqcmd",
-    [30] = "sgx-lc",           [31] = "pks",
-};
-
-static const char *const str_e7d[32] =
-{
-    /* 6 */                    [ 7] = "hw-pstate",
-    [ 8] = "itsc",             [ 9] = "cpb",
-    [10] = "efro",
-};
-
-static const char *const str_e8b[32] =
-{
-    [ 0] = "clzero",
-    [ 2] = "rstr-fp-err-ptrs",
-
-    /* [ 8] */                 [ 9] = "wbnoinvd",
-
-    [12] = "ibpb",
-    [14] = "ibrs",             [15] = "amd-stibp",
-    [16] = "ibrs-always",      [17] = "stibp-always",
-    [18] = "ibrs-fast",        [19] = "ibrs-same-mode",
-
-    [20] = "no-lmsl",
-    /* [22] */                 [23] = "ppin",
-    [24] = "amd-ssbd",         [25] = "virt-ssbd",
-    [26] = "ssb-no",
-    [28] = "psfd",             [29] = "btc-no",
-    [30] = "ibpb-ret",
-};
-
-static const char *const str_7d0[32] =
-{
-    [ 2] = "avx512-4vnniw", [ 3] = "avx512-4fmaps",
-    [ 4] = "fsrm",
-
-    [ 8] = "avx512-vp2intersect", [ 9] = "srbds-ctrl",
-    [10] = "md-clear",            [11] = "rtm-always-abort",
-    /* 12 */                [13] = "tsx-force-abort",
-    [14] = "serialize",     [15] = "hybrid",
-    [16] = "tsxldtrk",
-    [18] = "pconfig",
-    [20] = "cet-ibt",
-    /* 22 */                [23] = "avx512-fp16",
-
-    [26] = "ibrsb",         [27] = "stibp",
-    [28] = "l1d-flush",     [29] = "arch-caps",
-    [30] = "core-caps",     [31] = "ssbd",
-};
-
-static const char *const str_7a1[32] =
-{
-    [ 0] = "sha512",        [ 1] = "sm3",
-    [ 2] = "sm4",
-    [ 4] = "avx-vnni",      [ 5] = "avx512-bf16",
-
-    [10] = "fzrm",          [11] = "fsrs",
-    [12] = "fsrcs",
-
-    /* 18 */                [19] = "wrmsrns",
+#include <xen/lib/x86/cpu-policy.h>
 
-    /* 22 */                [23] = "avx-ifma",
-};
-
-static const char *const str_e21a[32] =
-{
-    [ 0] = "no-nest-bp",    [ 1] = "fs-gs-ns",
-    [ 2] = "lfence+",
-    [ 6] = "nscb",
-    [ 8] = "auto-ibrs",
-    [10] = "amd-fsrs",      [11] = "amd-fsrc",
-
-    /* 16 */                [17] = "cpuid-user-dis",
-    [18] = "epsf",          [19] = "fsrsc",
-    [20] = "amd-prefetchi",
-
-    /* 26 */                [27] = "sbpb",
-    [28] = "ibpb-brtype",   [29] = "srso-no",
-};
-
-static const char *const str_7b1[32] =
-{
-    [ 0] = "ppin",
-};
-
-static const char *const str_7c1[32] =
-{
-};
-
-static const char *const str_7d1[32] =
-{
-    [ 4] = "avx-vnni-int8",       [ 5] = "avx-ne-convert",
-
-    [10] = "avx-vnni-int16",
-
-    [14] = "prefetchi",
-
-    [18] = "cet-sss",
-};
-
-static const char *const str_7d2[32] =
-{
-    [ 0] = "intel-psfd",    [ 1] = "ipred-ctrl",
-    [ 2] = "rrsba-ctrl",    [ 3] = "ddp-ctrl",
-    [ 4] = "bhi-ctrl",      [ 5] = "mcdt-no",
-};
-
-static const char *const str_m10Al[32] =
-{
-    [ 0] = "rdcl-no",             [ 1] = "eibrs",
-    [ 2] = "rsba",                [ 3] = "skip-l1dfl",
-    [ 4] = "intel-ssb-no",        [ 5] = "mds-no",
-    [ 6] = "if-pschange-mc-no",   [ 7] = "tsx-ctrl",
-    [ 8] = "taa-no",              [ 9] = "mcu-ctrl",
-    [10] = "misc-pkg-ctrl",       [11] = "energy-ctrl",
-    [12] = "doitm",               [13] = "sbdr-ssdp-no",
-    [14] = "fbsdp-no",            [15] = "psdp-no",
-    /* 16 */                      [17] = "fb-clear",
-    [18] = "fb-clear-ctrl",       [19] = "rrsba",
-    [20] = "bhi-no",              [21] = "xapic-status",
-    /* 22 */                      [23] = "ovrclk-status",
-    [24] = "pbrsb-no",            [25] = "gds-ctrl",
-    [26] = "gds-no",              [27] = "rfds-no",
-    [28] = "rfds-clear",
-};
-
-static const char *const str_m10Ah[32] =
-{
-};
+static uint32_t nr_features;
 
 static const struct {
     const char *name;
     const char *abbr;
-    const char *const *strs;
-} decodes[] =
+} leaf_names[] =
 {
-    { "CPUID 0x00000001.edx",        "1d", str_1d },
-    { "CPUID 0x00000001.ecx",        "1c", str_1c },
-    { "CPUID 0x80000001.edx",       "e1d", str_e1d },
-    { "CPUID 0x80000001.ecx",       "e1c", str_e1c },
-    { "CPUID 0x0000000d:1.eax",     "Da1", str_Da1 },
-    { "CPUID 0x00000007:0.ebx",     "7b0", str_7b0 },
-    { "CPUID 0x00000007:0.ecx",     "7c0", str_7c0 },
-    { "CPUID 0x80000007.edx",       "e7d", str_e7d },
-    { "CPUID 0x80000008.ebx",       "e8b", str_e8b },
-    { "CPUID 0x00000007:0.edx",     "7d0", str_7d0 },
-    { "CPUID 0x00000007:1.eax",     "7a1", str_7a1 },
-    { "CPUID 0x80000021.eax",      "e21a", str_e21a },
-    { "CPUID 0x00000007:1.ebx",     "7b1", str_7b1 },
-    { "CPUID 0x00000007:2.edx",     "7d2", str_7d2 },
-    { "CPUID 0x00000007:1.ecx",     "7c1", str_7c1 },
-    { "CPUID 0x00000007:1.edx",     "7d1", str_7d1 },
-    { "MSR_ARCH_CAPS.lo",         "m10Al", str_m10Al },
-    { "MSR_ARCH_CAPS.hi",         "m10Ah", str_m10Ah },
+    { "CPUID 0x00000001.edx",        "1d" },
+    { "CPUID 0x00000001.ecx",        "1c" },
+    { "CPUID 0x80000001.edx",       "e1d" },
+    { "CPUID 0x80000001.ecx",       "e1c" },
+    { "CPUID 0x0000000d:1.eax",     "Da1" },
+    { "CPUID 0x00000007:0.ebx",     "7b0" },
+    { "CPUID 0x00000007:0.ecx",     "7c0" },
+    { "CPUID 0x80000007.edx",       "e7d" },
+    { "CPUID 0x80000008.ebx",       "e8b" },
+    { "CPUID 0x00000007:0.edx",     "7d0" },
+    { "CPUID 0x00000007:1.eax",     "7a1" },
+    { "CPUID 0x80000021.eax",      "e21a" },
+    { "CPUID 0x00000007:1.ebx",     "7b1" },
+    { "CPUID 0x00000007:2.edx",     "7d2" },
+    { "CPUID 0x00000007:1.ecx",     "7c1" },
+    { "CPUID 0x00000007:1.edx",     "7d1" },
+    { "MSR_ARCH_CAPS.lo",         "m10Al" },
+    { "MSR_ARCH_CAPS.hi",         "m10Ah" },
 };
 
 #define COL_ALIGN "24"
@@ -305,12 +56,6 @@  static void dump_leaf(uint32_t leaf, const char *const *strs)
 {
     unsigned i;
 
-    if ( !strs )
-    {
-        printf(" ???");
-        return;
-    }
-
     for ( i = 0; i < 32; ++i )
         if ( leaf & (1u << i) )
         {
@@ -326,6 +71,7 @@  static void decode_featureset(const uint32_t *features,
                               const char *name,
                               bool detail)
 {
+    static const uint32_t __maybe_unused known_features[] = INIT_KNOWN_FEATURES;
     unsigned int i;
 
     printf("%-"COL_ALIGN"s        ", name);
@@ -336,11 +82,21 @@  static void decode_featureset(const uint32_t *features,
     if ( !detail )
         return;
 
-    for ( i = 0; i < length && i < ARRAY_SIZE(decodes); ++i )
+    /* Ensure leaf names stay in sync with the policy leaf count. */
+    BUILD_BUG_ON(ARRAY_SIZE(known_features) != ARRAY_SIZE(leaf_names));
+
+    for ( i = 0; i < length && i < ARRAY_SIZE(leaf_names); ++i )
     {
-        printf("  [%02u] %-"COL_ALIGN"s", i, decodes[i].name ?: "<UNKNOWN>");
-        if ( decodes[i].name )
-            dump_leaf(features[i], decodes[i].strs);
+        static const char *const feature_names[] = INIT_FEATURE_NAME_ARRAY;
+
+        /* Ensure feature names stays in sync with number of feature words. */
+        BUILD_BUG_ON(ARRAY_SIZE(feature_names) !=
+                     ARRAY_SIZE(leaf_names) * sizeof(*features) * 8);
+
+        printf("  [%02u] %-"COL_ALIGN"s", i, leaf_names[i].name ?: "<UNKNOWN>");
+
+        /* Attempt to print features anyway even if the leaf name is unknown. */
+        dump_leaf(features[i], &feature_names[i * 32]);
         printf("\n");
     }
 }
@@ -355,8 +111,8 @@  static void dump_info(xc_interface *xch, bool detail)
     if ( !detail )
     {
         printf("       %"COL_ALIGN"s ", "KEY");
-        for ( i = 0; i < ARRAY_SIZE(decodes); ++i )
-            printf("%-8s ", decodes[i].abbr ?: "???");
+        for ( i = 0; i < ARRAY_SIZE(leaf_names); ++i )
+            printf("%-8s ", leaf_names[i].abbr ?: "???");
         printf("\n");
     }
 
diff --git a/xen/tools/gen-cpuid.py b/xen/tools/gen-cpuid.py
index 380b9d973a67..c0caa3bdebef 100755
--- a/xen/tools/gen-cpuid.py
+++ b/xen/tools/gen-cpuid.py
@@ -475,6 +475,32 @@  def write_results(state):
     state.output.write(
 """}
 
+""")
+
+    state.output.write(
+"""
+#define INIT_FEATURE_NAME_ARRAY { \\
+""")
+
+    try:
+        _tmp = state.names.iteritems()
+    except AttributeError:
+        _tmp = state.names.items()
+
+    for bit, name in sorted(_tmp):
+        state.output.write(
+            '    [%s] = "%s",\\\n' % (bit, name.lower().replace("_", "-"))
+            )
+
+    # Ensure array size matches featureset size.
+    if not state.names.get(state.nr_entries * 32 - 1, ""):
+        state.output.write(
+            '    [%s] = NULL,\\\n' % (state.nr_entries * 32 - 1)
+            )
+
+    state.output.write(
+"""}
+
 """)
 
     for idx, text in enumerate(state.bitfields):