[PATCH v3.5 3/4] tools/xen-cpuid: Use automatically generated feature names

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

From: Roger Pau Monné <roger.pau@xxxxxxxxxx>

Have gen-cpuid.py write out INIT_FEATURE_VAL_TO_NAME, derived from the same
data source as INIT_FEATURE_NAME_TO_VAL, although both aliases of common_1d
are needed.

In xen-cpuid.c, sanity check at build time that leaf_info[] and
feature_names[] are of sensible length.

As dump_leaf() rendered missing names as numbers, always dump leaves even if
we don't have the leaf name.  This conversion was argumably missed in commit
59afdb8a81d6 ("tools/misc: Tweak reserved bit handling for xen-cpuid").

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>

Differences in names are:

 sysenter    -> sep
 tm          -> tm1
 ds-cpl      -> dscpl
 est         -> eist
 sse41       -> sse4-1
 sse42       -> sse4-2
 movebe      -> movbe
 tsc-dl      -> tsc-deadline
 rdrnd       -> rdrand
 hyper       -> hypervisor
 mmx+        -> mmext
 fxsr+       -> ffxsr
 pg1g        -> page1gb
 3dnow+      -> 3dnowext
 cmp         -> cmp-legacy
 cr8d        -> cr8-legacy
 lzcnt       -> abm
 msse        -> misalignsse
 3dnowpf     -> 3dnowprefetch
 nodeid      -> nodeid-msr
 dbx         -> dbext
 tsc-adj     -> tsc-adjust
 fdp-exn     -> fdp-excp-only
 deffp       -> no-fpu-sel
 <24>        -> bld
 ppin        -> amd-ppin
 lfence+     -> lfence-dispatch
 ppin        -> intel-ppin
 energy-ctrl -> energy-filtering

Apparently BLD missed the update to xen-cpuid.c.  It appears to be the only
one.  Several of the + names would be nice to keep as were, but doing so isn't
nice in gen-cpuid.  Any changes would alter the {dom0-}cpuid= cmdline options,
but we intentionally don't list them, so I'm not worried.

Thoughts?

v3:
 * Rework somewhat.
 * Insert aliases of common_1d.

v4:
 * Pad at the gen stage.  I don't like this, but I'm clearly outvoted on the 
matter.
---
 tools/misc/xen-cpuid.c | 16 ++++++++--------
 xen/tools/gen-cpuid.py | 29 +++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/tools/misc/xen-cpuid.c b/tools/misc/xen-cpuid.c
index 6ee835b22949..51009683da1b 100644
--- a/tools/misc/xen-cpuid.c
+++ b/tools/misc/xen-cpuid.c
@@ -11,6 +11,7 @@
 #include <xenguest.h>
 
 #include <xen-tools/common-macros.h>
+#include <xen/lib/x86/cpuid-autogen.h>
 
 static uint32_t nr_features;
 
@@ -291,6 +292,8 @@ static const struct {
 
 #define COL_ALIGN "24"
 
+static const char *const feature_names[] = INIT_FEATURE_VAL_TO_NAME;
+
 static const char *const fs_names[] = {
     [XEN_SYSCTL_cpu_featureset_raw]     = "Raw",
     [XEN_SYSCTL_cpu_featureset_host]    = "Host",
@@ -304,12 +307,6 @@ 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) )
         {
@@ -327,6 +324,10 @@ static void decode_featureset(const uint32_t *features,
 {
     unsigned int i;
 
+    /* If this trips, you probably need to extend leaf_info[] above. */
+    BUILD_BUG_ON(ARRAY_SIZE(leaf_info) != FEATURESET_NR_ENTRIES);
+    BUILD_BUG_ON(ARRAY_SIZE(feature_names) != FEATURESET_NR_ENTRIES * 32);
+
     printf("%-"COL_ALIGN"s        ", name);
     for ( i = 0; i < length; ++i )
         printf("%08x%c", features[i],
@@ -338,8 +339,7 @@ static void decode_featureset(const uint32_t *features,
     for ( i = 0; i < length && i < ARRAY_SIZE(leaf_info); ++i )
     {
         printf("  [%02u] %-"COL_ALIGN"s", i, leaf_info[i].name ?: "<UNKNOWN>");
-        if ( leaf_info[i].name )
-            dump_leaf(features[i], leaf_info[i].strs);
+        dump_leaf(features[i], &feature_names[i * 32]);
         printf("\n");
     }
 }
diff --git a/xen/tools/gen-cpuid.py b/xen/tools/gen-cpuid.py
index 79d7f5c8e1c9..601eec608983 100755
--- a/xen/tools/gen-cpuid.py
+++ b/xen/tools/gen-cpuid.py
@@ -470,6 +470,35 @@ def write_results(state):
     state.output.write(
 """}
 
+""")
+
+    state.output.write(
+"""
+#define INIT_FEATURE_VAL_TO_NAME { \\
+""")
+
+    for name, bit in sorted(state.values.items()):
+        state.output.write(
+            '    [%s] = "%s",\\\n' % (bit, name)
+            )
+
+        # Add the other alias for 1d/e1d common bits.  64 is the difference
+        # between 1d and e1d.
+        if bit in state.common_1d:
+            state.output.write(
+                '    [%s] = "%s",\\\n' % (64 + bit, name)
+            )
+
+    # Pad to an exact multiple of FEATURESET_SIZE if necessary
+    pad_feat = state.nr_entries * 32 - 1
+    if not state.names.get(pad_feat):
+        state.output.write(
+            '    [%s] = NULL,\\\n' % (pad_feat, )
+        )
+
+    state.output.write(
+"""}
+
 """)
 
     for idx, text in enumerate(state.bitfields):
-- 
2.30.2