[xen master] x86: Rearrange struct cpuinfo_x86 to introduce a vfm field

[patchbot@xxxxxxx]

commit 673c56347713c1f87a1c88613d03de768f690de6
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Tue Jul 15 20:15:18 2025 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Thu Jul 17 18:54:49 2025 +0100

    x86: Rearrange struct cpuinfo_x86 to introduce a vfm field
    
    Intel have run out of model space in Family 6 and will start using Family 19
    starting with Diamond Rapids.  Xen, like Linux, has model checking logic 
which
    will malfunction owing to bad assumptions about the family field.
    
    Reorder the family, vendor and model fields so they can be accessed together
    as a single vfm field.
    
    As we're cleaning up the logic, take the opportunity to introduce better
    names, dropping the x86 prefix.
    
    No functional change.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/include/asm/cpufeature.h | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/include/asm/cpufeature.h 
b/xen/arch/x86/include/asm/cpufeature.h
index 56d6ed1a87..4d45f14da4 100644
--- a/xen/arch/x86/include/asm/cpufeature.h
+++ b/xen/arch/x86/include/asm/cpufeature.h
@@ -20,10 +20,30 @@
 #ifndef __ASSEMBLY__
 
 struct cpuinfo_x86 {
-    unsigned char x86;                 /* CPU family */
-    unsigned char x86_vendor;          /* CPU vendor */
-    unsigned char x86_model;
-    unsigned char x86_mask;
+    /* TODO: Phase out the x86 prefixed names. */
+    union {
+        struct {
+            union {
+                uint8_t x86_model;
+                uint8_t model;
+            };
+            union {
+                uint8_t x86;
+                uint8_t family;
+            };
+            union {
+                uint8_t x86_vendor;
+                uint8_t vendor;
+            };
+            uint8_t _rsvd;
+        };
+        uint32_t vfm;                  /* Vendor Family Model */
+    };
+    union {
+        uint8_t x86_mask;
+        uint8_t stepping;
+    };
+
     unsigned int cpuid_level;          /* Maximum supported CPUID level */
     unsigned int extended_cpuid_level; /* Maximum supported CPUID extended 
level */
     unsigned int x86_capability[NCAPINTS];
--
generated by git-patchbot for /home/xen/git/xen.git#master