x86/cpuid: Drop a guests cached x86 family and model information

The model information isn't used at all, and the family information is only
used once.

Make get_cpu_family() a static inline (as it is just basic calculation, and
the function call is probably more expensive than the function itself) and
rearange the logic to avoid calculating model entirely if the caller doesn't
want it.

Calculate a guests family only when necessary in hvm_select_ioreq_server().

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

xen/arch/x86/cpu/common.c

@@ -186,25 +186,6 @@ int get_cpu_vendor(uint32_t b, uint32_t c, uint32_t d, enum get_cpu_vendor mode)
 	return X86_VENDOR_UNKNOWN;
 }
 
-uint8_t get_cpu_family(uint32_t raw, uint8_t *model, uint8_t *stepping)
-{
-	uint8_t fam, mod;
-
-	fam = (raw >> 8) & 0xf;
-	if (fam == 0xf)
-		fam += (raw >> 20) & 0xff;
-
-	mod = (raw >> 4) & 0xf;
-	if (fam >= 0x6)
-		mod |= (raw >> 12) & 0xf0;
-
-	if (model)
-		*model = mod;
-	if (stepping)
-		*stepping = raw & 0xf;
-	return fam;
-}
-
 static inline u32 _phys_pkg_id(u32 cpuid_apic, int index_msb)
 {
 	return cpuid_apic >> index_msb;

xen/arch/x86/domain.c

@@ -609,8 +609,6 @@ int arch_domain_create(struct domain *d, unsigned int domcr_flags,
             goto fail;
 
         d->arch.x86_vendor = boot_cpu_data.x86_vendor;
-        d->arch.x86        = boot_cpu_data.x86;
-        d->arch.x86_model  = boot_cpu_data.x86_model;
 
         d->arch.ioport_caps = 
             rangeset_new(d, "I/O Ports", RANGESETF_prettyprint_hex);

xen/arch/x86/domctl.c

@@ -171,8 +171,6 @@ static int update_domain_cpuid_info(struct domain *d,
     }
 
     case 1:
-        d->arch.x86 = get_cpu_family(ctl->eax, &d->arch.x86_model, NULL);
-
         if ( is_pv_domain(d) && ((levelling_caps & LCAP_1cd) == LCAP_1cd) )
         {
             uint64_t mask = cpuidmask_defaults._1cd;

xen/arch/x86/hvm/ioreq.c

@@ -1125,7 +1125,7 @@ struct hvm_ioreq_server *hvm_select_ioreq_server(struct domain *d,
          (p->addr & ~3) == 0xcfc &&
          CF8_ENABLED(cf8) )
     {
-        uint32_t sbdf;
+        uint32_t sbdf, x86_fam;
 
         /* PCI config data cycle */
 
@@ -1141,7 +1141,9 @@ struct hvm_ioreq_server *hvm_select_ioreq_server(struct domain *d,
         /* AMD extended configuration space access? */
         if ( CF8_ADDR_HI(cf8) &&
              d->arch.x86_vendor == X86_VENDOR_AMD &&
-             d->arch.x86 >= 0x10 && d->arch.x86 <= 0x17 )
+             (x86_fam = get_cpu_family(
+                 d->arch.cpuid->basic.raw_fms, NULL, NULL)) > 0x10 &&
+             x86_fam <= 0x17 )
         {
             uint64_t msr_val;
 

xen/include/asm-x86/cpuid.h

@@ -107,7 +107,7 @@ struct cpuid_policy
             uint32_t max_leaf, /* b */:32, /* c */:32, /* d */:32;
 
             /* Leaf 0x1 - Family/model/stepping and features. */
-            uint32_t /* a */:32, /* b */:32;
+            uint32_t raw_fms, /* b */:32;
             union {
                 uint32_t _1c;
                 struct { DECL_BITFIELD(1c); };

xen/include/asm-x86/domain.h

@@ -338,9 +338,7 @@ struct arch_domain
     bool_t auto_unmask;
 
     /* Values snooped from updates to cpuids[] (below). */
-    u8 x86;                  /* CPU family */
     u8 x86_vendor;           /* CPU vendor */
-    u8 x86_model;            /* CPU model */
 
     /*
      * The width of the FIP/FDP register in the FPU that needs to be

xen/include/asm-x86/processor.h

@@ -625,7 +625,28 @@ enum get_cpu_vendor {
 };
 
 int get_cpu_vendor(uint32_t b, uint32_t c, uint32_t d, enum get_cpu_vendor mode);
-uint8_t get_cpu_family(uint32_t raw, uint8_t *model, uint8_t *stepping);
+
+static inline uint8_t get_cpu_family(uint32_t raw, uint8_t *model,
+                                     uint8_t *stepping)
+{
+    uint8_t fam = (raw >> 8) & 0xf;
+
+    if ( fam == 0xf )
+        fam += (raw >> 20) & 0xff;
+
+    if ( model )
+    {
+        uint8_t mod = (raw >> 4) & 0xf;
+
+        if ( fam >= 0x6 )
+            mod |= (raw >> 12) & 0xf0;
+
+        *model = mod;
+    }
+    if ( stepping )
+        *stepping = raw & 0xf;
+    return fam;
+}
 
 #endif /* !__ASSEMBLY__ */