i386: host_vendor_fms() helper function

Helper function for code that needs to check the host CPU
vendor/family/model/stepping values.
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Message-Id: <20170309181212.18864-2-ehabkost@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>

target/i386/cpu.c

@@ -688,6 +688,25 @@ void host_cpuid(uint32_t function, uint32_t count,
         *edx = vec[3];
 }
 
+void host_vendor_fms(char *vendor, int *family, int *model, int *stepping)
+{
+    uint32_t eax, ebx, ecx, edx;
+
+    host_cpuid(0x0, 0, &eax, &ebx, &ecx, &edx);
+    x86_cpu_vendor_words2str(vendor, ebx, edx, ecx);
+
+    host_cpuid(0x1, 0, &eax, &ebx, &ecx, &edx);
+    if (family) {
+        *family = ((eax >> 8) & 0x0F) + ((eax >> 20) & 0xFF);
+    }
+    if (model) {
+        *model = ((eax >> 4) & 0x0F) | ((eax & 0xF0000) >> 12);
+    }
+    if (stepping) {
+        *stepping = eax & 0x0F;
+    }
+}
+
 /* CPU class name definitions: */
 
 #define X86_CPU_TYPE_SUFFIX "-" TYPE_X86_CPU

target/i386/cpu.h

@@ -1436,6 +1436,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
 void cpu_clear_apic_feature(CPUX86State *env);
 void host_cpuid(uint32_t function, uint32_t count,
                 uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx);
+void host_vendor_fms(char *vendor, int *family, int *model, int *stepping);
 
 /* helper.c */
 int x86_cpu_handle_mmu_fault(CPUState *cpu, vaddr addr,