[Xen-devel] [PATCH 4/8] x86/AMD: distinguish compute units from hyper-threads

["Jan Beulich" <JBeulich@xxxxxxxx>]

Fam17 replaces CUs by HTs, which we should reflect accordingly, even if
the difference is not very big. The most relevant change (requiring some
code restructuring) is that the topoext feature no longer means there is
a valid CU ID.

Take the opportunity and convert wrongly plain int variables in
set_cpu_sibling_map() to unsigned int.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/cpu/amd.c
+++ b/xen/arch/x86/cpu/amd.c
@@ -504,17 +504,23 @@ static void amd_get_topology(struct cpui
                 u32 eax, ebx, ecx, edx;
 
                 cpuid(0x8000001e, &eax, &ebx, &ecx, &edx);
-                c->compute_unit_id = ebx & 0xFF;
                 c->x86_num_siblings = ((ebx >> 8) & 0x3) + 1;
+
+               if (c->x86 < 0x17)
+                       c->compute_unit_id = ebx & 0xFF;
+               else {
+                       c->cpu_core_id = ebx & 0xFF;
+                       c->x86_max_cores /= c->x86_num_siblings;
+               }
         }
         
         if (opt_cpu_info)
                 printk("CPU %d(%d) -> Processor %d, %s %d\n",
                        cpu, c->x86_max_cores, c->phys_proc_id,
-                       cpu_has(c, X86_FEATURE_TOPOEXT) ? "Compute Unit" : 
-                                                         "Core",
-                       cpu_has(c, X86_FEATURE_TOPOEXT) ? c->compute_unit_id :
-                                                         c->cpu_core_id);
+                       c->compute_unit_id != INVALID_CUID ? "Compute Unit"
+                                                          : "Core",
+                       c->compute_unit_id != INVALID_CUID ? c->compute_unit_id
+                                                          : c->cpu_core_id);
 }
 
 static void early_init_amd(struct cpuinfo_x86 *c)
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -236,33 +236,41 @@ static void link_thread_siblings(int cpu
     cpumask_set_cpu(cpu2, per_cpu(cpu_core_mask, cpu1));
 }
 
-static void set_cpu_sibling_map(int cpu)
+static void set_cpu_sibling_map(unsigned int cpu)
 {
-    int i;
+    unsigned int i;
     struct cpuinfo_x86 *c = cpu_data;
 
     cpumask_set_cpu(cpu, &cpu_sibling_setup_map);
 
     cpumask_set_cpu(cpu, socket_cpumask[cpu_to_socket(cpu)]);
+    cpumask_set_cpu(cpu, per_cpu(cpu_core_mask, cpu));
+    cpumask_set_cpu(cpu, per_cpu(cpu_sibling_mask, cpu));
 
     if ( c[cpu].x86_num_siblings > 1 )
     {
         for_each_cpu ( i, &cpu_sibling_setup_map )
         {
-            if ( cpu_has(c, X86_FEATURE_TOPOEXT) ) {
-                if ( (c[cpu].phys_proc_id == c[i].phys_proc_id) &&
-                     (c[cpu].compute_unit_id == c[i].compute_unit_id) )
+            if ( cpu == i || c[cpu].phys_proc_id != c[i].phys_proc_id )
+                continue;
+            if ( c[cpu].compute_unit_id != INVALID_CUID &&
+                 c[i].compute_unit_id != INVALID_CUID )
+            {
+                if ( c[cpu].compute_unit_id == c[i].compute_unit_id )
                     link_thread_siblings(cpu, i);
-            } else if ( (c[cpu].phys_proc_id == c[i].phys_proc_id) &&
-                        (c[cpu].cpu_core_id == c[i].cpu_core_id) ) {
-                link_thread_siblings(cpu, i);
             }
+            else if ( c[cpu].cpu_core_id != XEN_INVALID_CORE_ID &&
+                      c[i].cpu_core_id != XEN_INVALID_CORE_ID )
+            {
+                if ( c[cpu].cpu_core_id == c[i].cpu_core_id )
+                    link_thread_siblings(cpu, i);
+            }
+            else
+                printk(XENLOG_WARNING
+                       "CPU%u: unclear relationship with CPU%u\n",
+                       cpu, i);
         }
     }
-    else
-    {
-        cpumask_set_cpu(cpu, per_cpu(cpu_sibling_mask, cpu));
-    }
 
     if ( c[cpu].x86_max_cores == 1 )
     {





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