[Xen-devel] [PATCH v2 3/9] x86/mm: honor opt_pcid also for 32-bit PV domains

[Jan Beulich <jbeulich@xxxxxxxx>]

I can't see any technical or performance reason why we should treat
32-bit PV different from 64-bit PV in this regard.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

--- a/xen/arch/x86/pv/domain.c
+++ b/xen/arch/x86/pv/domain.c
@@ -180,7 +180,24 @@ int switch_compat(struct domain *d)
     d->arch.x87_fip_width = 4;
 
     d->arch.pv.xpti = false;
-    d->arch.pv.pcid = false;
+
+    if ( use_invpcid && cpu_has_pcid )
+        switch ( ACCESS_ONCE(opt_pcid) )
+        {
+        case PCID_OFF:
+        case PCID_XPTI:
+            d->arch.pv.pcid = false;
+            break;
+
+        case PCID_ALL:
+        case PCID_NOXPTI:
+            d->arch.pv.pcid = true;
+            break;
+
+        default:
+            ASSERT_UNREACHABLE();
+            break;
+        }
 
     return 0;
 
@@ -312,7 +329,7 @@ int pv_domain_initialise(struct domain *
 
     d->arch.pv.xpti = is_hardware_domain(d) ? opt_xpti_hwdom : opt_xpti_domu;
 
-    if ( !is_pv_32bit_domain(d) && use_invpcid && cpu_has_pcid )
+    if ( use_invpcid && cpu_has_pcid )
         switch ( ACCESS_ONCE(opt_pcid) )
         {
         case PCID_OFF:


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