Re: [Xen-ia64-devel] [PATCH] Fix SMP-unsafe with XENMEM_add_to_physmap on HVM

[Kouya Shimura <kouya@xxxxxxxxxxxxxx>]

Isaku Yamahata writes:
> Doesn't flush_tlb_for_log_dirty() have same issue?

It's OK since flush_tlb_for_log_dirty() is called only while a domain
is paused.

> As a minor code nit.
> Could it be moved the new code fragment under the directory,
> arch/ia64/vmx?

Sure, new one attached.

Thanks,
Kouya

Signed-off-by: Kouya Shimura <kouya@xxxxxxxxxxxxxx>

diff -r 08f77df14cba xen/arch/ia64/vmx/vtlb.c
--- a/xen/arch/ia64/vmx/vtlb.c  Wed Jul 02 11:30:37 2008 +0900
+++ b/xen/arch/ia64/vmx/vtlb.c  Mon Jul 07 12:42:03 2008 +0900
@@ -623,6 +623,30 @@
     local_flush_tlb_all();
 }
 
+static void __thash_purge_all(void *arg)
+{
+    struct vcpu *v = arg;
+
+    BUG_ON(vcpu_runnable(v) || v->is_running);
+    thash_purge_all(v);
+}
+
+void vmx_vcpu_flush_vtlb_all(VCPU *v)
+{
+    if (v == current) {
+        thash_purge_all(v);
+        return;
+    }
+
+    /* SMP safe */
+    vcpu_pause(v);
+    if (v->processor == smp_processor_id())
+        __thash_purge_all(v);
+    else
+        smp_call_function_single(v->processor, __thash_purge_all, v, 1, 1);
+    vcpu_unpause(v);
+}
+
 
 /*
  * Lookup the hash table and its collision chain to find an entry
diff -r 08f77df14cba xen/arch/ia64/xen/vhpt.c
--- a/xen/arch/ia64/xen/vhpt.c  Wed Jul 02 11:30:37 2008 +0900
+++ b/xen/arch/ia64/xen/vhpt.c  Mon Jul 07 12:42:03 2008 +0900
@@ -249,31 +249,20 @@
 // (e.g. vcpu == current), smp_mb() is unnecessary.
 void vcpu_flush_vtlb_all(struct vcpu *v)
 {
-       if (VMX_DOMAIN(v)) {
-               /* This code may be call for remapping shared_info and
-                  grant_table share page from guest_physmap_remove_page()
-                  in arch_memory_op() XENMEM_add_to_physmap to realize
-                  PV-on-HVM feature. */
-               /* FIXME: This is not SMP-safe yet about p2m table */
-               /* Purge vTLB for VT-i domain */
-               thash_purge_all(v);
-       }
-       else {
-               /* First VCPU tlb.  */
-               vcpu_purge_tr_entry(&PSCBX(v,dtlb));
-               vcpu_purge_tr_entry(&PSCBX(v,itlb));
-               smp_mb();
+       /* First VCPU tlb.  */
+       vcpu_purge_tr_entry(&PSCBX(v,dtlb));
+       vcpu_purge_tr_entry(&PSCBX(v,itlb));
+       smp_mb();
 
-               /* Then VHPT.  */
-               if (HAS_PERVCPU_VHPT(v->domain))
-                       vcpu_vhpt_flush(v);
-               else
-                       local_vhpt_flush();
-               smp_mb();
+       /* Then VHPT.  */
+       if (HAS_PERVCPU_VHPT(v->domain))
+               vcpu_vhpt_flush(v);
+       else
+               local_vhpt_flush();
+       smp_mb();
 
-               /* Then mTLB.  */
-               local_flush_tlb_all();
-       }
+       /* Then mTLB.  */
+       local_flush_tlb_all();
 
        /* We could clear bit in d->domain_dirty_cpumask only if domain d in
           not running on this processor.  There is currently no easy way to
@@ -296,6 +285,15 @@
        for_each_vcpu(d, v) {
                if (!v->is_initialised)
                        continue;
+
+               if (VMX_DOMAIN(v)) {
+                       // This code may be called for remapping shared_info
+                       // and grant_table from guest_physmap_remove_page()
+                       // in arch_memory_op() XENMEM_add_to_physmap to realize
+                       // PV-on-HVM feature.
+                       vmx_vcpu_flush_vtlb_all(v);
+                       continue;
+               }
 
                if (v->processor == cpu)
                        vcpu_flush_vtlb_all(v);
diff -r 08f77df14cba xen/include/asm-ia64/vmmu.h
--- a/xen/include/asm-ia64/vmmu.h       Wed Jul 02 11:30:37 2008 +0900
+++ b/xen/include/asm-ia64/vmmu.h       Mon Jul 07 12:42:03 2008 +0900
@@ -175,6 +175,7 @@
  *
  */
 extern void thash_purge_all(struct vcpu *v);
+extern void vmx_vcpu_flush_vtlb_all(struct vcpu *v);
 
 /*
  * Lookup the hash table and its collision chain to find an entry

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