x86_32: [un]map_domain_page() is now IRQ safe.

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

xen/arch/x86/x86_32/domain_page.c

@@ -43,15 +43,13 @@ static inline struct vcpu *mapcache_current_vcpu(void)
 
 void *map_domain_page(unsigned long mfn)
 {
-    unsigned long va;
-    unsigned int idx, i, flags;
+    unsigned long va, flags;
+    unsigned int idx, i;
     struct vcpu *v;
     struct mapcache_domain *dcache;
     struct mapcache_vcpu *vcache;
     struct vcpu_maphash_entry *hashent;
 
-    ASSERT(!in_irq());
-
     perfc_incr(map_domain_page_count);
 
     v = mapcache_current_vcpu();
@@ -59,6 +57,8 @@ void *map_domain_page(unsigned long mfn)
     dcache = &v->domain->arch.mapcache;
     vcache = &v->arch.mapcache;
 
+    local_irq_save(flags);
+
     hashent = &vcache->hash[MAPHASH_HASHFN(mfn)];
     if ( hashent->mfn == mfn )
     {
@@ -70,7 +70,7 @@ void *map_domain_page(unsigned long mfn)
         goto out;
     }
 
-    spin_lock_irqsave(&dcache->lock, flags);
+    spin_lock(&dcache->lock);
 
     /* Has some other CPU caused a wrap? We must flush if so. */
     if ( unlikely(dcache->epoch != vcache->shadow_epoch) )
@@ -106,11 +106,12 @@ void *map_domain_page(unsigned long mfn)
     set_bit(idx, dcache->inuse);
     dcache->cursor = idx + 1;
 
-    spin_unlock_irqrestore(&dcache->lock, flags);
+    spin_unlock(&dcache->lock);
 
     l1e_write(&dcache->l1tab[idx], l1e_from_pfn(mfn, __PAGE_HYPERVISOR));
 
  out:
+    local_irq_restore(flags);
     va = MAPCACHE_VIRT_START + (idx << PAGE_SHIFT);
     return (void *)va;
 }
@@ -120,11 +121,9 @@ void unmap_domain_page(const void *va)
     unsigned int idx;
     struct vcpu *v;
     struct mapcache_domain *dcache;
-    unsigned long mfn;
+    unsigned long mfn, flags;
     struct vcpu_maphash_entry *hashent;
 
-    ASSERT(!in_irq());
-
     ASSERT((void *)MAPCACHE_VIRT_START <= va);
     ASSERT(va < (void *)MAPCACHE_VIRT_END);
 
@@ -136,6 +135,8 @@ void unmap_domain_page(const void *va)
     mfn = l1e_get_pfn(dcache->l1tab[idx]);
     hashent = &v->arch.mapcache.hash[MAPHASH_HASHFN(mfn)];
 
+    local_irq_save(flags);
+
     if ( hashent->idx == idx )
     {
         ASSERT(hashent->mfn == mfn);
@@ -164,6 +165,8 @@ void unmap_domain_page(const void *va)
         /* /Second/, mark as garbage. */
         set_bit(idx, dcache->garbage);
     }
+
+    local_irq_restore(flags);
 }
 
 void mapcache_domain_init(struct domain *d)