# Commit fae0372140befb88d890a30704a8ec058c902af8
# Date 2013-03-25 14:28:31 +0100
# Author Jan Beulich <jbeulich@suse.com>
# Committer Jan Beulich <jbeulich@suse.com>
IOMMU: properly check whether interrupt remapping is enabled

... rather than the IOMMU as a whole.

That in turn required to make sure iommu_intremap gets properly
cleared when the respective initialization fails (or isn't being
done at all).

Along with making sure interrupt remapping doesn't get inconsistently
enabled on some IOMMUs and not on others in the VT-d code, this in turn
allowed quite a bit of cleanup on the VT-d side (removed from the
backport).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: "Zhang, Xiantao" <xiantao.zhang@intel.com>

--- a/xen/arch/x86/msi.c
+++ b/xen/arch/x86/msi.c
@@ -204,7 +204,7 @@ static void read_msi_msg(struct msi_desc
         BUG();
     }
 
-    if ( iommu_enabled )
+    if ( iommu_intremap )
         iommu_read_msi_from_ire(entry, msg);
 }
 
@@ -212,7 +212,7 @@ static void write_msi_msg(struct msi_des
 {
     entry->msg = *msg;
 
-    if ( iommu_enabled )
+    if ( iommu_intremap )
     {
         ASSERT(msg != &entry->msg);
         iommu_update_ire_from_msi(entry, msg);
@@ -482,7 +482,7 @@ int msi_free_irq(struct msi_desc *entry)
     }
 
     /* Free the unused IRTE if intr remap enabled */
-    if ( iommu_enabled )
+    if ( iommu_intremap )
         iommu_update_ire_from_msi(entry, NULL);
 
     list_del(&entry->list);
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -469,6 +469,8 @@ int __init iommu_setup(void)
         rc = iommu_hardware_setup();
         iommu_enabled = (rc == 0);
     }
+    if ( !iommu_enabled )
+        iommu_intremap = 0;
 
     if ( (force_iommu && !iommu_enabled) ||
          (force_intremap && !iommu_intremap) )
@@ -485,9 +487,12 @@ int __init iommu_setup(void)
     }
     printk("I/O virtualisation %sabled\n", iommu_enabled ? "en" : "dis");
     if ( iommu_enabled )
+    {
         printk(" - Dom0 mode: %s\n",
                iommu_passthrough ? "Passthrough" :
                iommu_dom0_strict ? "Strict" : "Relaxed");
+        printk("Interrupt remapping %sabled\n", iommu_intremap ? "en" : "dis");
+    }
 
     return rc;
 }
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -2072,6 +2072,9 @@ static int init_vtd_hw(void)
                 break;
             }
         }
+        if ( !iommu_intremap )
+            for_each_drhd_unit ( drhd )
+                disable_intremap(drhd->iommu);
     }
 
     /*
--- a/xen/include/asm-x86/io_apic.h
+++ b/xen/include/asm-x86/io_apic.h
@@ -129,7 +129,7 @@ struct IO_APIC_route_entry {
 extern struct mpc_config_ioapic mp_ioapics[MAX_IO_APICS];
 
 /* Only need to remap ioapic RTE (reg: 10~3Fh) */
-#define ioapic_reg_remapped(reg) (iommu_enabled && ((reg) >= 0x10))
+#define ioapic_reg_remapped(reg) (iommu_intremap && ((reg) >= 0x10))
 
 static inline unsigned int __io_apic_read(unsigned int apic, unsigned int reg)
 {