1 files changed, 45 insertions, 7 deletions

diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
index 967633ad98c4..969570491c39 100644
--- a/arch/x86/xen/pci-swiotlb-xen.c
+++ b/arch/x86/xen/pci-swiotlb-xen.c
@@ -8,6 +8,14 @@
 #include <xen/xen.h>
 #include <asm/iommu_table.h>
 
+
+#include <asm/xen/swiotlb-xen.h>
+#ifdef CONFIG_X86_64
+#include <asm/iommu.h>
+#include <asm/dma.h>
+#endif
+#include <linux/export.h>
+
 int xen_swiotlb __read_mostly;
 
 static struct dma_map_ops xen_swiotlb_dma_ops = {
@@ -34,34 +42,64 @@ static struct dma_map_ops xen_swiotlb_dma_ops = {
 int __init pci_xen_swiotlb_detect(void)
 {
 
+        if (!xen_pv_domain())
+                return 0;
+
         /* If running as PV guest, either iommu=soft, or swiotlb=force will
          * activate this IOMMU. If running as PV privileged, activate it
          * irregardless.
          */
-        if ((xen_initial_domain() || swiotlb || swiotlb_force) &&
-            (xen_pv_domain()))
+        if ((xen_initial_domain() || swiotlb || swiotlb_force))
                 xen_swiotlb = 1;
 
         /* If we are running under Xen, we MUST disable the native SWIOTLB.
          * Don't worry about swiotlb_force flag activating the native, as
          * the 'swiotlb' flag is the only one turning it on. */
-        if (xen_pv_domain())
-                swiotlb = 0;
+        swiotlb = 0;
 
+#ifdef CONFIG_X86_64
+        /* pci_swiotlb_detect_4gb turns on native SWIOTLB if no_iommu == 0
+         * (so no iommu=X command line over-writes).
+         * Considering that PV guests do not want the *native SWIOTLB* but
+         * only Xen SWIOTLB it is not useful to us so set no_iommu=1 here.
+         */
+        if (max_pfn > MAX_DMA32_PFN)
+                no_iommu = 1;
+#endif
         return xen_swiotlb;
 }
 
 void __init pci_xen_swiotlb_init(void)
 {
         if (xen_swiotlb) {
-                xen_swiotlb_init(1);
+                xen_swiotlb_init(1, true /* early */);
                 dma_ops = &xen_swiotlb_dma_ops;
 
                 /* Make sure ACS will be enabled */
                 pci_request_acs();
         }
 }
+
+int pci_xen_swiotlb_init_late(void)
+{
+        int rc;
+
+        if (xen_swiotlb)
+                return 0;
+
+        rc = xen_swiotlb_init(1, false /* late */);
+        if (rc)
+                return rc;
+
+        dma_ops = &xen_swiotlb_dma_ops;
+        /* Make sure ACS will be enabled */
+        pci_request_acs();
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
+
 IOMMU_INIT_FINISH(pci_xen_swiotlb_detect,
-                  0,
+                  NULL,
                   pci_xen_swiotlb_init,
-                  0);
+                  NULL);