IOMMU: handle IOMMU mapping and unmapping failures

Treat IOMMU mapping and unmapping failures as a fatal to the DomU
If IOMMU mapping and unmapping failed, crash the DomU and propagate
the error up to the call trees.

No spamming of the log can occur. For DomU, we avoid logging any
message for already dying domains. For Dom0, that'll still be more
verbose than we'd really like, but it at least wouldn't outright
flood the console.

Signed-off-by: Quan Xu <quan.xu@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index 9d104d28a4e37dffe7b44c4de7af32f8f6a8e80a..673e1262058b9d5f60a9bc6696e15a4046560012 100644 (file)
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -240,21 +240,47 @@ int iommu_map_page(struct domain *d, unsigned long gfn, unsigned long mfn,
                    unsigned int flags)
 {
     const struct domain_iommu *hd = dom_iommu(d);
+    int rc;
 
     if ( !iommu_enabled || !hd->platform_ops )
         return 0;
 
-    return hd->platform_ops->map_page(d, gfn, mfn, flags);
+    rc = hd->platform_ops->map_page(d, gfn, mfn, flags);
+    if ( unlikely(rc) )
+    {
+        if ( !d->is_shutting_down && printk_ratelimit() )
+            printk(XENLOG_ERR
+                   "d%d: IOMMU mapping gfn %#lx to mfn %#lx failed: %d\n",
+                   d->domain_id, gfn, mfn, rc);
+
+        if ( !is_hardware_domain(d) )
+            domain_crash(d);
+    }
+
+    return rc;
 }
 
 int iommu_unmap_page(struct domain *d, unsigned long gfn)
 {
     const struct domain_iommu *hd = dom_iommu(d);
+    int rc;
 
     if ( !iommu_enabled || !hd->platform_ops )
         return 0;
 
-    return hd->platform_ops->unmap_page(d, gfn);
+    rc = hd->platform_ops->unmap_page(d, gfn);
+    if ( unlikely(rc) )
+    {
+        if ( !d->is_shutting_down && printk_ratelimit() )
+            printk(XENLOG_ERR
+                   "d%d: IOMMU unmapping gfn %#lx failed: %d\n",
+                   d->domain_id, gfn, rc);
+
+        if ( !is_hardware_domain(d) )
+            domain_crash(d);
+    }
+
+    return rc;
 }
 
 static void iommu_free_pagetables(unsigned long unused)