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>
master commit: 834c97baebb3743c54bcae228e984ae1b9692e6a
master date: 2016-06-14 15:10:57 +0200

diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index f2841de27f91c8e852989116b1fadb4f97152b39..5af95ce0a04bbc550fb52a1814c9cd07da0401fa 100644 (file)
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -200,21 +200,47 @@ 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)