[Xen-devel] [PATCH v4 02/10] IOMMU: handle IOMMU mapping and unmapping failures

[Quan Xu <quan.xu@xxxxxxxxx>]

Treat IOMMU mapping and unmapping failures as a fatal to the domain
(with the exception of the hardware domain).

If IOMMU mapping and unmapping failed, crash the domain (with the
exception of the hardware domain) and propagate the error up to the
call trees.

Signed-off-by: Quan Xu <quan.xu@xxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>

CC: Jan Beulich <jbeulich@xxxxxxxx>
CC: Kevin Tian <kevin.tian@xxxxxxxxx>
---
 xen/drivers/passthrough/iommu.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index c59b2ab..09560c0 100644
--- 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) )
+    {
+        printk(XENLOG_ERR
+               "iommu_map_page: IOMMU mapping gfn %#lx mfn %#lx failed for 
dom%d.",
+               gfn, mfn, d->domain_id);
+
+        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) )
+    {
+        printk(XENLOG_ERR
+               "iommu_unmap_page: IOMMU unmapping gfn %#lx failed for dom%d.",
+               gfn, d->domain_id);
+
+        if ( !is_hardware_domain(d) )
+            domain_crash(d);
+    }
+
+    return rc;
 }
 
 static void iommu_free_pagetables(unsigned long unused)
-- 
1.9.1


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