[PATCH v3 11/13] xen/arm: Don't give IOMMU devices to dom0 when iommu is disabled

[Julien Grall <julien.grall@linaro.org>]

When iommu={disable,off,no,false} is given to Xen command line, the IOMMU
framework won't specify that the device shouldn't be passthrough to DOM0.

Signed-off-by: Julien Grall <julien.grall@linaro.org>

---
    Changes in v2:
        - Patch added
---
 xen/arch/arm/device.c        |   15 +++++++++++++++
 xen/arch/arm/domain_build.c  |   10 ++++++++++
 xen/include/asm-arm/device.h |   10 ++++++++++
 3 files changed, 35 insertions(+)

diff --git a/xen/arch/arm/device.c b/xen/arch/arm/device.c
index f86b2e3..59e94c0 100644
--- a/xen/arch/arm/device.c
+++ b/xen/arch/arm/device.c
@@ -67,6 +67,21 @@ int __init device_init(struct dt_device_node *dev, enum device_type type,
     return -EBADF;
 }
 
+enum device_type device_get_type(const struct dt_device_node *dev)
+{
+    const struct device_desc *desc;
+
+    ASSERT(dev != NULL);
+
+    for ( desc = _sdevice; desc != _edevice; desc++ )
+    {
+        if ( device_is_compatible(desc, dev) )
+            return desc->type;
+    }
+
+    return DEVICE_UNKNOWN;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 229954b..2438aa0 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -11,6 +11,7 @@
 #include <xen/device_tree.h>
 #include <xen/libfdt/libfdt.h>
 #include <xen/guest_access.h>
+#include <asm/device.h>
 #include <asm/setup.h>
 #include <asm/platform.h>
 #include <asm/psci.h>
@@ -822,6 +823,15 @@ static int handle_node(struct domain *d, struct kernel_info *kinfo,
         return 0;
     }
 
+    /* Even if the IOMMU device is not used by Xen, it should not be
+     * passthrough to DOM0
+     */
+    if ( device_get_type(node) == DEVICE_IOMMU )
+    {
+        DPRINT(" IOMMU, skip it\n");
+        return 0;
+    }
+
     /*
      * Some device doesn't need to be mapped in Xen:
      *  - Memory: the guest will see a different view of memory. It will
diff --git a/xen/include/asm-arm/device.h b/xen/include/asm-arm/device.h
index ed04344..60109cc 100644
--- a/xen/include/asm-arm/device.h
+++ b/xen/include/asm-arm/device.h
@@ -8,6 +8,8 @@ enum device_type
 {
     DEVICE_SERIAL,
     DEVICE_IOMMU,
+    /* Use for error */
+    DEVICE_UNKNOWN,
 };
 
 struct device_desc {
@@ -32,6 +34,14 @@ struct device_desc {
 int __init device_init(struct dt_device_node *dev, enum device_type type,
                        const void *data);
 
+/**
+ * device_get_type - Get the type of the device
+ * @dev: device to match
+ *
+ * Return the device type on success or DEVICE_ANY on failure
+ */
+enum device_type device_get_type(const struct dt_device_node *dev);
+
 #define DT_DEVICE_START(_name, _namestr, _type)                     \
 static const struct device_desc __dev_desc_##_name __used           \
 __attribute__((__section__(".dev.info"))) = {                       \
-- 
1.7.10.4