[PATCH v1 06/10] iommu: Add extra use_iommu argument to iommu_domain_init()

[Oleksandr Tyshchenko <olekstysh@gmail.com>]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

The presence of this flag lets us know that the guest
has devices which will most likely be used for passthrough
and as the result the use of IOMMU is expected for this domain.
In that case we have to call iommu_construct(), actually
what the real assign_device call usually does.

As iommu_domain_init() is called with use_iommu flag being forced
to false for now, no functional change is intended for both ARM and x86.

Basically, this patch is needed for non-shared IOMMUs on ARM only
since the non-shared IOMMUs on x86 are ok if iommu_construct() is called
later. But, in order to be more generic and for possible future optimization
make this change appliable for both platforms.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
CC: Jan Beulich <jbeulich@suse.com>

---
   Changes in v1:
      - Clarify patch subject/description.
      - s/bool_t/bool/
---
 xen/arch/arm/domain.c           |  2 +-
 xen/arch/x86/domain.c           |  2 +-
 xen/drivers/passthrough/iommu.c | 11 +++++++++--
 xen/include/xen/iommu.h         |  2 +-
 4 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 76310ed..ec19310 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -569,7 +569,7 @@ int arch_domain_create(struct domain *d, unsigned int domcr_flags,
     ASSERT(config != NULL);
 
     /* p2m_init relies on some value initialized by the IOMMU subsystem */
-    if ( (rc = iommu_domain_init(d)) != 0 )
+    if ( (rc = iommu_domain_init(d, false)) != 0 )
         goto fail;
 
     if ( (rc = p2m_init(d)) != 0 )
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 90e2b1f..54037af 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -641,7 +641,7 @@ int arch_domain_create(struct domain *d, unsigned int domcr_flags,
         if ( (rc = init_domain_irq_mapping(d)) != 0 )
             goto fail;
 
-        if ( (rc = iommu_domain_init(d)) != 0 )
+        if ( (rc = iommu_domain_init(d, false)) != 0 )
             goto fail;
     }
     spin_lock_init(&d->arch.e820_lock);
diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index 3e9e4c3..c85f7b4 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -129,7 +129,7 @@ static void __init parse_iommu_param(char *s)
     } while ( ss );
 }
 
-int iommu_domain_init(struct domain *d)
+int iommu_domain_init(struct domain *d, bool use_iommu)
 {
     struct domain_iommu *hd = dom_iommu(d);
     int ret = 0;
@@ -142,7 +142,14 @@ int iommu_domain_init(struct domain *d)
         return 0;
 
     hd->platform_ops = iommu_get_ops();
-    return hd->platform_ops->init(d);
+    ret = hd->platform_ops->init(d);
+    if ( ret )
+        return ret;
+
+    if ( use_iommu && !is_hardware_domain(d) )
+        ret = iommu_construct(d);
+
+    return ret;
 }
 
 static void __hwdom_init check_hwdom_reqs(struct domain *d)
diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index 3297998..3afbc3b 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -56,7 +56,7 @@ int iommu_setup(void);
 int iommu_add_device(struct pci_dev *pdev);
 int iommu_enable_device(struct pci_dev *pdev);
 int iommu_remove_device(struct pci_dev *pdev);
-int iommu_domain_init(struct domain *d);
+int iommu_domain_init(struct domain *d, bool use_iommu);
 void iommu_hwdom_init(struct domain *d);
 void iommu_domain_destroy(struct domain *d);
 int deassign_device(struct domain *d, u16 seg, u8 bus, u8 devfn);
-- 
2.7.4


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