[PATCH v1 07/10] iommu/arm: Add alloc_page_table platform callback

[Oleksandr Tyshchenko <olekstysh@gmail.com>]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

The alloc_page_table callback is a mandatory thing
for the IOMMUs that don't share page table with the CPU on ARM.
The non-shared IOMMUs have to perform all required actions here
to be ready to handle IOMMU mapping updates right after completing it.

The arch_iommu_populate_page_table() seems an appropriate place
to call newly created callback.
Since we will only be here for the non-shared IOMMUs always
return error if the callback wasn't implemented.

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

---
   Changes in V1:
      - Wrap callback in #ifdef CONFIG_ARM.
---
 xen/drivers/passthrough/arm/iommu.c | 5 +++--
 xen/include/xen/iommu.h             | 3 +++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/xen/drivers/passthrough/arm/iommu.c b/xen/drivers/passthrough/arm/iommu.c
index 95b1abb..f132032 100644
--- a/xen/drivers/passthrough/arm/iommu.c
+++ b/xen/drivers/passthrough/arm/iommu.c
@@ -70,6 +70,7 @@ void arch_iommu_domain_destroy(struct domain *d)
 
 int arch_iommu_populate_page_table(struct domain *d)
 {
-    /* The IOMMU shares the p2m with the CPU */
-    return -ENOSYS;
+    const struct iommu_ops *ops = iommu_get_ops();
+
+    return ops->alloc_page_table ? ops->alloc_page_table(d) : -ENOSYS;
 }
diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index 3afbc3b..f5914db 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -175,6 +175,9 @@ struct iommu_ops {
                                   unsigned int flags);
     int __must_check (*unmap_pages)(struct domain *d, unsigned long gfn,
                                     unsigned int order);
+#ifdef CONFIG_ARM
+    int (*alloc_page_table)(struct domain *d);
+#endif /* CONFIG_ARM */
     void (*free_page_table)(struct page_info *);
 #ifdef CONFIG_X86
     void (*update_ire_from_apic)(unsigned int apic, unsigned int reg, unsigned int value);
-- 
2.7.4


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