[v11,07/10] memory: Add interface to set iommu page size mask

Commit Message

Jean-Philippe Brucker Oct. 30, 2020, 6:05 p.m. UTC

From: Bharat Bhushan <[e-mail]>

Allow to set the page size mask supported by an iommu memory region.
This enables a vIOMMU to communicate the page size granule supported by
an assigned device, on hosts that use page sizes greater than 4kB.

Acked-by: Peter Xu <[e-mail]>
Reviewed-by: Eric Auger <[e-mail]>
Signed-off-by: Bharat Bhushan <[e-mail]>
Signed-off-by: Jean-Philippe Brucker <[e-mail]>
---
v11: improve comment
---
 include/exec/memory.h | 38 ++++++++++++++++++++++++++++++++++++++
 softmmu/memory.c      | 13 +++++++++++++
 2 files changed, 51 insertions(+)

Patch

diff --git a/include/exec/memory.h b/include/exec/memory.h
index aff6ef76053..0f3e6bcd5e7 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -397,6 +397,32 @@  struct IOMMUMemoryRegionClass {
      * @iommu: the IOMMUMemoryRegion
      */
     int (*num_indexes)(IOMMUMemoryRegion *iommu);
+
+    /**
+     * @iommu_set_page_size_mask:
+     *
+     * Restrict the page size mask that can be supported with a given IOMMU
+     * memory region. Used for example to propagate host physical IOMMU page
+     * size mask limitations to the virtual IOMMU.
+     *
+     * Optional method: if this method is not provided, then the default global
+     * page mask is used.
+     *
+     * @iommu: the IOMMUMemoryRegion
+     *
+     * @page_size_mask: a bitmask of supported page sizes. At least one bit,
+     * representing the smallest page size, must be set. Additional set bits
+     * represent supported block sizes. For example a host physical IOMMU that
+     * uses page tables with a page size of 4kB, and supports 2MB and 4GB
+     * blocks, will set mask 0x40201000. A granule of 4kB with indiscriminate
+     * block sizes is specified with mask 0xfffffffffffff000.
+     *
+     * Returns 0 on success, or a negative error. In case of failure, the error
+     * object must be created.
+     */
+     int (*iommu_set_page_size_mask)(IOMMUMemoryRegion *iommu,
+                                     uint64_t page_size_mask,
+                                     Error **errp);
 };
 
 typedef struct CoalescedMemoryRange CoalescedMemoryRange;
@@ -1409,6 +1435,18 @@  int memory_region_iommu_attrs_to_index(IOMMUMemoryRegion *iommu_mr,
  */
 int memory_region_iommu_num_indexes(IOMMUMemoryRegion *iommu_mr);
 
+/**
+ * memory_region_iommu_set_page_size_mask: set the supported page
+ * sizes for a given IOMMU memory region
+ *
+ * @iommu_mr: IOMMU memory region
+ * @page_size_mask: supported page size mask
+ * @errp: pointer to Error*, to store an error if it happens.
+ */
+int memory_region_iommu_set_page_size_mask(IOMMUMemoryRegion *iommu_mr,
+                                           uint64_t page_size_mask,
+                                           Error **errp);
+
 /**
  * memory_region_name: get a memory region's name
  *
diff --git a/softmmu/memory.c b/softmmu/memory.c
index ee4a6bc1685..bb40d2a1d8b 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -1841,6 +1841,19 @@  static int memory_region_update_iommu_notify_flags(IOMMUMemoryRegion *iommu_mr,
     return ret;
 }
 
+int memory_region_iommu_set_page_size_mask(IOMMUMemoryRegion *iommu_mr,
+                                           uint64_t page_size_mask,
+                                           Error **errp)
+{
+    IOMMUMemoryRegionClass *imrc = IOMMU_MEMORY_REGION_GET_CLASS(iommu_mr);
+    int ret = 0;
+
+    if (imrc->iommu_set_page_size_mask) {
+        ret = imrc->iommu_set_page_size_mask(iommu_mr, page_size_mask, errp);
+    }
+    return ret;
+}
+
 int memory_region_register_iommu_notifier(MemoryRegion *mr,
                                           IOMMUNotifier *n, Error **errp)
 {