[Qemu-devel] [PATCH qemu v13 08/16] memory: Add reporting of supported page sizes

[Alexey Kardashevskiy <aik@ozlabs.ru>]

Every IOMMU has some granularity which MemoryRegionIOMMUOps::translate
uses when translating, however this information is not available outside
the translate context for various checks.

This adds a get_page_sizes callback to MemoryRegionIOMMUOps and
a wrapper for it so IOMMU users (such as VFIO) can know the actual
page size(s) used by an IOMMU.

The qemu_real_host_page_mask is used as fallback.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v4:
* s/1<<TARGET_PAGE_BITS/qemu_real_host_page_size/
---
 hw/ppc/spapr_iommu.c  |  8 ++++++++
 include/exec/memory.h | 11 +++++++++++
 memory.c              |  9 +++++++++
 3 files changed, 28 insertions(+)

diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c
index 67a8356..4c52cf4 100644
--- a/hw/ppc/spapr_iommu.c
+++ b/hw/ppc/spapr_iommu.c
@@ -143,6 +143,13 @@ static int spapr_tce_vfio_notify(MemoryRegion *iommu, bool attached)
     return spapr_tce_vfio_notify_owner(tcet->owner, tcet, attached);
 }
 
+static uint64_t spapr_tce_get_page_sizes(MemoryRegion *iommu)
+{
+    sPAPRTCETable *tcet = container_of(iommu, sPAPRTCETable, iommu);
+
+    return 1ULL << tcet->page_shift;
+}
+
 static int spapr_tce_table_post_load(void *opaque, int version_id)
 {
     sPAPRTCETable *tcet = SPAPR_TCE_TABLE(opaque);
@@ -175,6 +182,7 @@ static const VMStateDescription vmstate_spapr_tce_table = {
 static MemoryRegionIOMMUOps spapr_iommu_ops = {
     .translate = spapr_tce_translate_iommu,
     .vfio_notify = spapr_tce_vfio_notify,
+    .get_page_sizes = spapr_tce_get_page_sizes,
 };
 
 static int spapr_tce_table_realize(DeviceState *dev)
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 9f82629..c34e67c 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -152,6 +152,8 @@ struct MemoryRegionIOMMUOps {
     IOMMUTLBEntry (*translate)(MemoryRegion *iommu, hwaddr addr, bool is_write);
     /* Called when VFIO starts/stops using this */
     int (*vfio_notify)(MemoryRegion *iommu, bool attached);
+    /* Returns supported page sizes */
+    uint64_t (*get_page_sizes)(MemoryRegion *iommu);
 };
 
 typedef struct CoalescedMemoryRange CoalescedMemoryRange;
@@ -576,6 +578,15 @@ static inline bool memory_region_is_iommu(MemoryRegion *mr)
 
 
 /**
+ * memory_region_iommu_get_page_sizes: get supported page sizes in an iommu
+ *
+ * Returns %bitmap of supported page sizes for an iommu.
+ *
+ * @mr: the memory region being queried
+ */
+uint64_t memory_region_iommu_get_page_sizes(MemoryRegion *mr);
+
+/**
  * memory_region_notify_iommu: notify a change in an IOMMU translation entry.
  *
  * @mr: the memory region that was changed
diff --git a/memory.c b/memory.c
index 0dd9695..5d8453d 100644
--- a/memory.c
+++ b/memory.c
@@ -1462,6 +1462,15 @@ void memory_region_notify_iommu(MemoryRegion *mr,
     notifier_list_notify(&mr->iommu_notify, &entry);
 }
 
+uint64_t memory_region_iommu_get_page_sizes(MemoryRegion *mr)
+{
+    assert(memory_region_is_iommu(mr));
+    if (mr->iommu_ops && mr->iommu_ops->get_page_sizes) {
+        return mr->iommu_ops->get_page_sizes(mr);
+    }
+    return qemu_real_host_page_size;
+}
+
 void memory_region_set_log(MemoryRegion *mr, bool log, unsigned client)
 {
     uint8_t mask = 1 << client;
-- 
2.5.0.rc3