[PATCH v2 09/20] amd_iommu: Add basic structure to support IOMMU notifier updates

[Alejandro Jimenez <alejandro.j.jimenez@oracle.com>]

Add the minimal data structures required to maintain a list of address
spaces (i.e. devices) with registered notifiers, and to update the type of
events that require notifications.
Note that the ability to register for MAP notifications is not available.
It will be unblocked by following changes that enable the synchronization of
guest I/O page tables with host IOMMU state, at which point an amd-iommu
device property will be introduced to control this capability.

Signed-off-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
---
 hw/i386/amd_iommu.c | 26 +++++++++++++++++++++++---
 hw/i386/amd_iommu.h |  3 +++
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
index 6a2ba878dfa7..2f69459ab68d 100644
--- a/hw/i386/amd_iommu.c
+++ b/hw/i386/amd_iommu.c
@@ -66,6 +66,11 @@ struct AMDVIAddressSpace {
     MemoryRegion iommu_nodma;   /* Alias of shared nodma memory region  */
     MemoryRegion iommu_ir;      /* Device's interrupt remapping region  */
     AddressSpace as;            /* device's corresponding address space */
+
+    /* DMA address translation support */
+    IOMMUNotifierFlag notifier_flags;
+    /* entry in list of Address spaces with registered notifiers */
+    QLIST_ENTRY(AMDVIAddressSpace) next;
 };
 
 /* AMDVI cache entry */
@@ -1711,6 +1716,7 @@ static AddressSpace *amdvi_host_dma_iommu(PCIBus *bus, void *opaque, int devfn)
         iommu_as[devfn]->bus_num = (uint8_t)bus_num;
         iommu_as[devfn]->devfn = (uint8_t)devfn;
         iommu_as[devfn]->iommu_state = s;
+        iommu_as[devfn]->notifier_flags = IOMMU_NONE;
 
         amdvi_dev_as = iommu_as[devfn];
 
@@ -1791,14 +1797,28 @@ static int amdvi_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu,
                                            Error **errp)
 {
     AMDVIAddressSpace *as = container_of(iommu, AMDVIAddressSpace, iommu);
+    AMDVIState *s = as->iommu_state;
 
     if (new & IOMMU_NOTIFIER_MAP) {
         error_setg(errp,
-                   "device %02x.%02x.%x requires iommu notifier which is not "
-                   "currently supported", as->bus_num, PCI_SLOT(as->devfn),
-                   PCI_FUNC(as->devfn));
+                "device %02x.%02x.%x requires iommu notifier which is not "
+                "currently supported", as->bus_num, PCI_SLOT(as->devfn),
+                PCI_FUNC(as->devfn));
         return -EINVAL;
     }
+
+    /*
+     * Update notifier flags for address space and the list of address spaces
+     * with registered notifiers.
+     */
+    as->notifier_flags = new;
+
+    if (old == IOMMU_NOTIFIER_NONE) {
+        QLIST_INSERT_HEAD(&s->amdvi_as_with_notifiers, as, next);
+    } else if (new == IOMMU_NOTIFIER_NONE) {
+        QLIST_REMOVE(as, next);
+    }
+
     return 0;
 }
 
diff --git a/hw/i386/amd_iommu.h b/hw/i386/amd_iommu.h
index 5e35d4b15167..a7462b2adb79 100644
--- a/hw/i386/amd_iommu.h
+++ b/hw/i386/amd_iommu.h
@@ -411,6 +411,9 @@ struct AMDVIState {
     /* for each served device */
     AMDVIAddressSpace **address_spaces[PCI_BUS_MAX];
 
+    /* list of address spaces with registered notifiers */
+    QLIST_HEAD(, AMDVIAddressSpace) amdvi_as_with_notifiers;
+
     /* IOTLB */
     GHashTable *iotlb;
 
-- 
2.43.5