s390x/pci: fixup global refresh

The VFIO common code doesn't provide the possibility to modify a
previous mapping entry in another way than unmapping and mapping again
with new properties.

To avoid -EEXIST DMA mapping error, we introduce a GHashTable to store
S390IOTLBEntry instances in order to cache the mapped entries. When
intercepting rpcit instruction, ignore the identical mapped entries to
avoid doing map operations multiple times and do unmap and re-map
operations for the case of updating the valid entries.

Acked-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: Yi Min Zhao <zyimin@linux.vnet.ibm.com>
Message-Id: <20180205072258.5968-3-zyimin@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

1 files changed, 17 insertions, 7 deletions

diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
index e7ef7d2..77a50ca 100644
--- a/hw/s390x/s390-pci-bus.c
+++ b/hw/s390x/s390-pci-bus.c
@@ -487,7 +487,8 @@ static IOMMUTLBEntry s390_translate_iommu(IOMMUMemoryRegion *mr, hwaddr addr,
                                           IOMMUAccessFlags flag)
 {
     S390PCIIOMMU *iommu = container_of(mr, S390PCIIOMMU, iommu_mr);
-    S390IOTLBEntry entry;
+    S390IOTLBEntry *entry;
+    uint64_t iova = addr & PAGE_MASK;
     uint16_t error = 0;
     IOMMUTLBEntry ret = {
         .target_as = &address_space_memory,
@@ -515,12 +516,17 @@ static IOMMUTLBEntry s390_translate_iommu(IOMMUMemoryRegion *mr, hwaddr addr,
         goto err;
     }
 
-    error = s390_guest_io_table_walk(iommu->g_iota, addr, &entry);
-
-    ret.iova = entry.iova;
-    ret.translated_addr = entry.translated_addr;
-    ret.addr_mask = entry.len - 1;
-    ret.perm = entry.perm;
+    entry = g_hash_table_lookup(iommu->iotlb, &iova);
+    if (entry) {
+        ret.iova = entry->iova;
+        ret.translated_addr = entry->translated_addr;
+        ret.addr_mask = entry->len - 1;
+        ret.perm = entry->perm;
+    } else {
+        ret.iova = iova;
+        ret.addr_mask = ~PAGE_MASK;
+        ret.perm = IOMMU_NONE;
+    }
 
     if (flag != IOMMU_NONE && !(flag & ret.perm)) {
         error = ERR_EVENT_TPROTE;
@@ -572,6 +578,8 @@ static S390PCIIOMMU *s390_pci_get_iommu(S390pciState *s, PCIBus *bus,
                                         PCI_FUNC(devfn));
         memory_region_init(&iommu->mr, OBJECT(iommu), mr_name, UINT64_MAX);
         address_space_init(&iommu->as, &iommu->mr, as_name);
+        iommu->iotlb = g_hash_table_new_full(g_int64_hash, g_int64_equal,
+                                             NULL, g_free);
         table->iommu[PCI_SLOT(devfn)] = iommu;
 
         g_free(mr_name);
@@ -661,6 +669,7 @@ void s390_pci_iommu_enable(S390PCIIOMMU *iommu)
 void s390_pci_iommu_disable(S390PCIIOMMU *iommu)
 {
     iommu->enabled = false;
+    g_hash_table_remove_all(iommu->iotlb);
     memory_region_del_subregion(&iommu->mr, MEMORY_REGION(&iommu->iommu_mr));
     object_unparent(OBJECT(&iommu->iommu_mr));
 }
@@ -676,6 +685,7 @@ static void s390_pci_iommu_free(S390pciState *s, PCIBus *bus, int32_t devfn)
     }
 
     table->iommu[PCI_SLOT(devfn)] = NULL;
+    g_hash_table_destroy(iommu->iotlb);
     address_space_destroy(&iommu->as);
     object_unparent(OBJECT(&iommu->mr));
     object_unparent(OBJECT(iommu));