vfio: return mr from vfio_get_xlat_addr

Modify memory_get_xlat_addr and vfio_get_xlat_addr to return the memory
region that the translated address is found in.  This will be needed by
CPR in a subsequent patch to map blocks using IOMMU_IOAS_MAP_FILE.

Also return the xlat offset, so we can simplify the interface by removing
the out parameters that can be trivially derived from mr and xlat.

Lastly, rename the functions to  to memory_translate_iotlb() and
vfio_translate_iotlb().

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: John Levon <john.levon@nutanix.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Link: https://lore.kernel.org/qemu-devel/1747661203-136490-1-git-send-email-steven.sistare@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>

2 files changed, 29 insertions, 13 deletions

diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c
index bfacb3d..38e3dc8 100644
--- a/hw/vfio/listener.c
+++ b/hw/vfio/listener.c
@@ -90,16 +90,17 @@ static bool vfio_listener_skipped_section(MemoryRegionSection *section)
            section->offset_within_address_space & (1ULL << 63);
 }
 
-/* Called with rcu_read_lock held.  */
-static bool vfio_get_xlat_addr(IOMMUTLBEntry *iotlb, void **vaddr,
-                               ram_addr_t *ram_addr, bool *read_only,
-                               Error **errp)
+/*
+ * Called with rcu_read_lock held.
+ * The returned MemoryRegion must not be accessed after calling rcu_read_unlock.
+ */
+static MemoryRegion *vfio_translate_iotlb(IOMMUTLBEntry *iotlb, hwaddr *xlat_p,
+                                          Error **errp)
 {
-    bool ret, mr_has_discard_manager;
+    MemoryRegion *mr;
 
-    ret = memory_get_xlat_addr(iotlb, vaddr, ram_addr, read_only,
-                               &mr_has_discard_manager, errp);
-    if (ret && mr_has_discard_manager) {
+    mr = memory_translate_iotlb(iotlb, xlat_p, errp);
+    if (mr && memory_region_has_ram_discard_manager(mr)) {
         /*
          * Malicious VMs might trigger discarding of IOMMU-mapped memory. The
          * pages will remain pinned inside vfio until unmapped, resulting in a
@@ -118,7 +119,7 @@ static bool vfio_get_xlat_addr(IOMMUTLBEntry *iotlb, void **vaddr,
                          " intended via an IOMMU. It's possible to mitigate "
                          " by setting/adjusting RLIMIT_MEMLOCK.");
     }
-    return ret;
+    return mr;
 }
 
 static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
@@ -126,6 +127,8 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
     VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n);
     VFIOContainerBase *bcontainer = giommu->bcontainer;
     hwaddr iova = iotlb->iova + giommu->iommu_offset;
+    MemoryRegion *mr;
+    hwaddr xlat;
     void *vaddr;
     int ret;
     Error *local_err = NULL;
@@ -150,10 +153,14 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
     if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
         bool read_only;
 
-        if (!vfio_get_xlat_addr(iotlb, &vaddr, NULL, &read_only, &local_err)) {
+        mr = vfio_translate_iotlb(iotlb, &xlat, &local_err);
+        if (!mr) {
             error_report_err(local_err);
             goto out;
         }
+        vaddr = memory_region_get_ram_ptr(mr) + xlat;
+        read_only = !(iotlb->perm & IOMMU_WO) || mr->readonly;
+
         /*
          * vaddr is only valid until rcu_read_unlock(). But after
          * vfio_dma_map has set up the mapping the pages will be
@@ -1010,6 +1017,8 @@ static void vfio_iommu_map_dirty_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
     ram_addr_t translated_addr;
     Error *local_err = NULL;
     int ret = -EINVAL;
+    MemoryRegion *mr;
+    hwaddr xlat;
 
     trace_vfio_iommu_map_dirty_notify(iova, iova + iotlb->addr_mask);
 
@@ -1021,9 +1030,11 @@ static void vfio_iommu_map_dirty_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
     }
 
     rcu_read_lock();
-    if (!vfio_get_xlat_addr(iotlb, NULL, &translated_addr, NULL, &local_err)) {
+    mr = vfio_translate_iotlb(iotlb, &xlat, &local_err);
+    if (!mr) {
         goto out_unlock;
     }
+    translated_addr = memory_region_get_ram_addr(mr) + xlat;
 
     ret = vfio_container_query_dirty_bitmap(bcontainer, iova, iotlb->addr_mask + 1,
                                 translated_addr, &local_err);
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index e20da95..7061b6e 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -209,6 +209,8 @@ static void vhost_vdpa_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
     int ret;
     Int128 llend;
     Error *local_err = NULL;
+    MemoryRegion *mr;
+    hwaddr xlat;
 
     if (iotlb->target_as != &address_space_memory) {
         error_report("Wrong target AS \"%s\", only system memory is allowed",
@@ -228,11 +230,14 @@ static void vhost_vdpa_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
     if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
         bool read_only;
 
-        if (!memory_get_xlat_addr(iotlb, &vaddr, NULL, &read_only, NULL,
-                                  &local_err)) {
+        mr = memory_translate_iotlb(iotlb, &xlat, &local_err);
+        if (!mr) {
             error_report_err(local_err);
             return;
         }
+        vaddr = memory_region_get_ram_ptr(mr) + xlat;
+        read_only = !(iotlb->perm & IOMMU_WO) || mr->readonly;
+
         ret = vhost_vdpa_dma_map(s, VHOST_VDPA_GUEST_PA_ASID, iova,
                                  iotlb->addr_mask + 1, vaddr, read_only);
         if (ret) {