vfio: Generalize region support

Both platform and PCI vfio drivers create a "slow", I/O memory region
with one or more mmap memory regions overlayed when supported by the
device. Generalize this to a set of common helpers in the core that
pulls the region info from vfio, fills the region data, configures
slow mapping, and adds helpers for comleting the mmap, enable/disable,
and teardown.  This can be immediately used by the PCI MSI-X code,
which needs to mmap around the MSI-X vector table.

This also changes VFIORegion.mem to be dynamically allocated because
otherwise we don't know how the caller has allocated VFIORegion and
therefore don't know whether to unreference it to destroy the
MemoryRegion or not.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 144 insertions, 28 deletions

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index e20fc4f794..96ccb797fe 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -493,46 +493,162 @@ static void vfio_listener_release(VFIOContainer *container)
     memory_listener_unregister(&container->listener);
 }
 
-int vfio_mmap_region(Object *obj, VFIORegion *region,
-                     MemoryRegion *mem, MemoryRegion *submem,
-                     void **map, size_t size, off_t offset,
-                     const char *name)
+int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region,
+                      int index, const char *name)
 {
-    int ret = 0;
-    VFIODevice *vbasedev = region->vbasedev;
+    struct vfio_region_info *info;
+    int ret;
+
+    ret = vfio_get_region_info(vbasedev, index, &info);
+    if (ret) {
+        return ret;
+    }
+
+    region->vbasedev = vbasedev;
+    region->flags = info->flags;
+    region->size = info->size;
+    region->fd_offset = info->offset;
+    region->nr = index;
 
-    if (!vbasedev->no_mmap && size && region->flags &
-        VFIO_REGION_INFO_FLAG_MMAP) {
-        int prot = 0;
+    if (region->size) {
+        region->mem = g_new0(MemoryRegion, 1);
+        memory_region_init_io(region->mem, obj, &vfio_region_ops,
+                              region, name, region->size);
 
-        if (region->flags & VFIO_REGION_INFO_FLAG_READ) {
-            prot |= PROT_READ;
+        if (!vbasedev->no_mmap &&
+            region->flags & VFIO_REGION_INFO_FLAG_MMAP &&
+            !(region->size & ~qemu_real_host_page_mask)) {
+
+            region->nr_mmaps = 1;
+            region->mmaps = g_new0(VFIOMmap, region->nr_mmaps);
+
+            region->mmaps[0].offset = 0;
+            region->mmaps[0].size = region->size;
         }
+    }
+
+    g_free(info);
+
+    trace_vfio_region_setup(vbasedev->name, index, name,
+                            region->flags, region->fd_offset, region->size);
+    return 0;
+}
 
-        if (region->flags & VFIO_REGION_INFO_FLAG_WRITE) {
-            prot |= PROT_WRITE;
+int vfio_region_mmap(VFIORegion *region)
+{
+    int i, prot = 0;
+    char *name;
+
+    if (!region->mem) {
+        return 0;
+    }
+
+    prot |= region->flags & VFIO_REGION_INFO_FLAG_READ ? PROT_READ : 0;
+    prot |= region->flags & VFIO_REGION_INFO_FLAG_WRITE ? PROT_WRITE : 0;
+
+    for (i = 0; i < region->nr_mmaps; i++) {
+        region->mmaps[i].mmap = mmap(NULL, region->mmaps[i].size, prot,
+                                     MAP_SHARED, region->vbasedev->fd,
+                                     region->fd_offset +
+                                     region->mmaps[i].offset);
+        if (region->mmaps[i].mmap == MAP_FAILED) {
+            int ret = -errno;
+
+            trace_vfio_region_mmap_fault(memory_region_name(region->mem), i,
+                                         region->fd_offset +
+                                         region->mmaps[i].offset,
+                                         region->fd_offset +
+                                         region->mmaps[i].offset +
+                                         region->mmaps[i].size - 1, ret);
+
+            region->mmaps[i].mmap = NULL;
+
+            for (i--; i >= 0; i--) {
+                memory_region_del_subregion(region->mem, &region->mmaps[i].mem);
+                munmap(region->mmaps[i].mmap, region->mmaps[i].size);
+                object_unparent(OBJECT(&region->mmaps[i].mem));
+                region->mmaps[i].mmap = NULL;
+            }
+
+            return ret;
         }
 
-        *map = mmap(NULL, size, prot, MAP_SHARED,
-                    vbasedev->fd,
-                    region->fd_offset + offset);
-        if (*map == MAP_FAILED) {
-            *map = NULL;
-            ret = -errno;
-            goto empty_region;
+        name = g_strdup_printf("%s mmaps[%d]",
+                               memory_region_name(region->mem), i);
+        memory_region_init_ram_ptr(&region->mmaps[i].mem,
+                                   memory_region_owner(region->mem),
+                                   name, region->mmaps[i].size,
+                                   region->mmaps[i].mmap);
+        g_free(name);
+        memory_region_set_skip_dump(&region->mmaps[i].mem);
+        memory_region_add_subregion(region->mem, region->mmaps[i].offset,
+                                    &region->mmaps[i].mem);
+
+        trace_vfio_region_mmap(memory_region_name(&region->mmaps[i].mem),
+                               region->mmaps[i].offset,
+                               region->mmaps[i].offset +
+                               region->mmaps[i].size - 1);
+    }
+
+    return 0;
+}
+
+void vfio_region_exit(VFIORegion *region)
+{
+    int i;
+
+    if (!region->mem) {
+        return;
+    }
+
+    for (i = 0; i < region->nr_mmaps; i++) {
+        if (region->mmaps[i].mmap) {
+            memory_region_del_subregion(region->mem, &region->mmaps[i].mem);
         }
+    }
 
-        memory_region_init_ram_ptr(submem, obj, name, size, *map);
-        memory_region_set_skip_dump(submem);
-    } else {
-empty_region:
-        /* Create a zero sized sub-region to make cleanup easy. */
-        memory_region_init(submem, obj, name, 0);
+    trace_vfio_region_exit(region->vbasedev->name, region->nr);
+}
+
+void vfio_region_finalize(VFIORegion *region)
+{
+    int i;
+
+    if (!region->mem) {
+        return;
     }
 
-    memory_region_add_subregion(mem, offset, submem);
+    for (i = 0; i < region->nr_mmaps; i++) {
+        if (region->mmaps[i].mmap) {
+            munmap(region->mmaps[i].mmap, region->mmaps[i].size);
+            object_unparent(OBJECT(&region->mmaps[i].mem));
+        }
+    }
 
-    return ret;
+    object_unparent(OBJECT(region->mem));
+
+    g_free(region->mem);
+    g_free(region->mmaps);
+
+    trace_vfio_region_finalize(region->vbasedev->name, region->nr);
+}
+
+void vfio_region_mmaps_set_enabled(VFIORegion *region, bool enabled)
+{
+    int i;
+
+    if (!region->mem) {
+        return;
+    }
+
+    for (i = 0; i < region->nr_mmaps; i++) {
+        if (region->mmaps[i].mmap) {
+            memory_region_set_enabled(&region->mmaps[i].mem, enabled);
+        }
+    }
+
+    trace_vfio_region_mmaps_set_enabled(memory_region_name(region->mem),
+                                        enabled);
 }
 
 void vfio_reset_handler(void *opaque)