[PATCH v4 01/13] util: vfio-helpers: Factor out and fix processing of existing ram blocks

[David Hildenbrand]

Factor it out into common code when a new notifier is registered, just
as done with the memory region notifier. This allows us to have the
logic about how to process existing ram blocks at a central place (which
will be extended soon).

Just like when adding a new ram block, we have to register the max_length
for now. We don't have a way to get notified about resizes yet, and some
memory would not be mapped when growing the ram block.

Note: Currently, ram blocks are only "fake resized". All memory
(max_length) is accessible.

We can get rid of a bunch of functions in stubs/ram-block.c . Print the
warning from inside qemu_vfio_ram_block_added().

Reviewed-by: Peter Xu <address@hidden>
Cc: Richard Henderson <address@hidden>
Cc: Paolo Bonzini <address@hidden>
Cc: Eduardo Habkost <address@hidden>
Cc: Marcel Apfelbaum <address@hidden>
Cc: Alex Williamson <address@hidden>
Cc: Stefan Hajnoczi <address@hidden>
Cc: Peter Xu <address@hidden>
Signed-off-by: David Hildenbrand <address@hidden>
---
 exec.c                    |  5 +++++
 hw/core/numa.c            | 14 ++++++++++++++
 include/exec/cpu-common.h |  1 +
 util/vfio-helpers.c       | 29 ++++++++---------------------
 4 files changed, 28 insertions(+), 21 deletions(-)

diff --git a/exec.c b/exec.c
index 2874bb5088..4f804347a6 100644
--- a/exec.c
+++ b/exec.c
@@ -1966,6 +1966,11 @@ ram_addr_t qemu_ram_get_used_length(RAMBlock *rb)
     return rb->used_length;
 }
 
+ram_addr_t qemu_ram_get_max_length(RAMBlock *rb)
+{
+    return rb->max_length;
+}
+
 bool qemu_ram_is_shared(RAMBlock *rb)
 {
     return rb->flags & RAM_SHARED;
diff --git a/hw/core/numa.c b/hw/core/numa.c
index 316bc50d75..dc5e5b4046 100644
--- a/hw/core/numa.c
+++ b/hw/core/numa.c
@@ -854,9 +854,23 @@ void query_numa_node_mem(NumaNodeMem node_mem[], 
MachineState *ms)
     }
 }
 
+static int ram_block_notify_add_single(RAMBlock *rb, void *opaque)
+{
+    const ram_addr_t max_size = qemu_ram_get_max_length(rb);
+    void *host = qemu_ram_get_host_addr(rb);
+    RAMBlockNotifier *notifier = opaque;
+
+    if (host) {
+        notifier->ram_block_added(notifier, host, max_size);
+    }
+    return 0;
+}
+
 void ram_block_notifier_add(RAMBlockNotifier *n)
 {
     QLIST_INSERT_HEAD(&ram_list.ramblock_notifiers, n, next);
+    /* Notify about all existing ram blocks. */
+    qemu_ram_foreach_block(ram_block_notify_add_single, n);
 }
 
 void ram_block_notifier_remove(RAMBlockNotifier *n)
diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index b47e5630e7..09decb8d93 100644
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -59,6 +59,7 @@ const char *qemu_ram_get_idstr(RAMBlock *rb);
 void *qemu_ram_get_host_addr(RAMBlock *rb);
 ram_addr_t qemu_ram_get_offset(RAMBlock *rb);
 ram_addr_t qemu_ram_get_used_length(RAMBlock *rb);
+ram_addr_t qemu_ram_get_max_length(RAMBlock *rb);
 bool qemu_ram_is_shared(RAMBlock *rb);
 bool qemu_ram_is_uf_zeroable(RAMBlock *rb);
 void qemu_ram_set_uf_zeroable(RAMBlock *rb);
diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c
index ddd9a96e76..260570ae19 100644
--- a/util/vfio-helpers.c
+++ b/util/vfio-helpers.c
@@ -376,8 +376,14 @@ static void qemu_vfio_ram_block_added(RAMBlockNotifier *n,
                                       void *host, size_t size)
 {
     QEMUVFIOState *s = container_of(n, QEMUVFIOState, ram_notifier);
+    int ret;
+
     trace_qemu_vfio_ram_block_added(s, host, size);
-    qemu_vfio_dma_map(s, host, size, false, NULL);
+    ret = qemu_vfio_dma_map(s, host, size, false, NULL);
+    if (ret) {
+        error_report("qemu_vfio_dma_map(%p, %zu) failed: %s", host, size,
+                     strerror(-ret));
+    }
 }
 
 static void qemu_vfio_ram_block_removed(RAMBlockNotifier *n,
@@ -390,33 +396,14 @@ static void qemu_vfio_ram_block_removed(RAMBlockNotifier 
*n,
     }
 }
 
-static int qemu_vfio_init_ramblock(RAMBlock *rb, void *opaque)
-{
-    void *host_addr = qemu_ram_get_host_addr(rb);
-    ram_addr_t length = qemu_ram_get_used_length(rb);
-    int ret;
-    QEMUVFIOState *s = opaque;
-
-    if (!host_addr) {
-        return 0;
-    }
-    ret = qemu_vfio_dma_map(s, host_addr, length, false, NULL);
-    if (ret) {
-        fprintf(stderr, "qemu_vfio_init_ramblock: failed %p %" PRId64 "\n",
-                host_addr, (uint64_t)length);
-    }
-    return 0;
-}
-
 static void qemu_vfio_open_common(QEMUVFIOState *s)
 {
     qemu_mutex_init(&s->lock);
     s->ram_notifier.ram_block_added = qemu_vfio_ram_block_added;
     s->ram_notifier.ram_block_removed = qemu_vfio_ram_block_removed;
-    ram_block_notifier_add(&s->ram_notifier);
     s->low_water_mark = QEMU_VFIO_IOVA_MIN;
     s->high_water_mark = QEMU_VFIO_IOVA_MAX;
-    qemu_ram_foreach_block(qemu_vfio_init_ramblock, s);
+    ram_block_notifier_add(&s->ram_notifier);
 }
 
 /**
-- 
2.25.1