Emulated devices and other BlockBackend users wishing to take advantage
of blk_register_buf() all have the same repetitive job: register
RAMBlocks with the BlockBackend using RAMBlockNotifier.
Add a BlockRAMRegistrar API to do this. A later commit will use this
from hw/block/virtio-blk.c.
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
MAINTAINERS | 1 +
include/sysemu/block-ram-registrar.h | 30 +++++++++++++++++++++
block/block-ram-registrar.c | 39 ++++++++++++++++++++++++++++
block/meson.build | 1 +
4 files changed, 71 insertions(+)
create mode 100644 include/sysemu/block-ram-registrar.h
create mode 100644 block/block-ram-registrar.c
diff --git a/MAINTAINERS b/MAINTAINERS
index d839301f68..655f79c9f7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2462,6 +2462,7 @@ F: block*
F: block/
F: hw/block/
F: include/block/
+F: include/sysemu/block-*.h
F: qemu-img*
F: docs/tools/qemu-img.rst
F: qemu-io*
diff --git a/include/sysemu/block-ram-registrar.h
b/include/sysemu/block-ram-registrar.h
new file mode 100644
index 0000000000..09d63f64b2
--- /dev/null
+++ b/include/sysemu/block-ram-registrar.h
@@ -0,0 +1,30 @@
+/*
+ * BlockBackend RAM Registrar
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef BLOCK_RAM_REGISTRAR_H
+#define BLOCK_RAM_REGISTRAR_H
+
+#include "exec/ramlist.h"
+
+/**
+ * struct BlockRAMRegistrar:
+ *
+ * Keeps RAMBlock memory registered with a BlockBackend using
+ * blk_register_buf() including hotplugged memory.
+ *
+ * Emulated devices or other BlockBackend users initialize a BlockRAMRegistrar
+ * with blk_ram_registrar_init() before submitting I/O requests with the
+ * BLK_REQ_REGISTERED_BUF flag set.
+ */
+typedef struct {
+ BlockBackend *blk;
+ RAMBlockNotifier notifier;
+} BlockRAMRegistrar;
+
+void blk_ram_registrar_init(BlockRAMRegistrar *r, BlockBackend *blk);
+void blk_ram_registrar_destroy(BlockRAMRegistrar *r);
+
+#endif /* BLOCK_RAM_REGISTRAR_H */
diff --git a/block/block-ram-registrar.c b/block/block-ram-registrar.c
new file mode 100644
index 0000000000..32a14b69ae
--- /dev/null
+++ b/block/block-ram-registrar.c
@@ -0,0 +1,39 @@
+/*
+ * BlockBackend RAM Registrar
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "sysemu/block-backend.h"
+#include "sysemu/block-ram-registrar.h"
+
+static void ram_block_added(RAMBlockNotifier *n, void *host, size_t size,
+ size_t max_size)
+{
+ BlockRAMRegistrar *r = container_of(n, BlockRAMRegistrar, notifier);
+ blk_register_buf(r->blk, host, max_size);
+}
+
+static void ram_block_removed(RAMBlockNotifier *n, void *host, size_t size,
+ size_t max_size)
+{
+ BlockRAMRegistrar *r = container_of(n, BlockRAMRegistrar, notifier);
+ blk_unregister_buf(r->blk, host, max_size);
+}
+
+void blk_ram_registrar_init(BlockRAMRegistrar *r, BlockBackend *blk)
+{
+ r->blk = blk;
+ r->notifier = (RAMBlockNotifier){
+ .ram_block_added = ram_block_added,
+ .ram_block_removed = ram_block_removed,
+ };
+
+ ram_block_notifier_add(&r->notifier);
+}
+
+void blk_ram_registrar_destroy(BlockRAMRegistrar *r)
+{
+ ram_block_notifier_remove(&r->notifier);
+}
diff --git a/block/meson.build b/block/meson.build
index 787667384a..b315593054 100644
--- a/block/meson.build
+++ b/block/meson.build
@@ -46,6 +46,7 @@ block_ss.add(files(
), zstd, zlib, gnutls)
softmmu_ss.add(when: 'CONFIG_TCG', if_true: files('blkreplay.c'))
+softmmu_ss.add(files('block-ram-registrar.c'))
if get_option('qcow1').allowed()
block_ss.add(files('qcow.c'))
--
2.35.1
