From faf8a13d80de98b43342a7ec9878b4fd76b18327 Mon Sep 17 00:00:00 2001
From: Junyan He <junyan.he@intel.com>
Date: Wed, 18 Jul 2018 15:48:01 +0800
Subject: [PATCH] mem/nvdimm: ensure write persistence to PMEM in label
emulation
Guest writes to vNVDIMM labels are intercepted and performed on the
backend by QEMU. When the backend is a real persistent memort, QEMU
needs to take proper operations to ensure its write persistence on the
persistent memory. Otherwise, a host power failure may result in the
loss of guest label configurations.
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
hw/mem/nvdimm.c | 9 ++++++++-
include/qemu/pmem.h | 30 ++++++++++++++++++++++++++++++
2 files changed, 38 insertions(+), 1 deletion(-)
create mode 100644 include/qemu/pmem.h
diff --git a/hw/mem/nvdimm.c b/hw/mem/nvdimm.c
index 021d1c3997..1c6674c4ed 100644
--- a/hw/mem/nvdimm.c
+++ b/hw/mem/nvdimm.c
@@ -23,6 +23,7 @@
*/
#include "qemu/osdep.h"
+#include "qemu/pmem.h"
#include "qapi/error.h"
#include "qapi/visitor.h"
#include "hw/mem/nvdimm.h"
@@ -164,11 +165,17 @@ static void nvdimm_write_label_data(NVDIMMDevice *nvdimm, const void *buf,
{
MemoryRegion *mr;
PCDIMMDevice *dimm = PC_DIMM(nvdimm);
+ bool is_pmem = object_property_get_bool(OBJECT(dimm->hostmem),
+ "pmem", NULL);
uint64_t backend_offset;
nvdimm_validate_rw_label_data(nvdimm, size, offset);
- memcpy(nvdimm->label_data + offset, buf, size);
+ if (!is_pmem) {
+ memcpy(nvdimm->label_data + offset, buf, size);
+ } else {
+ pmem_memcpy_persist(nvdimm->label_data + offset, buf, size);
+ }
mr = host_memory_backend_get_memory(dimm->hostmem);
backend_offset = memory_region_size(mr) - nvdimm->label_size + offset;
diff --git a/include/qemu/pmem.h b/include/qemu/pmem.h
new file mode 100644
index 0000000000..ebdb070210
--- /dev/null
+++ b/include/qemu/pmem.h
@@ -0,0 +1,30 @@
+/*
+ * QEMU header file for libpmem.
+ *
+ * Copyright (c) 2018 Intel Corporation.
+ *
+ * Author: Haozhong Zhang <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef QEMU_PMEM_H
+#define QEMU_PMEM_H
+
+#ifdef CONFIG_LIBPMEM
+#include <libpmem.h>
+#else /* !CONFIG_LIBPMEM */
+
+static inline void *
+pmem_memcpy_persist(void *pmemdest, const void *src, size_t len)
+{
+ /* If 'pmem' option is 'on', we should always have libpmem support,
+ or qemu will report a error and exit, never come here. */
+ g_assert_not_reached();
+ return NULL;
+}
+
+#endif /* CONFIG_LIBPMEM */
+
+#endif /* !QEMU_PMEM_H */
--
2.30.2