Commit faf8a13d authored by Junyan He's avatar Junyan He Committed by Michael S. Tsirkin
Browse files

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: default avatarHaozhong Zhang <haozhong.zhang@intel.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarIgor Mammedov <imammedo@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarRichard Henderson <richard.henderson@linaro.org>
parent a4de8552

hw/mem/nvdimm.c

+8 −1
Original line number Diff line number Diff line
@@ -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);



    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;

include/qemu/pmem.h

0 → 100644
+30 −0
Original line number Diff line number Diff line 
/*

 * 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 */