Commit a35ba7be authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Michael S. Tsirkin
Browse files

hostmem: allow preallocation of any memory region 



And allow preallocation of file-based memory even without -mem-prealloc.
Some care is necessary because -mem-prealloc does not allow disabling
preallocation for hostmem-file.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarHu Tao <hutao@cn.fujitsu.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 605d0a94

backends/hostmem-file.c

+3 −0
Original line number Diff line number Diff line
@@ -9,7 +9,9 @@ 
 * This work is licensed under the terms of the GNU GPL, version 2 or later.

 * See the COPYING file in the top-level directory.

 */

#include "qemu-common.h"

#include "sysemu/hostmem.h"

#include "sysemu/sysemu.h"

#include "qom/object_interfaces.h"



/* hostmem-file.c */
@@ -46,6 +48,7 @@ file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 
    error_setg(errp, "-mem-path not supported on this host");

#else

    if (!memory_region_size(&backend->mr)) {

        backend->force_prealloc = mem_prealloc;

        memory_region_init_ram_from_file(&backend->mr, OBJECT(backend),

                                 object_get_canonical_path(OBJECT(backend)),

                                 backend->size,

backends/hostmem.c

+42 −0
Original line number Diff line number Diff line
@@ -105,6 +105,41 @@ static void host_memory_backend_set_dump(Object *obj, bool value, Error **errp) 
    }

}



static bool host_memory_backend_get_prealloc(Object *obj, Error **errp)

{

    HostMemoryBackend *backend = MEMORY_BACKEND(obj);



    return backend->prealloc || backend->force_prealloc;

}



static void host_memory_backend_set_prealloc(Object *obj, bool value,

                                             Error **errp)

{

    HostMemoryBackend *backend = MEMORY_BACKEND(obj);



    if (backend->force_prealloc) {

        if (value) {

            error_setg(errp,

                       "remove -mem-prealloc to use the prealloc property");

            return;

        }

    }



    if (!memory_region_size(&backend->mr)) {

        backend->prealloc = value;

        return;

    }



    if (value && !backend->prealloc) {

        int fd = memory_region_get_fd(&backend->mr);

        void *ptr = memory_region_get_ram_ptr(&backend->mr);

        uint64_t sz = memory_region_size(&backend->mr);



        os_mem_prealloc(fd, ptr, sz);

        backend->prealloc = true;

    }

}



static void host_memory_backend_init(Object *obj)

{

    HostMemoryBackend *backend = MEMORY_BACKEND(obj);
@@ -113,6 +148,7 @@ static void host_memory_backend_init(Object *obj) 
                                       "mem-merge", true);

    backend->dump = qemu_opt_get_bool(qemu_get_machine_opts(),

                                      "dump-guest-core", true);

    backend->prealloc = mem_prealloc;



    object_property_add_bool(obj, "merge",

                        host_memory_backend_get_merge,
@@ -120,6 +156,9 @@ static void host_memory_backend_init(Object *obj) 
    object_property_add_bool(obj, "dump",

                        host_memory_backend_get_dump,

                        host_memory_backend_set_dump, NULL);

    object_property_add_bool(obj, "prealloc",

                        host_memory_backend_get_prealloc,

                        host_memory_backend_set_prealloc, NULL);

    object_property_add(obj, "size", "int",

                        host_memory_backend_get_size,

                        host_memory_backend_set_size, NULL, NULL, NULL);
@@ -165,6 +204,9 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp) 
        if (!backend->dump) {

            qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);

        }

        if (backend->prealloc) {

            os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz);

        }

    }

}

exec.c

+7 −0
Original line number Diff line number Diff line
@@ -1448,6 +1448,13 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length) 
}

#endif /* !_WIN32 */



int qemu_get_ram_fd(ram_addr_t addr)

{

    RAMBlock *block = qemu_get_ram_block(addr);



    return block->fd;

}



/* Return a host pointer to ram allocated with qemu_ram_alloc.

   With the exception of the softmmu code in this file, this should

   only be used for local memory (e.g. video ram) that the device owns,

include/exec/memory.h

+10 −0
Original line number Diff line number Diff line
@@ -533,6 +533,16 @@ bool memory_region_is_logging(MemoryRegion *mr); 
 */

bool memory_region_is_rom(MemoryRegion *mr);



/**

 * memory_region_get_fd: Get a file descriptor backing a RAM memory region.

 *

 * Returns a file descriptor backing a file-based RAM memory region,

 * or -1 if the region is not a file-based RAM memory region.

 *

 * @mr: the RAM or alias memory region being queried.

 */

int memory_region_get_fd(MemoryRegion *mr);



/**

 * memory_region_get_ram_ptr: Get a pointer into a RAM memory region.

 *

include/exec/ram_addr.h

+1 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ ram_addr_t qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr, 
ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,

                                   MemoryRegion *mr);

ram_addr_t qemu_ram_alloc(ram_addr_t size, MemoryRegion *mr);

int qemu_get_ram_fd(ram_addr_t addr);

void *qemu_get_ram_ptr(ram_addr_t addr);

void qemu_ram_free(ram_addr_t addr);

void qemu_ram_free_from_ptr(ram_addr_t addr);