Commit 06329cce authored by Marcel Apfelbaum's avatar Marcel Apfelbaum
Browse files

mem: add share parameter to memory-backend-ram 



Currently only file backed memory backend can
be created with a "share" flag in order to allow
sharing guest RAM with other processes in the host.

Add the "share" flag also to RAM Memory Backend
in order to allow remapping parts of the guest RAM
to different host virtual addresses. This is needed
by the RDMA devices in order to remap non-contiguous
QEMU virtual addresses to a contiguous virtual address range.

Moved the "share" flag to the Host Memory base class,
modified phys_mem_alloc to include the new parameter
and a new interface memory_region_init_ram_shared_nomigrate.

There are no functional changes if the new flag is not used.

Reviewed-by: default avatarEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: default avatarMarcel Apfelbaum <marcel@redhat.com>
parent e5ecc287

backends/hostmem-file.c

+1 −24
Original line number Diff line number Diff line
@@ -31,7 +31,6 @@ typedef struct HostMemoryBackendFile HostMemoryBackendFile; 
struct HostMemoryBackendFile {

    HostMemoryBackend parent_obj;



    bool share;

    bool discard_data;

    char *mem_path;

    uint64_t align;
@@ -59,7 +58,7 @@ file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 
        path = object_get_canonical_path(OBJECT(backend));

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

                                 path,

                                 backend->size, fb->align, fb->share,

                                 backend->size, fb->align, backend->share,

                                 fb->mem_path, errp);

        g_free(path);

    }
@@ -86,25 +85,6 @@ static void set_mem_path(Object *o, const char *str, Error **errp) 
    fb->mem_path = g_strdup(str);

}



static bool file_memory_backend_get_share(Object *o, Error **errp)

{

    HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);



    return fb->share;

}



static void file_memory_backend_set_share(Object *o, bool value, Error **errp)

{

    HostMemoryBackend *backend = MEMORY_BACKEND(o);

    HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);



    if (host_memory_backend_mr_inited(backend)) {

        error_setg(errp, "cannot change property value");

        return;

    }

    fb->share = value;

}



static bool file_memory_backend_get_discard_data(Object *o, Error **errp)

{

    return MEMORY_BACKEND_FILE(o)->discard_data;
@@ -171,9 +151,6 @@ file_backend_class_init(ObjectClass *oc, void *data) 
    bc->alloc = file_backend_memory_alloc;

    oc->unparent = file_backend_unparent;



    object_class_property_add_bool(oc, "share",

        file_memory_backend_get_share, file_memory_backend_set_share,

        &error_abort);

    object_class_property_add_bool(oc, "discard-data",

        file_memory_backend_get_discard_data, file_memory_backend_set_discard_data,

        &error_abort);

backends/hostmem-ram.c

+2 −2
Original line number Diff line number Diff line
@@ -28,8 +28,8 @@ ram_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 
    }



    path = object_get_canonical_path_component(OBJECT(backend));

    memory_region_init_ram_nomigrate(&backend->mr, OBJECT(backend), path,

                           backend->size, errp);

    memory_region_init_ram_shared_nomigrate(&backend->mr, OBJECT(backend), path,

                           backend->size, backend->share, errp);

    g_free(path);

}

backends/hostmem.c

+21 −0
Original line number Diff line number Diff line
@@ -368,6 +368,24 @@ static void set_id(Object *o, const char *str, Error **errp) 
    backend->id = g_strdup(str);

}



static bool host_memory_backend_get_share(Object *o, Error **errp)

{

    HostMemoryBackend *backend = MEMORY_BACKEND(o);



    return backend->share;

}



static void host_memory_backend_set_share(Object *o, bool value, Error **errp)

{

    HostMemoryBackend *backend = MEMORY_BACKEND(o);



    if (host_memory_backend_mr_inited(backend)) {

        error_setg(errp, "cannot change property value");

        return;

    }

    backend->share = value;

}



static void

host_memory_backend_class_init(ObjectClass *oc, void *data)

{
@@ -398,6 +416,9 @@ host_memory_backend_class_init(ObjectClass *oc, void *data) 
        host_memory_backend_get_policy,

        host_memory_backend_set_policy, &error_abort);

    object_class_property_add_str(oc, "id", get_id, set_id, &error_abort);

    object_class_property_add_bool(oc, "share",

        host_memory_backend_get_share, host_memory_backend_set_share,

        &error_abort);

}



static void host_memory_backend_finalize(Object *o)

exec.c

+15 −11
Original line number Diff line number Diff line
@@ -1285,7 +1285,7 @@ static int subpage_register (subpage_t *mmio, uint32_t start, uint32_t end, 
                             uint16_t section);

static subpage_t *subpage_init(FlatView *fv, hwaddr base);



static void *(*phys_mem_alloc)(size_t size, uint64_t *align) =

static void *(*phys_mem_alloc)(size_t size, uint64_t *align, bool shared) =

                               qemu_anon_ram_alloc;



/*
@@ -1293,7 +1293,7 @@ static void *(*phys_mem_alloc)(size_t size, uint64_t *align) = 
 * Accelerators with unusual needs may need this.  Hopefully, we can

 * get rid of it eventually.

 */

void phys_mem_set_alloc(void *(*alloc)(size_t, uint64_t *align))

void phys_mem_set_alloc(void *(*alloc)(size_t, uint64_t *align, bool shared))

{

    phys_mem_alloc = alloc;

}
@@ -1921,7 +1921,7 @@ static void dirty_memory_extend(ram_addr_t old_ram_size, 
    }

}



static void ram_block_add(RAMBlock *new_block, Error **errp)

static void ram_block_add(RAMBlock *new_block, Error **errp, bool shared)

{

    RAMBlock *block;

    RAMBlock *last_block = NULL;
@@ -1944,7 +1944,7 @@ static void ram_block_add(RAMBlock *new_block, Error **errp) 
            }

        } else {

            new_block->host = phys_mem_alloc(new_block->max_length,

                                             &new_block->mr->align);

                                             &new_block->mr->align, shared);

            if (!new_block->host) {

                error_setg_errno(errp, errno,

                                 "cannot set up guest memory '%s'",
@@ -2049,7 +2049,7 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr, 
        return NULL;

    }



    ram_block_add(new_block, &local_err);

    ram_block_add(new_block, &local_err, share);

    if (local_err) {

        g_free(new_block);

        error_propagate(errp, local_err);
@@ -2091,7 +2091,7 @@ RAMBlock *qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size, 
                                  void (*resized)(const char*,

                                                  uint64_t length,

                                                  void *host),

                                  void *host, bool resizeable,

                                  void *host, bool resizeable, bool share,

                                  MemoryRegion *mr, Error **errp)

{

    RAMBlock *new_block;
@@ -2114,7 +2114,7 @@ RAMBlock *qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size, 
    if (resizeable) {

        new_block->flags |= RAM_RESIZEABLE;

    }

    ram_block_add(new_block, &local_err);

    ram_block_add(new_block, &local_err, share);

    if (local_err) {

        g_free(new_block);

        error_propagate(errp, local_err);
@@ -2126,12 +2126,15 @@ RAMBlock *qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size, 
RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,

                                   MemoryRegion *mr, Error **errp)

{

    return qemu_ram_alloc_internal(size, size, NULL, host, false, mr, errp);

    return qemu_ram_alloc_internal(size, size, NULL, host, false,

                                   false, mr, errp);

}



RAMBlock *qemu_ram_alloc(ram_addr_t size, MemoryRegion *mr, Error **errp)

RAMBlock *qemu_ram_alloc(ram_addr_t size, bool share,

                         MemoryRegion *mr, Error **errp)

{

    return qemu_ram_alloc_internal(size, size, NULL, NULL, false, mr, errp);

    return qemu_ram_alloc_internal(size, size, NULL, NULL, false,

                                   share, mr, errp);

}



RAMBlock *qemu_ram_alloc_resizeable(ram_addr_t size, ram_addr_t maxsz,
@@ -2140,7 +2143,8 @@ RAMBlock *qemu_ram_alloc_resizeable(ram_addr_t size, ram_addr_t maxsz, 
                                                     void *host),

                                     MemoryRegion *mr, Error **errp)

{

    return qemu_ram_alloc_internal(size, maxsz, resized, NULL, true, mr, errp);

    return qemu_ram_alloc_internal(size, maxsz, resized, NULL, true,

                                   false, mr, errp);

}



static void reclaim_ramblock(RAMBlock *block)

include/exec/memory.h

+23 −0
Original line number Diff line number Diff line
@@ -435,6 +435,29 @@ void memory_region_init_ram_nomigrate(MemoryRegion *mr, 
                                      uint64_t size,

                                      Error **errp);



/**

 * memory_region_init_ram_shared_nomigrate:  Initialize RAM memory region.

 *                                           Accesses into the region will

 *                                           modify memory directly.

 *

 * @mr: the #MemoryRegion to be initialized.

 * @owner: the object that tracks the region's reference count

 * @name: Region name, becomes part of RAMBlock name used in migration stream

 *        must be unique within any device

 * @size: size of the region.

 * @share: allow remapping RAM to different addresses

 * @errp: pointer to Error*, to store an error if it happens.

 *

 * Note that this function is similar to memory_region_init_ram_nomigrate.

 * The only difference is part of the RAM region can be remapped.

 */

void memory_region_init_ram_shared_nomigrate(MemoryRegion *mr,

                                             struct Object *owner,

                                             const char *name,

                                             uint64_t size,

                                             bool share,

                                             Error **errp);



/**

 * memory_region_init_resizeable_ram:  Initialize memory region with resizeable

 *                                     RAM.  Accesses into the region will