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loader: Handle memory-mapped ELFs

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This patch allows handling an ELF memory-mapped, taking care
the reference count of the GMappedFile* passed through
rom_add_elf_program().
In this case, the 'data' pointer is not heap-allocated, so
we cannot free it.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20190724143105.307042-2-sgarzare@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Stefano Garzarella 2019-07-24 16:31:03 +02:00 committed by Paolo Bonzini
parent b896c4b50d
commit fef28891aa
3 changed files with 34 additions and 11 deletions
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38
hw/core/loader.c
View File

@ -838,6 +838,7 @@ struct Rom {
int isrom;
char *fw_dir;
char *fw_file;
GMappedFile *mapped_file;
bool committed;
@ -848,10 +849,25 @@ struct Rom {
static FWCfgState *fw_cfg;
static QTAILQ_HEAD(, Rom) roms = QTAILQ_HEAD_INITIALIZER(roms);
/* rom->data must be heap-allocated (do not use with rom_add_elf_program()) */
/*
* rom->data can be heap-allocated or memory-mapped (e.g. when added with
* rom_add_elf_program())
*/
static void rom_free_data(Rom *rom)
{
if (rom->mapped_file) {
g_mapped_file_unref(rom->mapped_file);
rom->mapped_file = NULL;
} else {
g_free(rom->data);
}
rom->data = NULL;
}
static void rom_free(Rom *rom)
{
g_free(rom->data);
rom_free_data(rom);
g_free(rom->path);
g_free(rom->name);
g_free(rom->fw_dir);
@ -1058,11 +1074,12 @@ MemoryRegion *rom_add_blob(const char *name, const void *blob, size_t len,
/* This function is specific for elf program because we don't need to allocate
* all the rom. We just allocate the first part and the rest is just zeros. This
* is why romsize and datasize are different. Also, this function seize the
* memory ownership of "data", so we don't have to allocate and copy the buffer.
* is why romsize and datasize are different. Also, this function takes its own
* reference to "mapped_file", so we don't have to allocate and copy the buffer.
*/
int rom_add_elf_program(const char *name, void *data, size_t datasize,
size_t romsize, hwaddr addr, AddressSpace *as)
int rom_add_elf_program(const char *name, GMappedFile *mapped_file, void *data,
size_t datasize, size_t romsize, hwaddr addr,
AddressSpace *as)
{
Rom *rom;
@ -1073,6 +1090,12 @@ int rom_add_elf_program(const char *name, void *data, size_t datasize,
rom->romsize = romsize;
rom->data = data;
rom->as = as;
if (mapped_file && data) {
g_mapped_file_ref(mapped_file);
rom->mapped_file = mapped_file;
}
rom_insert(rom);
return 0;
}
@ -1107,8 +1130,7 @@ static void rom_reset(void *unused)
}
if (rom->isrom) {
/* rom needs to be written only once */
g_free(rom->data);
rom->data = NULL;
rom_free_data(rom);
}
/*
* The rom loader is really on the same level as firmware in the guest

2
include/hw/elf_ops.h
View File

@ -525,7 +525,7 @@ static int glue(load_elf, SZ)(const char *name, int fd,
snprintf(label, sizeof(label), "phdr #%d: %s", i, name);
/* rom_add_elf_program() seize the ownership of 'data' */
rom_add_elf_program(label, data, file_size, mem_size,
rom_add_elf_program(label, NULL, data, file_size, mem_size,
addr, as);
} else {
address_space_write(as ? as : &address_space_memory,

5
include/hw/loader.h
View File

@ -258,8 +258,9 @@ MemoryRegion *rom_add_blob(const char *name, const void *blob, size_t len,
FWCfgCallback fw_callback,
void *callback_opaque, AddressSpace *as,
bool read_only);
int rom_add_elf_program(const char *name, void *data, size_t datasize,
size_t romsize, hwaddr addr, AddressSpace *as);
int rom_add_elf_program(const char *name, GMappedFile *mapped_file, void *data,
size_t datasize, size_t romsize, hwaddr addr,
AddressSpace *as);
int rom_check_and_register_reset(void);
void rom_set_fw(FWCfgState *f);
void rom_set_order_override(int order);