On 08/26/2015 12:03 AM, Stefan Hajnoczi wrote:
On Fri, Aug 14, 2015 at 10:52:01PM +0800, Xiao Guangrong wrote:
The parameter @file is used as backed memory for NVDIMM which is
divided into two parts if @dataconfig is true:
s/dataconfig/configdata/
Stupid typo, sorry.
@@ -76,13 +109,87 @@ static void pc_nvdimm_init(Object *obj)
set_configdata, NULL);
}
+static uint64_t get_file_size(int fd)
+{
+ struct stat stat_buf;
+ uint64_t size;
+
+ if (fstat(fd, &stat_buf) < 0) {
+ return 0;
+ }
+
+ if (S_ISREG(stat_buf.st_mode)) {
+ return stat_buf.st_size;
+ }
+
+ if (S_ISBLK(stat_buf.st_mode) && !ioctl(fd, BLKGETSIZE64, &size)) {
+ return size;
+ }
#ifdef __linux__ for ioctl(fd, BLKGETSIZE64, &size)?
There is nothing Linux-specific about emulating NVDIMMs so this code
should compile on all platforms.
Right. I have no idea for how block devices work on other platforms so
I will only allow linux to directly use bock device file in the next
version.
+
+ return 0;
+}
+
static void pc_nvdimm_realize(DeviceState *dev, Error **errp)
{
PCNVDIMMDevice *nvdimm = PC_NVDIMM(dev);
+ char name[512];
+ void *buf;
+ ram_addr_t addr;
+ uint64_t size, nvdimm_size, config_size = MIN_CONFIG_DATA_SIZE;
+ int fd;
if (!nvdimm->file) {
error_setg(errp, "file property is not set");
}
Missing return here.
Will fix.
+
+ fd = open(nvdimm->file, O_RDWR);
Does it make sense to support read-only NVDIMMs?
It could be handy for sharing a read-only file between unprivileged
guests. The permissions on the file would only allow read, not write.
Make sense. Currently these patchset just implements "shared" mode so that
write permission is required, however, please see below:
+ if (fd < 0) {
+ error_setg(errp, "can not open %s", nvdimm->file);
s/can not/cannot/
+ return;
+ }
+
+ size = get_file_size(fd);
+ buf = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
I guess the user will want to choose between MAP_SHARED and MAP_PRIVATE.
This can be added in the future.
Good idea, it will allow guest to write data but discards its content after it
exits. Will implement O_RDONLY + MAP_PRIVATE in the near future.
+ if (buf == MAP_FAILED) {
+ error_setg(errp, "can not do mmap on %s", nvdimm->file);
+ goto do_close;
+ }
+
+ nvdimm->config_data_size = config_size;
+ if (nvdimm->configdata) {
+ /* reserve MIN_CONFIGDATA_AREA_SIZE for configue data. */
+ nvdimm_size = size - config_size;
+ nvdimm->config_data_addr = buf + nvdimm_size;
+ } else {
+ nvdimm_size = size;
+ nvdimm->config_data_addr = NULL;
+ }
+
+ if ((int64_t)nvdimm_size <= 0) {
The error cases can be detected before mmap(2). That avoids the int64_t
cast and also avoids nvdimm_size underflow and the bogus
nvdimm->config_data_addr calculation above.
Okay.
size = get_file_size(fd);
if (size == 0) {
error_setg(errp, "empty file or unable to get file size");
goto do_close;
} else if (nvdimm->configdata && size < config_size) {{
error_setg(errp, "file size is too small to store NVDIMM"
" configure data");
goto do_close;
}
+ error_setg(errp, "file size is too small to store NVDIMM"
+ " configure data");
+ goto do_unmap;
+ }
+
+ addr = reserved_range_push(nvdimm_size);
+ if (!addr) {
+ error_setg(errp, "do not have enough space for size %#lx.\n", size);
error_setg() messages must not have a newline at the end.
Please use "%#" PRIx64 instead of "%#lx" so compilation works on 32-bit
hosts where sizeof(long) == 4.
Good catch.
+ goto do_unmap;
+ }
+
+ nvdimm->device_index = new_device_index();
+ sprintf(name, "NVDIMM-%d", nvdimm->device_index);
+ memory_region_init_ram_ptr(&nvdimm->mr, OBJECT(dev), name, nvdimm_size,
+ buf);
How is the autogenerated name used?
Why not just use "pc-nvdimm.memory"?
Ah. Just for debug proposal :) and i am not sure if a name used for multiple
MRs (MemoryRegion) is a good idea.
+ vmstate_register_ram(&nvdimm->mr, DEVICE(dev));
+ memory_region_add_subregion(get_system_memory(), addr, &nvdimm->mr);
+
+ return;
fd is leaked.
Will fix.
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