Hi All,
We tested xm block-configure command.
Because when the domain image is made, we install it from multiple CDROM.
The procedure of the installation is as follows.
1) The HVM domain is started with the CDROM device.
・configuration file :
disk = [
'file:/xen/test/install-test.img,hda,w','phy:/dev/cdrom,hdc:cdrom,r' ]
boot="d"
2) When the installation from CDROM of the first piece is completed, CDROM is
exchanged.
3) The exchange of CD-ROM is set by the xm block-configure command.
# xm block-configure <DomID> phy:/dev/cdrom hdc:cdrom r
4) The installation from CDROM of the second piece is continued.
However, there are two problems in this procedure.
1) It takes time to recognize the exchange of CDROM.
2) Even if the same device is specified, it is not recognized.
We investigated these problems.
1) It takes time to recognize the exchange of CDROM.
The problem that it takes time for recognition is to wait intentionally on the
qemu-dm side.
・tools/ioemu/xenstore.c
314 void xenstore_process_event(void *opaque)
315 {
...
343 if (image[0]) {
344 media_filename[hd_index] = strdup(image);
345 xenstore_check_new_media_present(5000); << This
346 }
The processing recognized after it waits for five seconds is executed.
We think that this waiting is unnecessary after exchanges CDROM.
Why do you wait for five seconds before CDROM recognizes it?
If it is unnecessary, we want to correct not to wait.
2) Even if the same device is specified, it is not recognized.
Therefore, we allocated it in other devices once.
# xm block-configure <DomID> phy:/dev/null hdc:cdrom r
# xm block-configure <DomID> phy:/dev/cdrom hdc:cdrom r
It is made not to recognize that the same device is specified in qemu-dm.
・tools/ioemu/xenstore.c
314 void xenstore_process_event(void *opaque)
315 {
...
332 image = xs_read(xsh, XBT_NULL, vec[XS_WATCH_PATH], &len);
333 if (image == NULL || !strcmp(image, bs_table[hd_index]->filename)) <<
This
334 goto out; /* gone or identical */
It doesn't operate because it becomes naturally the same name
when physics CDROM is allocated.
Even if the name is the same, the content might be not same.
Only when CDROM is exchanged, it is executed.
When the same device is specified, should we check it?
We want to correct not to check it.
We have confirmed these problems are canceled by the appended patch.
Best Regards,
--
Takanori Kasai
cd_change_ioemu.patch
Description: Binary data
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