[libvirt] About 'virsh update-device' for floppy and cdrom

Hi experts: When I did some test, I was puzzled by one thing: When I use "virsh update-device" to update floppy device, always got an error message, "error: internal error unable to execute QEMU command 'change': Could not open'***file':Permission denied".But when I execute command "setenforce 0" befroe "udpate-device", floppy device can be updated. Steps like this: ---------------------------------------------------------------Start # virsh start virt-tests-vm1 Domain virt-tests-vm1 started # cat /add_storage/liyang/github-autotest_new/client/tests/virt/tmp/tmp/update_iso.xml <disk type='file' device='floppy'> <driver name='qemu' type='raw'/> <source file='/add_storage/liyang/github-autotest_new/client/tests/virt/tmp/tmp/change_media_old.iso'/> <target dev='fda'/> <readonly/> </disk> # ll /add_storage/liyang/github-autotest_new/client/tests/virt/tmp/tmp/change_media_old.iso -rw-r--r--. 1 qemu qemu 1404928 Sep 20 10:48 /add_storage/liyang/github-autotest_new/client/tests/virt/tmp/tmp/change_media_old.iso # virsh update-device virt-tests-vm1 /add_storage/liyang/github-autotest_new/client/tests/virt/tmp/tmp/update_iso.xml --force error: Failed to update device from /add_storage/liyang/github-autotest_new/client/tests/virt/tmp/tmp/update_iso.xml error: internal error unable to execute QEMU command 'change': Could not open '/add_storage/liyang/github-autotest_new/client/tests/virt/tmp/tmp/change_media_old.iso': Permission denied # cat /selinux/enforce 1 # setenforce 0 # virsh update-device virt-tests-vm1 /add_storage/liyang/github-autotest_new/client/tests/virt/tmp/tmp/update_iso.xml --force Device updated successfully ---------------------------------------------------------------End But with same command, about cdrom device it worked though "/selinux/enforce" is 1. Steps like this: ---------------------------------------------------------------Start # virsh start virt-tests-vm1 Domain virt-tests-vm1 started # cat /add_storage/liyang/github-autotest_new/client/tests/virt/tmp/tmp/update_iso.xml <disk type='file' device='cdrom'> <driver name='qemu' type='raw'/> <source file='/add_storage/liyang/github-autotest_new/client/tests/virt/tmp/tmp/change_media_old.iso'/> <target dev='hdc'/> <readonly/> </disk> # ll /add_storage/liyang/github-autotest_new/client/tests/virt/tmp/tmp/change_media_old.iso -rw-r--r--. 1 qemu qemu 1404928 Sep 20 10:58 /add_storage/liyang/github-autotest_new/client/tests/virt/tmp/tmp/change_media_old.iso # cat /selinux/enforce 1 # virsh update-device virt-tests-vm1 /add_storage/liyang/github-autotest_new/client/tests/virt/tmp/tmp/update_iso.xml --force Device updated successfully ---------------------------------------------------------------End So I want to know why it's different between 'floppy' and 'cdrom', and what's the difference? Also why floppy needs 'permissive' mode but cdrom doesn't? Wish your help! -- Regards, -------------------------------------------------- Li Yang TEL：+86+25-86630566-8529 EMail：liyang.fnst(a)cn.fujitsu.com --------------------------------------------------