Re: [libvirt] [PATCH v5] qemu: call drive_del in DetachPciDiskDevice

Currently libvirt doesn't confirm whether the guest has responded to the disk removal request. In some cases this can leave the guest with continued access to the device while the mgmt layer believes that it has been removed. With a recent qemu monitor command[1] we can deterministically revoke a guests access to the disk (on the QEMU side) to ensure no futher access is permitted.

This patch adds support for the drive_del() command and introduces it in the disk removal paths. If the guest is running in a QEMU without this command we currently explicitly check for unknown command/CommandNotFound and log the issue. If QEMU supports the command we issue the drive_del command after we attempt to remove the device. The guest may respond and remove the block device before we get to attempt to call drive_del. In that case, we explicitly check for 'Device not found' from the monitor indicating that the target drive was auto-deleted upon guest responds to the device removal notification. 1. http://thread.gmane.org/gmane.comp.emulators.qemu/84745

src/qemu/qemu_driver.c | 28 +++++++++++++++++++++ src/qemu/qemu_monitor.c | 19 ++++++++++++++ src/qemu/qemu_monitor.h | 3 ++ src/qemu/qemu_monitor_json.c | 38 +++++++++++++++++++++++++++++ src/qemu/qemu_monitor_json.h | 3 ++ src/qemu/qemu_monitor_text.c | 54 ++++++++++++++++++++++++++++++++++++++++++ src/qemu/qemu_monitor_text.h | 3 ++ 7 files changed, 148 insertions(+), 0 deletions(-)