[PATCH 4/7] qemu: Support update disk's bootindex

[Jiang Jiacheng]

On 2022/11/22 23:17, Peter Krempa wrote:
> On Thu, Nov 17, 2022 at 10:05:30 +0800, Jiang Jiacheng wrote:
>> Support to update the disk's bootindex using 'virsh update-device'.
>> Using flag --config or --persistent to change the boot index and the
>> change will be affected after reboot. With --persistent, we can get
>> the result of change immediently, but it still takes effect after reboot.
>> Currently, support update bootindex of disk type as cdrom or disk.
>>
>> Signed-off-by: Jiang Jiacheng <jiangjiacheng at huawei.com>
>> ---
>>  src/qemu/qemu_domain.c |  3 ++-
>>  src/qemu/qemu_driver.c | 28 ++++++++++++++++++++++++++++
>>  2 files changed, 30 insertions(+), 1 deletion(-)
> 
> [...]
> 
>> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
>> index ff5a743716..65abc04998 100644
>> --- a/src/qemu/qemu_driver.c
>> +++ b/src/qemu/qemu_driver.c
>> @@ -6767,6 +6767,7 @@ qemuDomainChangeDiskLive(virDomainObj *vm,
>>      virDomainDiskDef *orig_disk = NULL;
>>      virDomainStartupPolicy origStartupPolicy;
>>      virDomainDeviceDef oldDev = { .type = dev->type };
>> +    int needChangeIndex = 0;
>>  
>>      if (!(orig_disk = virDomainDiskByTarget(vm->def, disk->dst))) {
>>          virReportError(VIR_ERR_INTERNAL_ERROR,
>> @@ -6784,6 +6785,10 @@ qemuDomainChangeDiskLive(virDomainObj *vm,
>>      if (!qemuDomainDiskChangeSupported(disk, orig_disk))
>>          return -1;
>>  
>> +    if ((needChangeIndex = qemuCheckBootIndex(&orig_disk->info,
>> +                                              disk->info.bootIndex)) < 0)
>> +        return -1;
> 
> Due to the weird check I complained about in previous patch, this
> actively breaks media change (and other parameter change) for disks
> which don't have bootindex.
>
This check do have this problem , I should fix it. I only want to return
-1 when add a bootindex for a device whose bootindex is not set before.

>> +
>>      if (!virStorageSourceIsSameLocation(disk->src, orig_disk->src)) {
>>          /* Disk source can be changed only for removable devices */
>>          if (disk->device != VIR_DOMAIN_DISK_DEVICE_CDROM &&
>> @@ -6807,6 +6812,11 @@ qemuDomainChangeDiskLive(virDomainObj *vm,
>>          dev->data.disk->src = NULL;
>>      }
>>  
>> +    if (needChangeIndex) {
>> +        if (qemuChangeDiskBootIndex(vm, orig_disk, disk) < 0)
>> +            return -1;
>> +    }
>> +
>>      /* in case when we aren't updating disk source we update startup policy here */
>>      orig_disk->startupPolicy = dev->data.disk->startupPolicy;
>>      orig_disk->snapshot = dev->data.disk->snapshot;
>> @@ -7503,6 +7513,24 @@ qemuDomainUpdateDeviceConfig(virDomainDef *vmdef,
>>                                           false) < 0)
>>              return -1;
>>  
>> +        switch (vmdef->disks[pos]->device) {
>> +        case VIR_DOMAIN_DISK_DEVICE_CDROM:
>> +        case VIR_DOMAIN_DISK_DEVICE_DISK:
>> +        case VIR_DOMAIN_DISK_DEVICE_LUN:
>> +            if (qemuCheckBootIndex(&vmdef->disks[pos]->info,
>> +                                   newDisk->info.bootIndex) < 0)
>> +                return -1;
>> +             break;
>> +        case VIR_DOMAIN_DISK_DEVICE_FLOPPY:
>> +        case VIR_DOMAIN_DISK_DEVICE_LAST:
>> +            if ((newDisk->info.bootIndex) &&
>> +                (vmdef->disks[pos]->info.bootIndex != newDisk->info.bootIndex)) {
>> +                virReportError(VIR_ERR_INVALID_ARG, "%s",
>> +                               _("this disk doesn't support update"));
>> +                return -1;
>> +            }
>> +        }
> 
> This also doesn't make sense. You don't have the same issue updating the
> bootindex of a floppy. Similarly, the qemuCheckBootIndex check is also
> not applicable as the next boot config willr esult in a new boot where
> you can change anything.
> 
My patches don't support change floppy's bootindex, so it will return an
error if the bootindex is changed in its xml.