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

[Peter Krempa]

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.

> +
>      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.