[libvirt] [RFC v1 3/6] qemu: add check ephemeral devices only for PCI host devices

[Chen Fan]

On 05/13/2015 04:17 PM, Peter Krempa wrote:
> On Wed, May 13, 2015 at 11:36:29 +0800, Chen Fan wrote:
>> currently, we only support PCI host devices with ephemeral flag.
>> and USB already supports migration. so maybe in the near future we
>> can support SCSI.
>>
>> Signed-off-by: Chen Fan <chen.fan.fnst at cn.fujitsu.com>
>> ---
>>   src/qemu/qemu_command.c   | 10 ++++++++++
>>   src/qemu/qemu_migration.c | 11 +++++++----
>>   2 files changed, 17 insertions(+), 4 deletions(-)
>>
>> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
>> index fc81214..5acd8b4 100644
>> --- a/src/qemu/qemu_command.c
>> +++ b/src/qemu/qemu_command.c
>> @@ -10182,6 +10182,16 @@ qemuBuildCommandLine(virConnectPtr conn,
>>   
>>           /* PCI */
>>           if (hostdev->mode == VIR_DOMAIN_HOSTDEV_MODE_SUBSYS &&
>> +            hostdev->source.subsys.type != VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_USB &&
>> +            (hostdev->source.subsys.type != VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_PCI &&
>> +             hostdev->ephemeral)) {
>> +            virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
>> +                           _("non-USB and non-PCI device assignment with ephemeral "
>> +                             "flag are not supported by this version of qemu"));
> This functionality is not based on qemu support but on libvirt
> implementation so the error message is incorrect.
indeed.

thanks for pointing out this.

Chen
>> +            goto error;
>> +        }
>> +
>> +        if (hostdev->mode == VIR_DOMAIN_HOSTDEV_MODE_SUBSYS &&
>>               hostdev->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_PCI) {
>>               int backend = hostdev->source.subsys.u.pci.backend;
>>   
>> diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
>> index 83be435..56112f9 100644
>> --- a/src/qemu/qemu_migration.c
>> +++ b/src/qemu/qemu_migration.c
>> @@ -1981,21 +1981,24 @@ qemuMigrationIsAllowed(virQEMUDriverPtr driver, virDomainObjPtr vm,
>>           def = vm->def;
>>       }
>>   
>> -    /* Migration with USB host devices is allowed, all other devices are
>> -     * forbidden.
>> +    /*
>> +     * Migration with USB and ephemeral PCI host devices host devices are allowed,
>> +     * all other devices are forbidden.
>>        */
>>       forbid = false;
>>       for (i = 0; i < def->nhostdevs; i++) {
>>           virDomainHostdevDefPtr hostdev = def->hostdevs[i];
>>           if (hostdev->mode != VIR_DOMAIN_HOSTDEV_MODE_SUBSYS ||
>> -            hostdev->source.subsys.type != VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_USB) {
>> +            (hostdev->source.subsys.type != VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_USB &&
>> +            !hostdev->ephemeral)) {
>>               forbid = true;
>>               break;
>>           }
>>       }
>>       if (forbid) {
>>           virReportError(VIR_ERR_OPERATION_INVALID, "%s",
>> -                       _("domain has assigned non-USB host devices"));
>> +                       _("domain has assigned non-USB and "
>> +                         "non-ephemeral host devices"));
>>           return false;
>>       }
> This patch has to be moved after you actually implement the ephemeral
> device unplug code, since an intermediate state would allow to bypass
> the check while the devices actually would not be unplugged.
>
> Peter