Re: [PATCH 1/3] vfio: Make VFIOIOMMUClass::attach_device() and its wrapper return bool

["Cédric Le Goater" <clg@redhat.com>]

On 5/7/24 04:09, Duan, Zhenzhong wrote:
> 
> 
>> -----Original Message-----
>> From: Cédric Le Goater <clg@redhat.com>
>> Subject: Re: [PATCH 1/3] vfio: Make VFIOIOMMUClass::attach_device() and
>> its wrapper return bool
>>
>> On 5/6/24 10:33, Zhenzhong Duan wrote:
>>> Make VFIOIOMMUClass::attach_device() and its wrapper function
>>> vfio_attach_device() return bool.
>>>
>>> This is to follow the coding standand to return bool if 'Error **'
>>> is used to pass error.
>>>
>>> Suggested-by: Cédric Le Goater <clg@redhat.com>
>>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>>> ---
>>>    include/hw/vfio/vfio-common.h         |  4 ++--
>>>    include/hw/vfio/vfio-container-base.h |  4 ++--
>>>    hw/vfio/ap.c                          |  6 ++----
>>>    hw/vfio/ccw.c                         |  6 ++----
>>>    hw/vfio/common.c                      |  4 ++--
>>>    hw/vfio/container.c                   | 14 +++++++-------
>>>    hw/vfio/iommufd.c                     | 11 +++++------
>>>    hw/vfio/pci.c                         |  8 +++-----
>>>    hw/vfio/platform.c                    |  7 +++----
>>>    9 files changed, 28 insertions(+), 36 deletions(-)
>>>
>>> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-
>> common.h
>>> index b9da6c08ef..a7b6fc8f46 100644
>>> --- a/include/hw/vfio/vfio-common.h
>>> +++ b/include/hw/vfio/vfio-common.h
>>> @@ -198,8 +198,8 @@ void vfio_region_exit(VFIORegion *region);
>>>    void vfio_region_finalize(VFIORegion *region);
>>>    void vfio_reset_handler(void *opaque);
>>>    struct vfio_device_info *vfio_get_device_info(int fd);
>>> -int vfio_attach_device(char *name, VFIODevice *vbasedev,
>>> -                       AddressSpace *as, Error **errp);
>>> +bool vfio_attach_device(char *name, VFIODevice *vbasedev,
>>> +                        AddressSpace *as, Error **errp);
>>>    void vfio_detach_device(VFIODevice *vbasedev);
>>>
>>>    int vfio_kvm_device_add_fd(int fd, Error **errp);
>>> diff --git a/include/hw/vfio/vfio-container-base.h b/include/hw/vfio/vfio-
>> container-base.h
>>> index 3582d5f97a..c839cfd9cb 100644
>>> --- a/include/hw/vfio/vfio-container-base.h
>>> +++ b/include/hw/vfio/vfio-container-base.h
>>> @@ -118,8 +118,8 @@ struct VFIOIOMMUClass {
>>>        int (*dma_unmap)(const VFIOContainerBase *bcontainer,
>>>                         hwaddr iova, ram_addr_t size,
>>>                         IOMMUTLBEntry *iotlb);
>>> -    int (*attach_device)(const char *name, VFIODevice *vbasedev,
>>> -                         AddressSpace *as, Error **errp);
>>> +    bool (*attach_device)(const char *name, VFIODevice *vbasedev,
>>> +                          AddressSpace *as, Error **errp);
>>>        void (*detach_device)(VFIODevice *vbasedev);
>>>        /* migration feature */
>>>        int (*set_dirty_page_tracking)(const VFIOContainerBase *bcontainer,
>>> diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
>>> index 7c4caa5938..d50600b702 100644
>>> --- a/hw/vfio/ap.c
>>> +++ b/hw/vfio/ap.c
>>> @@ -156,7 +156,6 @@ static void
>> vfio_ap_unregister_irq_notifier(VFIOAPDevice *vapdev,
>>>    static void vfio_ap_realize(DeviceState *dev, Error **errp)
>>>    {
>>>        ERRP_GUARD();
>>> -    int ret;
>>>        Error *err = NULL;
>>>        VFIOAPDevice *vapdev = VFIO_AP_DEVICE(dev);
>>>        VFIODevice *vbasedev = &vapdev->vdev;
>>> @@ -165,9 +164,8 @@ static void vfio_ap_realize(DeviceState *dev, Error
>> **errp)
>>>            return;
>>>        }
>>>
>>> -    ret = vfio_attach_device(vbasedev->name, vbasedev,
>>> -                             &address_space_memory, errp);
>>> -    if (ret) {
>>> +    if (!vfio_attach_device(vbasedev->name, vbasedev,
>>> +                            &address_space_memory, errp)) {
>>>            goto error;
>>>        }
>>>
>>> diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
>>> index 90e4a53437..782bd4bed7 100644
>>> --- a/hw/vfio/ccw.c
>>> +++ b/hw/vfio/ccw.c
>>> @@ -580,7 +580,6 @@ static void vfio_ccw_realize(DeviceState *dev,
>> Error **errp)
>>>        S390CCWDeviceClass *cdc = S390_CCW_DEVICE_GET_CLASS(cdev);
>>>        VFIODevice *vbasedev = &vcdev->vdev;
>>>        Error *err = NULL;
>>> -    int ret;
>>>
>>>        /* Call the class init function for subchannel. */
>>>        if (cdc->realize) {
>>> @@ -594,9 +593,8 @@ static void vfio_ccw_realize(DeviceState *dev,
>> Error **errp)
>>>            return;
>>>        }
>>>
>>> -    ret = vfio_attach_device(cdev->mdevid, vbasedev,
>>> -                             &address_space_memory, errp);
>>> -    if (ret) {
>>> +    if (!vfio_attach_device(cdev->mdevid, vbasedev,
>>> +                            &address_space_memory, errp)) {
>>>            goto out_attach_dev_err;
>>>        }
>>>
>>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
>>> index 8f9cbdc026..890d30910e 100644
>>> --- a/hw/vfio/common.c
>>> +++ b/hw/vfio/common.c
>>> @@ -1492,8 +1492,8 @@ retry:
>>>        return info;
>>>    }
>>>
>>> -int vfio_attach_device(char *name, VFIODevice *vbasedev,
>>> -                       AddressSpace *as, Error **errp)
>>> +bool vfio_attach_device(char *name, VFIODevice *vbasedev,
>>> +                        AddressSpace *as, Error **errp)
>>>    {
>>>        const VFIOIOMMUClass *ops =
>>>
>> VFIO_IOMMU_CLASS(object_class_by_name(TYPE_VFIO_IOMMU_LEGACY));
>>
>>
>> I think vfio_attach_device() can be cleaned up a little further :
>>
>>     ret = ops->attach_device(name, vbasedev, as, errp);
>>      if (ret < 0) {
>>          return ret;
>>      }
> 
> Not understand this.
> I have both ops->attach_device() and vfio_attach_device() return bool
> in this patch. Do you mean drop the change for ops->attach_device()?
> Or split the two changes?

The return value of ops->attach_device() should be tested as a bool now
and not as an int, as it is still currently done.

See the fix here :
      https://gitlab.com/legoater/qemu/-/commit/abae88dc28e723745fe2ff506ea9f0adeb47afdb

Please simply fold the changes in this patch.

Thanks,

C.


>>
>>
>>> diff --git a/hw/vfio/container.c b/hw/vfio/container.c
>>> index 77bdec276e..ea3b145913 100644
>>> --- a/hw/vfio/container.c
>>> +++ b/hw/vfio/container.c
>>> @@ -908,8 +908,8 @@ static int vfio_device_groupid(VFIODevice
>> *vbasedev, Error **errp)
>>>     * @name and @vbasedev->name are likely to be different depending
>>>     * on the type of the device, hence the need for passing @name
>>>     */
>>> -static int vfio_legacy_attach_device(const char *name, VFIODevice
>> *vbasedev,
>>> -                                     AddressSpace *as, Error **errp)
>>> +static bool vfio_legacy_attach_device(const char *name, VFIODevice
>> *vbasedev,
>>> +                                      AddressSpace *as, Error **errp)
>>>    {
>>>        int groupid = vfio_device_groupid(vbasedev, errp);
>>>        VFIODevice *vbasedev_iter;
>>> @@ -918,27 +918,27 @@ static int vfio_legacy_attach_device(const char
>> *name, VFIODevice *vbasedev,
>>>        int ret;
>>>
>>>        if (groupid < 0) {
>>> -        return groupid;
>>> +        return false;
>>>        }
>>>
>>>        trace_vfio_attach_device(vbasedev->name, groupid);
>>>
>>>        group = vfio_get_group(groupid, as, errp);
>>>        if (!group) {
>>> -        return -ENOENT;
>>> +        return false;
>>>        }
>>>
>>>        QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
>>>            if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
>>>                error_setg(errp, "device is already attached");
>>>                vfio_put_group(group);
>>> -            return -EBUSY;
>>> +            return false;
>>>            }
>>>        }
>>>        ret = vfio_get_device(group, name, vbasedev, errp);
>>>        if (ret) {
>>
>> vfio_get_device() would be the next candidate for cleanup.
> 
> Yes.
> 
>>
>>>            vfio_put_group(group);
>>> -        return ret;
>>> +        return false;
>>>        }
>>>
>>>        bcontainer = &group->container->bcontainer;
>>> @@ -946,7 +946,7 @@ static int vfio_legacy_attach_device(const char
>> *name, VFIODevice *vbasedev,
>>>        QLIST_INSERT_HEAD(&bcontainer->device_list, vbasedev,
>> container_next);
>>>        QLIST_INSERT_HEAD(&vfio_device_list, vbasedev, global_next);
>>>
>>> -    return ret;
>>> +    return true;
>>>    }
>>>
>>>    static void vfio_legacy_detach_device(VFIODevice *vbasedev)
>>> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
>>> index 8827ffe636..9aa0dd6d8e 100644
>>> --- a/hw/vfio/iommufd.c
>>> +++ b/hw/vfio/iommufd.c
>>> @@ -301,8 +301,8 @@ error:
>>>        return ret;
>>>    }
>>>
>>> -static int iommufd_cdev_attach(const char *name, VFIODevice *vbasedev,
>>> -                               AddressSpace *as, Error **errp)
>>> +static bool iommufd_cdev_attach(const char *name, VFIODevice
>> *vbasedev,
>>> +                                AddressSpace *as, Error **errp)
>>>    {
>>>        VFIOContainerBase *bcontainer;
>>>        VFIOIOMMUFDContainer *container;
>>> @@ -317,7 +317,7 @@ static int iommufd_cdev_attach(const char *name,
>> VFIODevice *vbasedev,
>>>        if (vbasedev->fd < 0) {
>>>            devfd = iommufd_cdev_getfd(vbasedev->sysfsdev, errp);
>>>            if (devfd < 0) {
>>> -            return devfd;
>>> +            return false;
>>>            }
>>>            vbasedev->fd = devfd;
>>>        } else {
>>> @@ -394,7 +394,6 @@ static int iommufd_cdev_attach(const char *name,
>> VFIODevice *vbasedev,
>>>        memory_listener_register(&bcontainer->listener, bcontainer->space-
>>> as);
>>>
>>>        if (bcontainer->error) {
>>> -        ret = -1;
>>>            error_propagate_prepend(errp, bcontainer->error,
>>>                                    "memory listener initialization failed: ");
>>>            goto err_listener_register;
>>> @@ -433,7 +432,7 @@ found_container:
>>>
>>>        trace_iommufd_cdev_device_info(vbasedev->name, devfd, vbasedev-
>>> num_irqs,
>>>                                       vbasedev->num_regions, vbasedev->flags);
>>> -    return 0;
>>> +    return true;
>>>
>>>    err_listener_register:
>>>        iommufd_cdev_ram_block_discard_disable(false);
>>> @@ -446,7 +445,7 @@ err_alloc_ioas:
>>>        iommufd_cdev_unbind_and_disconnect(vbasedev);
>>>    err_connect_bind:
>>>        close(vbasedev->fd);
>>> -    return ret;
>>> +    return false;
>>>    }
>>>
>>>    static void iommufd_cdev_detach(VFIODevice *vbasedev)
>>> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
>>> index 64780d1b79..952e4b1a25 100644
>>> --- a/hw/vfio/pci.c
>>> +++ b/hw/vfio/pci.c
>>> @@ -2951,7 +2951,7 @@ static void vfio_realize(PCIDevice *pdev, Error
>> **errp)
>>>        int i, ret;
>>>        bool is_mdev;
>>>        char uuid[UUID_STR_LEN];
>>> -    char *name;
>>> +    g_autofree char *name = NULL;
>>>
>>>        if (vbasedev->fd < 0 && !vbasedev->sysfsdev) {
>>>            if (!(~vdev->host.domain || ~vdev->host.bus ||
>>> @@ -3001,10 +3001,8 @@ static void vfio_realize(PCIDevice *pdev, Error
>> **errp)
>>>            name = g_strdup(vbasedev->name);
>>>        }
>>>
>>> -    ret = vfio_attach_device(name, vbasedev,
>>> -                             pci_device_iommu_address_space(pdev), errp);
>>> -    g_free(name);
>>
>> This change would deserve another patch.
> 
> Will do.
> 
> Thanks
> Zhenzhong