Hi Matthew,
On 10/4/23 01:08, Matthew Rosato wrote:
> On 10/3/23 11:25 AM, Cédric Le Goater wrote:
>> On 10/3/23 12:14, Eric Auger wrote:
>>> Let the vfio-ap device use vfio_attach_device() and
>>> vfio_detach_device(), hence hiding the details of the used
>>> IOMMU backend.
>>>
>>> We take the opportunity to use g_path_get_basename() which
>>> is prefered, as suggested by
>>> 3e015d815b ("use g_path_get_basename instead of basename")
>>>
>>> Signed-off-by: Eric Auger <eric.au...@redhat.com>
>>> Signed-off-by: Yi Liu <yi.l....@intel.com>
>>> Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com>
>>>
>>> ---
>>>
>>> v2 -> v3:
>>> - Mention g_path_get_basename in commit message and properly free
>>> vbasedev->name, call vfio_detach_device
>>> ---
>>> hw/vfio/ap.c | 70 ++++++++++------------------------------------------
>>> 1 file changed, 13 insertions(+), 57 deletions(-)
>>>
>>> diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
>>> index 6e21d1da5a..d0b587b3b1 100644
>>> --- a/hw/vfio/ap.c
>>> +++ b/hw/vfio/ap.c
>>> @@ -53,40 +53,6 @@ struct VFIODeviceOps vfio_ap_ops = {
>>> .vfio_compute_needs_reset = vfio_ap_compute_needs_reset,
>>> };
>>> -static void vfio_ap_put_device(VFIOAPDevice *vapdev)
>>> -{
>>> - g_free(vapdev->vdev.name);
>>> - vfio_put_base_device(&vapdev->vdev);
>>> -}
>>> -
>>> -static VFIOGroup *vfio_ap_get_group(VFIOAPDevice *vapdev, Error **errp)
>>> -{
>>> - GError *gerror = NULL;
>>> - char *symlink, *group_path;
>>> - int groupid;
>>> -
>>> - symlink = g_strdup_printf("%s/iommu_group", vapdev->vdev.sysfsdev);
>>> - group_path = g_file_read_link(symlink, &gerror);
>>> - g_free(symlink);
>>> -
>>> - if (!group_path) {
>>> - error_setg(errp, "%s: no iommu_group found for %s: %s",
>>> - TYPE_VFIO_AP_DEVICE, vapdev->vdev.sysfsdev,
>>> gerror->message);
>>> - g_error_free(gerror);
>>> - return NULL;
>>> - }
>>> -
>>> - if (sscanf(basename(group_path), "%d", &groupid) != 1) {
>>> - error_setg(errp, "vfio: failed to read %s", group_path);
>>> - g_free(group_path);
>>> - return NULL;
>>> - }
>>> -
>>> - g_free(group_path);
>>> -
>>> - return vfio_get_group(groupid, &address_space_memory, errp);
>>> -}
>>> -
>>> static void vfio_ap_req_notifier_handler(void *opaque)
>>> {
>>> VFIOAPDevice *vapdev = opaque;
>>> @@ -189,22 +155,15 @@ static void
>>> vfio_ap_unregister_irq_notifier(VFIOAPDevice *vapdev,
>>> static void vfio_ap_realize(DeviceState *dev, Error **errp)
>>> {
>>> int ret;
>>> - char *mdevid;
>>> Error *err = NULL;
>>> - VFIOGroup *vfio_group;
>>> APDevice *apdev = AP_DEVICE(dev);
>>> VFIOAPDevice *vapdev = VFIO_AP_DEVICE(apdev);
>>> + VFIODevice *vbasedev = &vapdev->vdev;
>>> - vfio_group = vfio_ap_get_group(vapdev, errp);
>>> - if (!vfio_group) {
>>> - return;
>>> - }
>>> -
>>> - vapdev->vdev.ops = &vfio_ap_ops;
>>> - vapdev->vdev.type = VFIO_DEVICE_TYPE_AP;
>>> - mdevid = basename(vapdev->vdev.sysfsdev);
>>> - vapdev->vdev.name = g_strdup_printf("%s", mdevid);
>>> - vapdev->vdev.dev = dev;
>>> + vbasedev->name = g_path_get_basename(vbasedev->sysfsdev);
>>> + vbasedev->ops = &vfio_ap_ops;
>>> + vbasedev->type = VFIO_DEVICE_TYPE_AP;
>>> + vbasedev->dev = dev;
>>> /*
>>> * vfio-ap devices operate in a way compatible with discarding of
>>> @@ -214,9 +173,11 @@ static void vfio_ap_realize(DeviceState *dev, Error
>>> **errp)
>>> */
>>> vapdev->vdev.ram_block_discard_allowed = true;
>>> - ret = vfio_get_device(vfio_group, mdevid, &vapdev->vdev, errp);
>>> + ret = vfio_attach_device(vbasedev->name, vbasedev,
>>> + &address_space_memory, errp);
>>> if (ret) {
>>> - goto out_get_dev_err;
>>> + g_free(vbasedev->name);
>>> + return;
>>> }
>>> vfio_ap_register_irq_notifier(vapdev, VFIO_AP_REQ_IRQ_INDEX, &err);
>>> @@ -225,25 +186,20 @@ static void vfio_ap_realize(DeviceState *dev, Error
>>> **errp)
>>> * Report this error, but do not make it a failing condition.
>>> * Lack of this IRQ in the host does not prevent normal operation.
>>> */
>>> + vfio_detach_device(vbasedev);
>>> error_report_err(err);
>>> + g_free(vbasedev->name);
> This patch overall looks good to me and passes basic tests with vfio-ap
> devices. But I note that this addition of detach+free here runs counter to
> what the comment block above it states and prior behavior (where we did not
> goto out_get_dev_err for this case and expect the realize to complete
> successfully despite this error).
>
> In this error case, we only report the local 'err' contents and nothing is
> propagated into 'errp' -- which means that to the caller dc->realize() should
> be viewed as successful (errp is NULL) and so we should be able to assume a
> subsequent dc->unrealize() will do this g_free+detach later.
yes you totally right. Just need to do the error_report_err(err); in
that case.
Thanks!
Eric
>
>>> }
>>> -
>>> - return;
>>> -
>>> -out_get_dev_err:
>>> - vfio_ap_put_device(vapdev);
>>> - vfio_put_group(vfio_group);
>>> }
>>
>> To be consistent with vfio_(pci)_realize(), I would introduce the same
>> failure path at the end the routine :
>>
>> out_detach:
>> vfio_detach_device(vbasedev);
>> error:
>> error_prepend(errp, VFIO_MSG_PREFIX, vbasedev->name);
>> g_free(vbasedev->name);
> So based on my comment above, I think you'd only need the 'error:' case now,
> but otherwise adding this error_prepend seems reasonable to me too.
>
> Thanks,
> Matt
>
>>
>> and add the VFIO_MSG_PREFIX while we are at it.
>>
>> This is minor, so :
>>
>> Reviewed-by: Cédric Le Goater <c...@redhat.com>
>>
>> Thanks,
>>
>> C.
>>
>>
>>
>>> static void vfio_ap_unrealize(DeviceState *dev)
>>> {
>>> APDevice *apdev = AP_DEVICE(dev);
>>> VFIOAPDevice *vapdev = VFIO_AP_DEVICE(apdev);
>>> - VFIOGroup *group = vapdev->vdev.group;
>>> vfio_ap_unregister_irq_notifier(vapdev, VFIO_AP_REQ_IRQ_INDEX);
>>> - vfio_ap_put_device(vapdev);
>>> - vfio_put_group(group);
>>> + vfio_detach_device(&vapdev->vdev);
>>> + g_free(vapdev->vdev.name);
>>> }
>>> static Property vfio_ap_properties[] = {
