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Re: [Qemu-devel] [PATCH v6 07/13] vfio/ccw: vfio based subchannel passth
From: |
Dong Jia Shi |
Subject: |
Re: [Qemu-devel] [PATCH v6 07/13] vfio/ccw: vfio based subchannel passthrough driver |
Date: |
Tue, 2 May 2017 13:07:53 +0800 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
* Auger Eric <address@hidden> [2017-05-01 13:08:05 +0200]:
Hi Eric,
[...]
> > diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
> > new file mode 100644
> > index 0000000..cd4dfe8
> > --- /dev/null
> > +++ b/hw/vfio/ccw.c
[...]
> > +static VFIOGroup *vfio_ccw_get_group(S390CCWDevice *cdev, Error **errp)
> > +{
> > + char *tmp, group_path[PATH_MAX];
> > + ssize_t len;
> > + int groupid;
> > +
> > + tmp = g_strdup_printf("/sys/bus/css/devices/%x.%x.%04x/%s/iommu_group",
> > + cdev->hostid.cssid, cdev->hostid.ssid,
> > + cdev->hostid.devid, cdev->mdevid);
> May be worth replacing this static function by a common
> vfio_get_device_group(VFIODevice *vbasedev, Error **errp) in common.c
> that would be used by vfio/pci devices? It would use the sysfsdev
> populated before.
Are you propsing that we introduce a common interface for all of the
devices which use the quite alike logic of populating the sysfsdev?
I put this on my todo list, and prefer to defer it to a time after this
set upstreamed.
> > + len = readlink(tmp, group_path, sizeof(group_path));
> > + g_free(tmp);
> > +
> > + if (len <= 0 || len >= sizeof(group_path)) {
> > + error_setg(errp, "vfio: no iommu_group found");
> may be good to align the error message with pci/platform. I noticed the
> case where len==0 is handled as ENAMETOOLONG on pci/platform which looks
> bad. Maybe this is why you changed it.
I copy this from pci.c. :>
And I agree with you that, the error message is better to be aligned if
it's possible to do that.
> > + return NULL;
> > + }
> > +
> > + group_path[len] = 0;
> > +
> > + if (sscanf(basename(group_path), "%d", &groupid) != 1) {
> > + error_setg(errp, "vfio: failed to read %s", group_path);
> > + return NULL;
> > + }
> > +
> > + return vfio_get_group(groupid, &address_space_memory, errp);
> > +}
> > +
> > +static void vfio_ccw_put_group(VFIOGroup *group)
> Is it really needed?
Ok. Removed.
> > +{
> > + vfio_put_group(group);
> > +}
> > +
> > +static void vfio_ccw_realize(DeviceState *dev, Error **errp)
> > +{
> > + VFIODevice *vbasedev;
> > + VFIOGroup *group;
> > + CcwDevice *ccw_dev = DO_UPCAST(CcwDevice, parent_obj, dev);
> > + S390CCWDevice *cdev = DO_UPCAST(S390CCWDevice, parent_obj, ccw_dev);
> > + VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev);
> > + S390CCWDeviceClass *cdc = S390_CCW_DEVICE_GET_CLASS(cdev);
> > +
> > + /* Call the class init function for subchannel. */
> > + if (cdc->realize) {
> > + cdc->realize(cdev, vcdev->vdev.sysfsdev, errp);
> > + if (*errp) {
> use local err?
Ok.
>
> Thanks
>
> Eric
> > + return;
> > + }
> > + }
> > +
> > + group = vfio_ccw_get_group(cdev, errp);
> > + if (!group) {
> > + goto out_group_err;
> > + }
> > +
> > + vcdev->vdev.ops = &vfio_ccw_ops;
> > + vcdev->vdev.type = VFIO_DEVICE_TYPE_CCW;
> > + vcdev->vdev.name = g_strdup_printf("%x.%x.%04x", cdev->hostid.cssid,
> > + cdev->hostid.ssid,
> > cdev->hostid.devid);
> > + QLIST_FOREACH(vbasedev, &group->device_list, next) {
> > + if (strcmp(vbasedev->name, vcdev->vdev.name) == 0) {
> > + error_setg(errp, "vfio: subchannel %s has already been
> > attached",
> > + vcdev->vdev.name);
> > + goto out_device_err;
> > + }
> > + }
> > +
> > + if (vfio_get_device(group, cdev->mdevid, &vcdev->vdev, errp)) {
> > + goto out_device_err;
> > + }
> > +
> > + return;
> > +
> > +out_device_err:
> > + vfio_ccw_put_group(group);
> > +out_group_err:
> > + if (cdc->unrealize) {
> > + cdc->unrealize(cdev, errp);
> > + }
> > +}
> > +
[...]
--
Dong Jia Shi