On Mon, Jul 8, 2024 at 3:06 PM Cindy Lu <lulu@xxxxxxxxxx> wrote: > > On Fri, 5 Jul 2024 at 20:42, Stefano Garzarella <sgarzare@xxxxxxxxxx> wrote: > > > > On Fri, Jul 05, 2024 at 07:30:51AM GMT, Michael S. Tsirkin wrote: > > >On Fri, Jul 05, 2024 at 01:28:21PM +0200, Stefano Garzarella wrote: > > >> The vDPA block simulator always allocated a 128 MiB ram-disk, but some > > >> filesystems (e.g. XFS) may require larger minimum sizes (see > > >> https://issues.redhat.com/browse/RHEL-45951). > > >> > > >> So to allow us to test these filesystems, let's add a module parameter > > >> to control the size of the simulated virtio-blk devices. > > >> The value is mapped directly to the `capacity` field of the virtio-blk > > >> configuration space, so it must be expressed in sector numbers of 512 > > >> bytes. > > >> > > >> The default value (0x40000) is the same as the previous value, so the > > >> behavior without setting `capacity` remains unchanged. > > >> > > >> Before this patch or with this patch without setting `capacity`: > > >> $ modprobe vdpa-sim-blk > > >> $ vdpa dev add mgmtdev vdpasim_blk name blk0 > > >> virtio_blk virtio6: 1/0/0 default/read/poll queues > > >> virtio_blk virtio6: [vdb] 262144 512-byte logical blocks (134 MB/128 MiB) > > >> > > >> After this patch: > > >> $ modprobe vdpa-sim-blk capacity=614400 > > >> $ vdpa dev add mgmtdev vdpasim_blk name blk0 > > >> virtio_blk virtio6: 1/0/0 default/read/poll queues > > >> virtio_blk virtio6: [vdb] 614400 512-byte logical blocks (315 MB/300 MiB) > > >> > > >> Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx> > > > > > >What a hack. Cindy was working on adding control over config > > >space, why can't that be used? > > > > If it can be used easily with virtio-blk device too, it will be great. > > @Cindy do you plan to support that changes for a virtio-blk device too? > > > Hi Stefano > I plan to add support to change the vdpa device's configuration after > it is created. I think for Stefano's case, we can just implement it via provisioning parameters? Thanks > In the first step, I want to use the vdpa tool to add > support for changing the MAC address for the network device. the next > step will also add MTU settings etc > here is the link > https://lore.kernel.org/all/20240708064820.88955-1-lulu@xxxxxxxxxx/T/#t > > in the device part, the device needs to implement its function of > int (*dev_set_attr)(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev, > const struct vdpa_dev_set_config *config); > the configuration will be passed by struct vdpa_dev_set_config. I'm > not sure if this kind of design is suitable for you? Really thanks and > any comments are welcome > thanks > Cindy > > > > In the mean time, for the simulator I thought that this change was fine. > > It's just used for testing and debugging... > > > > My main question is how to use that when we have `shared_backend` set to > > true, since we use that setting to test for example live migration. In > > that case, how do we handle the size of the shared ramdisk between > > devices? > > > > Thanks, > > Stefano > > >
