On Mon, Feb 15, 2021 at 04:23:54PM +0100, Greg KH wrote:
On Mon, Feb 15, 2021 at 04:03:21PM +0100, Stefano Garzarella wrote:
On Mon, Feb 15, 2021 at 03:32:19PM +0100, Greg KH wrote:
On Thu, Feb 11, 2021 at 05:25:19PM +0100, Stefano Garzarella wrote:
Commit 65b709586e222fa6ffd4166ac7fdb5d5dad113ee upstream.
No, this really is not that commit, so please do not say it is.
Oops, sorry.
Before this patch, if 'offset + len' was equal to sizeof(struct virtio_net_config), the entire buffer wasn't filled, returning incorrect values to the caller.
Since 'vdpasim->config' type is 'struct virtio_net_config', we can safely copy its content under this condition.
Commit 65b709586e22 ("vdpa_sim: add get_config callback in vdpasim_dev_attr") unintentionally solved it upstream while refactoring vdpa_sim.c to support multiple devices. But we don't want to backport it to stable branches as it contains many changes.
Fixes: 2c53d0f64c06 ("vdpasim: vDPA device simulator") Cc: stable@vger.kernel.org # 5.10.x Signed-off-by: Stefano Garzarella sgarzare@redhat.com
drivers/vdpa/vdpa_sim/vdpa_sim.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c index 6a90fdb9cbfc..8ca178d7b02f 100644 --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c @@ -572,7 +572,7 @@ static void vdpasim_get_config(struct vdpa_device *vdpa, unsigned int offset, { struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
- if (offset + len < sizeof(struct virtio_net_config))
- if (offset + len <= sizeof(struct virtio_net_config)) memcpy(buf, (u8 *)&vdpasim->config + offset, len);
}
I'll be glad to take a one-off patch, but why can't we take the real upstream patch? That is always the better long-term solution, right?
Because that patch depends on the following patches merged in v5.11-rc1 while refactoring vdpa_sim: f37cbbc65178 vdpa_sim: make 'config' generic and usable for any device type cf1a3b35382c vdpa_sim: store parsed MAC address in a buffer a13b5918fdd0 vdpa_sim: add work_fn in vdpasim_dev_attr 011c35bac5ef vdpa_sim: add supported_features field in vdpasim_dev_attr 2f8f46188805 vdpa_sim: add device id field in vdpasim_dev_attr 6c6e28fe4579 vdpa_sim: add struct vdpasim_dev_attr for device attributes 36a9c3063025 vdpa_sim: rename vdpasim_config_ops variables 423248d60d2b vdpa_sim: remove hard-coded virtq count
Maybe we can skip some of them, but IMHO should be less risky to apply only this change.
If you want I can try to figure out the minimum sub-set of patches needed for 65b709586e22 ("vdpa_sim: add get_config callback in vdpasim_dev_attr").
The minimum is always nice :)
The minimum set, including the patch that fixes the issue, is the following:
65b709586e22 vdpa_sim: add get_config callback in vdpasim_dev_attr f37cbbc65178 vdpa_sim: make 'config' generic and usable for any device type cf1a3b35382c vdpa_sim: store parsed MAC address in a buffer 6c6e28fe4579 vdpa_sim: add struct vdpasim_dev_attr for device attributes 423248d60d2b vdpa_sim: remove hard-coded virtq count
The patches apply fairly cleanly. There are a few contextual differences due to the lack of the other patches:
$ git backport-diff -u master -r linux-5.10.y..HEAD Key: [----] : patches are identical [####] : number of functional differences between upstream/downstream patch [down] : patch is downstream-only The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively
001/5:[----] [--] 'vdpa_sim: remove hard-coded virtq count' 002/5:[----] [-C] 'vdpa_sim: add struct vdpasim_dev_attr for device attributes' 003/5:[----] [--] 'vdpa_sim: store parsed MAC address in a buffer' 004/5:[----] [-C] 'vdpa_sim: make 'config' generic and usable for any device type' 005/5:[----] [-C] 'vdpa_sim: add get_config callback in vdpasim_dev_attr'
If it's just too much churn for no good reason, then yes, the one-line change above will be ok, but you need to document the heck out of why this is not upstream and that it is a one-off thing.
Shortly I'll send the series to stable@vger.kernel.org so you can judge if it's okay or better to resend this patch with a better description.
Thanks Stefano