Re: [PATCH] vhost-vdpa: cleanup memory maps when closing vdpa fds

[Longpeng (Mike, Cloud Infrastructure Service Product Dept.)]

在 2023/2/14 14:16, Jason Wang 写道:
> 在 2023/1/31 22:53, Longpeng(Mike) 写道:
> > From: Longpeng <longpeng2@xxxxxxxxxx>
> >
> > We must cleanup all memory maps when closing the vdpa fds, otherwise
> > some critical resources (e.g. memory, iommu map) will leaked if the
> > userspace exits unexpectedly (e.g. kill -9).
>
>
> Sounds like a bug of the kernel, should we fix there?

For example, the iommu map is setup when QEMU calls VHOST_IOTLB_UPDATE 
ioctl and it'll be freed if QEMU calls VHOST_IOTLB_INVALIDATE ioctl.

So maybe we release these resources in vdpa framework in kernel is a 
suitable choice?

By the way, Jason, can you reproduce the problem in your machine?

> Thanks
>
>
> > Signed-off-by: Longpeng <longpeng2@xxxxxxxxxx>
> > ---
> >   drivers/vhost/vdpa.c | 13 +++++++++++++
> >   1 file changed, 13 insertions(+)
> >
> > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> > index a527eeeac637..37477cffa5aa 100644
> > --- a/drivers/vhost/vdpa.c
> > +++ b/drivers/vhost/vdpa.c
> > @@ -823,6 +823,18 @@ static void vhost_vdpa_unmap(struct vhost_vdpa *v,
> >           vhost_vdpa_remove_as(v, asid);
> >   }
> > +static void vhost_vdpa_clean_map(struct vhost_vdpa *v)
> > +{
> > +    struct vhost_vdpa_as *as;
> > +    u32 asid;
> > +
> > +    for (asid = 0; asid < v->vdpa->nas; asid++) {
> > +        as = asid_to_as(v, asid);
> > +        if (as)
> > +            vhost_vdpa_unmap(v, &as->iotlb, 0ULL, 0ULL - 1);
> > +    }
> > +}
> > +
> >   static int vhost_vdpa_va_map(struct vhost_vdpa *v,
> >                    struct vhost_iotlb *iotlb,
> >                    u64 iova, u64 size, u64 uaddr, u32 perm)
> > @@ -1247,6 +1259,7 @@ static int vhost_vdpa_release(struct inode 
> > *inode, struct file *filep)
> >       vhost_vdpa_clean_irq(v);
> >       vhost_vdpa_reset(v);
> >       vhost_dev_stop(&v->vdev);
> > +    vhost_vdpa_clean_map(v);
> >       vhost_vdpa_free_domain(v);
> >       vhost_vdpa_config_put(v);
> >       vhost_vdpa_cleanup(v);
>
> .