Re: [PATCH] vhost-vdpa: honor CAP_IPC_LOCK

[Jason Wang]

On 2021/3/2 5:51 下午, Michael S. Tsirkin wrote:
> On Tue, Mar 02, 2021 at 04:14:18AM -0500, Jason Wang wrote:
> > When CAP_IPC_LOCK is set we should not check locked memory against
> > rlimit as what has been implemented in mlock().
> >
> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> Indeed and it's not just mlock.
>
> Documentation/admin-guide/perf-security.rst:
>
> RLIMIT_MEMLOCK and perf_event_mlock_kb resource constraints are ignored
> for processes with the CAP_IPC_LOCK capability.
>
> and let's add a Fixes: tag?


Sure, V2 is posted.

Thanks


> > ---
> >   drivers/vhost/vdpa.c | 3 ++-
> >   1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> > index ef688c8c0e0e..e93572e2e344 100644
> > --- a/drivers/vhost/vdpa.c
> > +++ b/drivers/vhost/vdpa.c
> > @@ -638,7 +638,8 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
> >   	mmap_read_lock(dev->mm);
> >   
> >   	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
> > -	if (npages + atomic64_read(&dev->mm->pinned_vm) > lock_limit) {
> > +	if (!capable(CAP_IPC_LOCK) &&
> > +	    (npages + atomic64_read(&dev->mm->pinned_vm) > lock_limit)) {
> >   		ret = -ENOMEM;
> >   		goto unlock;
> >   	}
> > --
> > 2.18.1