Re: [PATCH] virtio_ring: switch to dma_XX barriers for rpmsg

From: Michael S. Tsirkin
Date: Thu Apr 19 2018 - 14:10:54 EST


On Thu, Apr 19, 2018 at 07:48:24PM +0200, Paolo Bonzini wrote:
> On 19/04/2018 19:46, Michael S. Tsirkin wrote:
> >> This should be okay, but I wonder if there should be a virtio_wmb(...)
> >> or an "if (weak_barriers) wmb()" before the "writel" in vm_notify
> >> (drivers/virtio/virtio_mmio.c).
> >>
> >> Thanks,
> >>
> >> Paolo
> > That one uses weak barriers AFAIK.
> >
> > IIUC you mean rproc_virtio_notify.
> >
> > I suspect it works because specific kick callbacks have a barrier internally.
>
> Yes, that one. At least keystone_rproc_kick doesn't seem to have a barrier.
>
> Paolo

Maybe it's wrong or not used with virtio then.
This patch won't change anything with respect to that though.

--
MST