On Wed, 23 Nov 2016, Paul Durrant wrote:
> > -----Original Message-----
> > From: Jan Beulich [mailto:jbeul...@suse.com]
> > Sent: 23 November 2016 09:25
> > To: qemu-de...@nongnu.org
> > Cc: Anthony Perard <anthony.per...@citrix.com>; Paul Durrant
> > <paul.durr...@citrix.com>; Stefano Stabellini <sstabell...@kernel.org>; xen-
> > devel <xen-de...@lists.xenproject.org>
> > Subject: [PATCH 3/3] xen: ignore direction in bufioreq handling
> >
> > There's no way to communicate back read data, so only writes can ever
> > be usefully specified. Ignore the field, paving the road for eventually
> > re-using the bit for something else in a few (many?) years time.
> >
> > Signed-off-by: Jan Beulich <jbeul...@suse.com>
>
> Reviewed-by: Paul Durrant <paul.durr...@citrix.com>
Acked-by: Stefano Stabellini <sstabell...@kernel.org>
> >
> > --- a/xen-hvm.c
> > +++ b/xen-hvm.c
> > @@ -997,6 +997,7 @@ static int handle_buffered_iopage(XenIOS
> > memset(&req, 0x00, sizeof(req));
> > req.state = STATE_IOREQ_READY;
> > req.count = 1;
> > + req.dir = IOREQ_WRITE;
> >
> > for (;;) {
> > uint32_t rdptr = buf_page->read_pointer, wrptr;
> > @@ -1014,7 +1015,6 @@ static int handle_buffered_iopage(XenIOS
> > req.size = 1U << buf_req->size;
> > req.addr = buf_req->addr;
> > req.data = buf_req->data;
> > - req.dir = buf_req->dir;
> > req.type = buf_req->type;
> > xen_rmb();
> > qw = (req.size == 8);
> > @@ -1031,10 +1031,12 @@ static int handle_buffered_iopage(XenIOS
> > handle_ioreq(state, &req);
> >
> > /* Only req.data may get updated by handle_ioreq(), albeit even
> > that
> > - * should not happen as such data would never make it to the guest.
> > + * should not happen as such data would never make it to the guest
> > (we
> > + * can only usefully see writes here after all).
> > */
> > assert(req.state == STATE_IOREQ_READY);
> > assert(req.count == 1);
> > + assert(req.dir == IOREQ_WRITE);
> > assert(!req.data_is_ptr);
> >
> > atomic_add(&buf_page->read_pointer, qw + 1);
> >
> >
>
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