Re: [Xen-devel] [PATCH 1/7] xen: import new ring macros in ring.h

From: Julien Grall
Date: Wed Mar 08 2017 - 06:41:23 EST


Hi Stefano,

On 08/03/17 00:12, Stefano Stabellini wrote:
On Tue, 7 Mar 2017, Julien Grall wrote:
Hi Stefano,

On 03/06/2017 08:01 PM, Stefano Stabellini wrote:
Sync the ring.h file with upstream Xen, to introduce the new ring macros.
They will be used by the Xen transport for 9pfs.

Signed-off-by: Stefano Stabellini <stefano@xxxxxxxxxxx>
CC: konrad.wilk@xxxxxxxxxx
CC: boris.ostrovsky@xxxxxxxxxx
CC: jgross@xxxxxxxx

---
NB: The new macros have not been committed to Xen yet. Do not apply this
patch until they do.
---
---
include/xen/interface/io/ring.h | 131
++++++++++++++++++++++++++++++++++++++++
1 file changed, 131 insertions(+)

diff --git a/include/xen/interface/io/ring.h
b/include/xen/interface/io/ring.h
index 21f4fbd..e16aa92 100644
--- a/include/xen/interface/io/ring.h
+++ b/include/xen/interface/io/ring.h

[...]

+#define XEN_FLEX_RING_SIZE(order)
\
+ (1UL << (order + PAGE_SHIFT - 1))

This will need to be XEN_PAGE_SHIFT in order to works with 64K kernel.

Good point! I had it right at the beginning but I lost the change in one
of the updates from xen.git.

It is probably worth to consider introducing XEN_PAGE_SIZE in the hypervisor code because we are likely to miss the change when the headers will be re-sync in the future.

Cheers,

--
Julien Grall