[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH v5 1/8] xen/arm: introduce static shared memory



Hi Penny,

I have looked at the code and I have further questions about the binding.

On 20/06/2022 06:11, Penny Zheng wrote:
---
  docs/misc/arm/device-tree/booting.txt | 120 ++++++++++++++++++++++++++
  xen/arch/arm/Kconfig                  |   6 ++
  xen/arch/arm/bootfdt.c                |  68 +++++++++++++++
  xen/arch/arm/include/asm/setup.h      |   3 +
  4 files changed, 197 insertions(+)

diff --git a/docs/misc/arm/device-tree/booting.txt 
b/docs/misc/arm/device-tree/booting.txt
index 98253414b8..6467bc5a28 100644
--- a/docs/misc/arm/device-tree/booting.txt
+++ b/docs/misc/arm/device-tree/booting.txt
@@ -378,3 +378,123 @@ device-tree:
This will reserve a 512MB region starting at the host physical address
  0x30000000 to be exclusively used by DomU1.
+
+Static Shared Memory
+====================
+
+The static shared memory device tree nodes allow users to statically set up
+shared memory on dom0less system, enabling domains to do shm-based
+communication.
+
+- compatible
+
+    "xen,domain-shared-memory-v1"
+
+- xen,shm-id
+
+    An 8-bit integer that represents the unique identifier of the shared memory
+    region. The maximum identifier shall be "xen,shm-id = <0xff>".

There is nothing in Xen that will ensure that xen,shm-id will match for all the nodes using the same region.

I see you write it to the guest device-tree. However there is a mismatch of the type: here you use an integer whereas the guest binding is using a string.

Cheers,

--
Julien Grall



 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.