Hi Steward,
On 25/03/2025 17:27, Stewart Hildebrand wrote:
We expect mmio read handlers to leave the bits above the access size
zeroed. Add an ASSERT to check this aspect of read handler behavior.
Suggested-by: Roger Pau Monné <roger....@citrix.com>
Signed-off-by: Stewart Hildebrand <stewart.hildebr...@amd.com>
With one question below:
Acked-by: Julien Grall <jgr...@amazon.com>
---
v17->v18:
* no change
v16->v17:
* new patch
See
https://lore.kernel.org/xen-devel/bc6660ef-59f1-4514-9792-067d987e3...@xen.org/
Also see 7db7bd0f319f ("arm/vpci: honor access size when returning an error")
Also see xen/arch/arm/ioreq.c:handle_ioserv()
---
xen/arch/arm/io.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/xen/arch/arm/io.c b/xen/arch/arm/io.c
index 653428e16c1f..68b5dca70026 100644
--- a/xen/arch/arm/io.c
+++ b/xen/arch/arm/io.c
@@ -37,6 +37,8 @@ static enum io_state handle_read(const struct mmio_handler
*handler,
if ( !handler->ops->read(v, info, &r, handler->priv) )
return IO_ABORT;
+ ASSERT((r & ~GENMASK_ULL((1U << info->dabt.size) * 8 - 1, 0)) == 0);
OOI, I was expecing GENMASK to be sufficient because "r" is effectively
an "unsigned long". So any reason to use GENMASK_ULL?
Cheers,
--
Julien Grall
