RDMA/core: Add the core support field to METHOD_GET_CONTEXT

Add the core support field to METHOD_GET_CONTEXT, this field should
represent capabilities that are not device-specific.

Return support for optional access flags for memory regions. User-space
will use this capability to mask the optional access flags for
unsupporting kernels.

Link: https://lore.kernel.org/r/1578506740-22188-10-git-send-email-yishaih@mellanox.com
Signed-off-by: Michael Guralnik <michaelgur@mellanox.com>
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/uverbs_std_types_device.c

@@ -204,6 +204,7 @@ static int UVERBS_HANDLER(UVERBS_METHOD_GET_CONTEXT)(
 	struct uverbs_attr_bundle *attrs)
 {
 	u32 num_comp = attrs->ufile->device->num_comp_vectors;
+	u64 core_support = IB_UVERBS_CORE_SUPPORT_OPTIONAL_MR_ACCESS;
 	int ret;
 
 	ret = uverbs_copy_to(attrs, UVERBS_ATTR_GET_CONTEXT_NUM_COMP_VECTORS,
@@ -211,6 +212,11 @@ static int UVERBS_HANDLER(UVERBS_METHOD_GET_CONTEXT)(
 	if (IS_UVERBS_COPY_ERR(ret))
 		return ret;
 
+	ret = uverbs_copy_to(attrs, UVERBS_ATTR_GET_CONTEXT_CORE_SUPPORT,
+			     &core_support, sizeof(core_support));
+	if (IS_UVERBS_COPY_ERR(ret))
+		return ret;
+
 	ret = ib_alloc_ucontext(attrs);
 	if (ret)
 		return ret;
@@ -227,6 +233,8 @@ DECLARE_UVERBS_NAMED_METHOD(
 	UVERBS_METHOD_GET_CONTEXT,
 	UVERBS_ATTR_PTR_OUT(UVERBS_ATTR_GET_CONTEXT_NUM_COMP_VECTORS,
 			    UVERBS_ATTR_TYPE(u32), UA_OPTIONAL),
+	UVERBS_ATTR_PTR_OUT(UVERBS_ATTR_GET_CONTEXT_CORE_SUPPORT,
+			    UVERBS_ATTR_TYPE(u64), UA_OPTIONAL),
 	UVERBS_ATTR_UHW());
 
 DECLARE_UVERBS_NAMED_METHOD(

include/uapi/rdma/ib_user_ioctl_cmds.h

@@ -84,6 +84,7 @@ enum uverbs_attrs_query_port_cmd_attr_ids {
 
 enum uverbs_attrs_get_context_attr_ids {
 	UVERBS_ATTR_GET_CONTEXT_NUM_COMP_VECTORS,
+	UVERBS_ATTR_GET_CONTEXT_CORE_SUPPORT,
 };
 
 enum uverbs_attrs_create_cq_cmd_attr_ids {

include/uapi/rdma/ib_user_ioctl_verbs.h

@@ -44,6 +44,10 @@
 #define IB_UVERBS_ACCESS_OPTIONAL_FIRST (1 << 20)
 #define IB_UVERBS_ACCESS_OPTIONAL_LAST (1 << 29)
 
+enum ib_uverbs_core_support {
+	IB_UVERBS_CORE_SUPPORT_OPTIONAL_MR_ACCESS = 1 << 0,
+};
+
 enum ib_uverbs_access_flags {
 	IB_UVERBS_ACCESS_LOCAL_WRITE = 1 << 0,
 	IB_UVERBS_ACCESS_REMOTE_WRITE = 1 << 1,