On 1/20/26 14:17, Stanislav Kinsburskii wrote:
On Mon, Jan 19, 2026 at 10:42:24PM -0800, Mukesh R wrote:
From: Mukesh Rathor <[email protected]>

Import/copy from Hyper-V public headers, definitions and declarations that
are related to attaching and detaching of device domains and interrupt
remapping, and building device ids for those purposes.

Signed-off-by: Mukesh Rathor <[email protected]>
---
  include/hyperv/hvgdk_mini.h |  11 ++++
  include/hyperv/hvhdk_mini.h | 112 ++++++++++++++++++++++++++++++++++++
  2 files changed, 123 insertions(+)


<snip>

+/* ID for stage 2 default domain and NULL domain */
+#define HV_DEVICE_DOMAIN_ID_S2_DEFAULT 0
+#define HV_DEVICE_DOMAIN_ID_S2_NULL    0xFFFFFFFFULL
+
+union hv_device_domain_id {
+       u64 as_uint64;
+       struct {
+               u32 type : 4;
+               u32 reserved : 28;
+               u32 id;
+       };
+} __packed;

Shouldn't the inner struct be packed instead?

+
+struct hv_input_device_domain { /* HV_INPUT_DEVICE_DOMAIN */
+       u64 partition_id;
+       union hv_input_vtl owner_vtl;
+       u8 padding[7];
+       union hv_device_domain_id domain_id;
+} __packed;
+
+union hv_create_device_domain_flags {  /* HV_CREATE_DEVICE_DOMAIN_FLAGS */
+       u32 as_uint32;
+       struct {
+               u32 forward_progress_required : 1;
+               u32 inherit_owning_vtl : 1;
+               u32 reserved : 30;
+       } __packed;
+} __packed;

Why should the union be packed?

From GCC docs:

Specifying this attribute for struct and union types is equivalent to
specifying the packed attribute on each of the structure or union members.

Thanks,
-Mukesh



Thanks,
Stanislav

+
+struct hv_input_create_device_domain { /* HV_INPUT_CREATE_DEVICE_DOMAIN */
+       struct hv_input_device_domain device_domain;
+       union hv_create_device_domain_flags create_device_domain_flags;
+} __packed;
+
+struct hv_input_delete_device_domain { /* HV_INPUT_DELETE_DEVICE_DOMAIN */
+       struct hv_input_device_domain device_domain;
+} __packed;
+
+struct hv_input_attach_device_domain { /* HV_INPUT_ATTACH_DEVICE_DOMAIN */
+       struct hv_input_device_domain device_domain;
+       union hv_device_id device_id;
+} __packed;
+
+struct hv_input_detach_device_domain { /* HV_INPUT_DETACH_DEVICE_DOMAIN */
+       u64 partition_id;
+       union hv_device_id device_id;
+} __packed;
+
+struct hv_input_map_device_gpa_pages { /* HV_INPUT_MAP_DEVICE_GPA_PAGES */
+       struct hv_input_device_domain device_domain;
+       union hv_input_vtl target_vtl;
+       u8 padding[3];
+       u32 map_flags;
+       u64 target_device_va_base;
+       u64 gpa_page_list[];
+} __packed;
+
+struct hv_input_unmap_device_gpa_pages {  /* HV_INPUT_UNMAP_DEVICE_GPA_PAGES */
+       struct hv_input_device_domain device_domain;
+       u64 target_device_va_base;
+} __packed;
+
  #endif /* _HV_HVHDK_MINI_H */
--
2.51.2.vfs.0.1



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