On 8/29/25 11:58 AM, Teddy Astie wrote:
xen_domain_handle_t is defined as a opaque 16-bytes blob, but is
commonly used by toolstack and guest as a big-endian encoded and
formatted UUID (alike RFC 9562).
Clarify the definition of the type to ensure the guest and toolstack
interprets this value correctly in a way consistent with existing users
(at least with XAPI, xl, libvirt, hvmloader and Linux).
Fixes: 30ce2a9295a5 ("Store an opaque handle (tools uuid) in the domain
structure")
Suggested-by: Andrew Cooper<andrew.coop...@citrix.com>
Signed-off-by: Teddy Astie<teddy.as...@vates.tech>
LGTM: Acked-by: Oleksii Kurochko<oleksii.kuroc...@gmail.com>
Thanks.
~ Oleksii
---
v2:
- introduced
---
CHANGELOG.md | 1 +
xen/include/public/xen.h | 7 +++++++
2 files changed, 8 insertions(+)
diff --git a/CHANGELOG.md b/CHANGELOG.md
index cd34ea87b8..8c4435c181 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ The format is based on [Keep a
Changelog](https://keepachangelog.com/en/1.0.0/)
- For x86, GCC 5.1 and Binutils 2.25, or Clang/LLVM 11
- For ARM32 and ARM64, GCC 5.1 and Binutils 2.25
- Linux based device model stubdomains are now fully supported.
+ - Clarify guest UUIDs as being big-endian encoded.
- On x86:
- Restrict the cache flushing done as a result of guest physical memory map
diff --git a/xen/include/public/xen.h b/xen/include/public/xen.h
index 82b9c05a76..a219ef870f 100644
--- a/xen/include/public/xen.h
+++ b/xen/include/public/xen.h
@@ -973,6 +973,13 @@ typedef struct dom0_vga_console_info {
#define xen_vga_console_info dom0_vga_console_info
#define xen_vga_console_info_t dom0_vga_console_info_t
+/*
+ * The domain handle is chosen by the toolstack, and intended to hold a UUID
+ * conforming to RFC 9562 (i.e. big endian).
+ *
+ * Certain cases (e.g. SMBios) transform it to a Microsoft GUID (little
+ * endian) for presentation to the guest.
+ */
typedef uint8_t xen_domain_handle_t[16];
__DEFINE_XEN_GUEST_HANDLE(uint8, uint8_t);
