On 11.03.25 10:43, Julien Grall wrote:
Hi Juergen,On 04/02/2025 11:34, Juergen Gross wrote:In order to close a race window for Xenstore live update when using the new unique_id of domains, the migration stream needs to contain this unique_id for each domain known by Xenstore. Signed-off-by: Juergen Gross <jgr...@suse.com> --- V8: - new patch --- docs/designs/xenstore-migration.md | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)diff --git a/docs/designs/xenstore-migration.md b/docs/designs/xenstore- migration.mdindex 082314bf72..fba691ee0d 100644 --- a/docs/designs/xenstore-migration.md +++ b/docs/designs/xenstore-migration.md @@ -156,7 +156,7 @@ the domain being migrated. ``` 0 1 2 3 4 5 6 7 octet +-------+-------+-------+-------+-------+-------+-------+-------+ -| conn-id | conn-type | | +| conn-id | conn-type | uniq-id-off | +-------------------------------+---------------+---------------+> | conn-spec> ...@@ -165,6 +165,9 @@ the domain being migrated. +---------------+---------------+-------------------------------+ | data ... ++---------------------------------------------------------------+ +| unique-id | ++---------------------------------------------------------------+ ``` @@ -178,6 +181,12 @@ the domain being migrated. | | 0x0001: socket | | | 0x0002 - 0xFFFF: reserved for future use | | | | +| `uniq-id-off` | The offset (in octets) of the `unique-id` | +| | field from the start of the record body. | +| | If 0, no `unique-id` field is present. | +| | Only needed for `shared ring` connection in | +| | live update streams. | +| | |Looking at the rest of the record, the unique ID would be past the in-data (length is 2-byte) and the out-data (length is 4-byte). So technically the offset would need 5-bytes. But here you are using 2-bytes. Can you explain why?
Good catch. I think I need to change this to be a flag indicating that the unique-id is present and located at the next 8-byte boundary after "data". Juergen
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