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docs: update the xenstore migration stream documentation
For live update of Xenstore some records defined in the migration stream document need to be changed: - Support of the read-only socket has been dropped from all Xenstore implementations, so ro-socket-fd in the global record can be removed. - Some guests require the event channel to Xenstore to remain the same on Xenstore side, so Xenstore has to keep the event channel interface open across a live update. For this purpose an evtchn-fd needs to be added to the global record. - With no read-only support the flags field in the connection record can be dropped. - The evtchn field in the connection record needs to be switched to hold the port of the Xenstore side of the event channel. - A flags field needs to be added to permission specifiers in order to be able to mark a permission as stale (XSA-322). Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Julien Grall <jgrall@amazon.com>
This commit is contained in:
Juergen Gross authored and Andrew Cooper committed
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commit
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@@ -116,7 +116,7 @@ xenstored state that needs to be restored.
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+-------+-------+-------+-------+
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| rw-socket-fd |
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+-------------------------------+
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| ro-socket-fd |
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| evtchn-fd |
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+-------------------------------+
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```
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@@ -126,8 +126,8 @@ xenstored state that needs to be restored.
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| `rw-socket-fd` | The file descriptor of the socket accepting |
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| | read-write connections |
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| | |
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| `ro-socket-fd` | The file descriptor of the socket accepting |
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| | read-only connections |
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| `evtchn-fd` | The file descriptor used to communicate with |
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| | the event channel driver |
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xenstored will resume in the original process context. Hence `rw-socket-fd` and
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`ro-socket-fd` simply specify the file descriptors of the sockets. Sockets
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@@ -147,7 +147,7 @@ the domain being migrated.
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```
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0 1 2 3 4 5 6 7 octet
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+-------+-------+-------+-------+-------+-------+-------+-------+
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| conn-id | conn-type | flags |
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| conn-id | conn-type | |
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+-------------------------------+---------------+---------------+
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| conn-spec
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...
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@@ -169,9 +169,6 @@ the domain being migrated.
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| | 0x0001: socket |
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| | 0x0002 - 0xFFFF: reserved for future use |
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| | |
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| `flags` | A bit-wise OR of: |
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| | 0001: read-only |
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| | |
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| `conn-spec` | See below |
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| | |
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| `in-data-len` | The length (in octets) of any data read |
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@@ -216,7 +213,7 @@ For `shared ring` connections it is as follows:
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| | operation [2] or DOMID_INVALID [3] otherwise |
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| | |
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| `evtchn` | The port number of the interdomain channel used |
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| | by `domid` to communicate with xenstored |
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| | by xenstored to communicate with `domid` |
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| | |
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Since the ABI guarantees that entry 1 in `domid`'s grant table will always
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@@ -386,7 +383,7 @@ A node permission specifier has the following format:
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```
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0 1 2 3 octet
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+-------+-------+-------+-------+
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| perm | pad | domid |
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| perm | flags | domid |
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+-------+-------+---------------+
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```
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@@ -395,6 +392,10 @@ A node permission specifier has the following format:
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| `perm` | One of the ASCII values `w`, `r`, `b` or `n` as |
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| | specified for the `SET_PERMS` operation [2] |
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| | |
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| `flags` | A bit-wise OR of: |
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| | 0x01: stale permission, ignore when checking |
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| | permissions |
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| | |
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| `domid` | The domain-id to which the permission relates |
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Note that perm1 defines the domain owning the code. See [4] for more
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