On 07.03.25 01:37, Andrew Cooper wrote:
On 06/03/2025 7:09 am, Jürgen Groß wrote:
On 05.03.25 23:57, Andrew Cooper wrote:
On 05/03/2025 8:52 am, Juergen Gross wrote:
The description of the Xenstore INTRODUCE command is still referencing
xend. Fix that.

While at it, make clear that the Xenstore implementation is allowed
to ignore the specified gfn and use the Xenstore reserved grant id
GNTTAB_RESERVED_XENSTORE instead.

Signed-off-by: Juergen Gross <jgr...@suse.com>
---
   docs/misc/xenstore.txt | 6 +++++-
   1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/docs/misc/xenstore.txt b/docs/misc/xenstore.txt
index 38015835b1..d894d24d11 100644
--- a/docs/misc/xenstore.txt
+++ b/docs/misc/xenstore.txt
@@ -286,7 +286,7 @@ TRANSACTION_END        F|
   INTRODUCE        <domid>|<gfn>|<evtchn>|?
       Notifies xenstored to communicate with this domain.
   -    INTRODUCE is currently only used by xend (during domain
+    INTRODUCE is currently only used by xen tools (during domain
       startup and various forms of restore and resume), and
       xenstored prevents its use other than by dom0.
   @@ -299,6 +299,10 @@ INTRODUCE        <domid>|<gfn>|<evtchn>|?
       for example passing a high-bit-set 32-bit gfn as an unsigned
       decimal will attempt to use 0x7fffffff instead (!).
   +    Xenstored might ignore the <gfn> value and use the reserved
+    grant table entry GNTTAB_RESERVED_XENSTORE instead for mapping
+    the Xenstore interface page of the guest.

I'd suggest making a stronger statement than this.

---
The <gfn> field is used by xenstoreds which use foreign mapping to
access the ring page.

Alternatively, Grant 1 (GNTTAB_RESERVED_XENSTORE) is reserved for the
same purpose, and is populated by the domain builder on behalf of the
guest.  This mechanism is preferred because reduces the permissions that
xenstored needs in order to function.

Both <gfn> and Grant 1 need to agree, because implementations of
xenstored will use one and ignore the other.

Fine with me.

Are you happy for me to adjust on commit, or do you want a v2 sending out?

~Andrew

I did send out V2:

https://lists.xen.org/archives/html/xen-devel/2025-03/msg00248.html


Juergen

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