[xen staging] tools/xenstored: make stubdom_init() live update aware

[patchbot@xxxxxxx]

commit e3c2af4ccd61dea681962466909c350d96b7803f
Author:     Juergen Gross <jgross@xxxxxxxx>
AuthorDate: Thu Jul 31 09:45:59 2025 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Jul 31 09:45:59 2025 +0200

    tools/xenstored: make stubdom_init() live update aware
    
    Pass the live_update bool to stubdom_init() in order to be able to
    handle it properly under Mini-OS.
    
    As stubdom_init() will (re-)create the 9pfs device needed for
    reading the saved state, call stubdom_init() before lu_read_state().
    
    Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
    Reviewed-by: Jason Andryuk <jason.andryuk@xxxxxxx>
---
 tools/xenstored/core.c   |  4 ++--
 tools/xenstored/core.h   |  2 +-
 tools/xenstored/domain.c | 15 +++++++++------
 tools/xenstored/domain.h |  2 +-
 tools/xenstored/minios.c | 12 +++++++++---
 5 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/tools/xenstored/core.c b/tools/xenstored/core.c
index e3e8607592..5377d72f54 100644
--- a/tools/xenstored/core.c
+++ b/tools/xenstored/core.c
@@ -2774,14 +2774,14 @@ int main(int argc, char *argv[])
        if (tracefile)
                tracefile = absolute_filename(NULL, tracefile);
 
+       stubdom_init(live_update);
+
 #ifndef NO_LIVE_UPDATE
        /* Read state in case of live update. */
        if (live_update)
                lu_read_state();
 #endif
 
-       stubdom_init();
-
        check_store();
 
        /* Get ready to listen to the tools. */
diff --git a/tools/xenstored/core.h b/tools/xenstored/core.h
index 3f7426fbe3..5071f1dedd 100644
--- a/tools/xenstored/core.h
+++ b/tools/xenstored/core.h
@@ -412,7 +412,7 @@ xenevtchn_handle *evtchn_fdopen(int fd);
 int evtchn_rebind(int port);
 
 #ifdef __MINIOS__
-void mount_9pfs(void);
+void mount_9pfs(bool live_update);
 #endif
 
 const char *xenstore_rundir(void);
diff --git a/tools/xenstored/domain.c b/tools/xenstored/domain.c
index 34bf7f9c82..34ebeaac9b 100644
--- a/tools/xenstored/domain.c
+++ b/tools/xenstored/domain.c
@@ -1337,7 +1337,7 @@ void dom0_init(void)
        xenevtchn_notify(xce_handle, dom0->port);
 }
 
-void stubdom_init(void)
+void stubdom_init(bool live_update)
 {
 #ifdef __MINIOS__
        struct domain *stubdom;
@@ -1345,13 +1345,16 @@ void stubdom_init(void)
        if (stub_domid < 0)
                return;
 
-       stubdom = introduce_domain(NULL, stub_domid, xenbus_evtchn, false);
-       if (!stubdom)
-               barf_perror("Failed to initialize stubdom");
+       if (!live_update) {
+               stubdom = introduce_domain(NULL, stub_domid, xenbus_evtchn,
+                                          false);
+               if (!stubdom)
+                       barf_perror("Failed to initialize stubdom");
 
-       xenevtchn_notify(xce_handle, stubdom->port);
+               xenevtchn_notify(xce_handle, stubdom->port);
+       }
 
-       mount_9pfs();
+       mount_9pfs(live_update);
 #endif
 }
 
diff --git a/tools/xenstored/domain.h b/tools/xenstored/domain.h
index 94481fdcc0..3ca702f56d 100644
--- a/tools/xenstored/domain.h
+++ b/tools/xenstored/domain.h
@@ -93,7 +93,7 @@ int do_set_feature(const void *ctx, struct connection *conn,
 void domain_early_init(void);
 void domain_init(int evtfd);
 void dom0_init(void);
-void stubdom_init(void);
+void stubdom_init(bool live_update);
 void domain_deinit(void);
 void ignore_connection(struct connection *conn, unsigned int err);
 
diff --git a/tools/xenstored/minios.c b/tools/xenstored/minios.c
index ec5faebaf3..f04423fe09 100644
--- a/tools/xenstored/minios.c
+++ b/tools/xenstored/minios.c
@@ -131,15 +131,21 @@ static void mount_thread(void *p)
                free(err);
        }
 
-       p9_device = init_9pfront(0, XENSTORE_LIB_DIR);
+       p9_device = init_9pfront2(0, XENSTORE_LIB_DIR, INIT9P_FLAG_KEXEC);
 
        /* Start logging if selected. */
        reopen_log();
 }
 
-void mount_9pfs(void)
+void mount_9pfs(bool live_update)
 {
-       create_thread("mount-9pfs", mount_thread, NULL);
+       if (!live_update)
+               create_thread("mount-9pfs", mount_thread, NULL);
+       else {
+               p9_device = init_9pfront2(0, XENSTORE_LIB_DIR,
+                                         INIT9P_FLAG_REINIT);
+               reopen_log();
+       }
 }
 
 const char *xenstore_rundir(void)
--
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