[xen staging] xenoprof: adjust ordering of page sharing vs domain type setting

[patchbot@xxxxxxx]

commit 7f6a6e8c0a400d1a073b083fe0b7d25ef74b14e0
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon May 4 11:48:13 2020 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon May 4 11:48:13 2020 +0200

    xenoprof: adjust ordering of page sharing vs domain type setting
    
    Buffer pages should be shared with "ignored" or "active" guests only
    (besides, obviously, the primary profiling domain). Hence domain type
    should be set to "ignored" before unsharing from the primary domain
    (which implies even a previously "passive" domain may then access its
    buffers, albeit that's not very useful unless it gets promoted to
    "active" subsequently), i.e. such that no further writes of records to
    the buffer would occur, and (at least for consistency) also before
    sharing it (with the calling domain) from the XENOPROF_get_buffer path.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Wei Liu <wl@xxxxxxx>
---
 xen/common/xenoprof.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/xen/common/xenoprof.c b/xen/common/xenoprof.c
index b04726cb49..3dad5dfb38 100644
--- a/xen/common/xenoprof.c
+++ b/xen/common/xenoprof.c
@@ -372,8 +372,8 @@ static void reset_passive(struct domain *d)
     if ( x == NULL )
         return;
 
-    unshare_xenoprof_page_with_guest(x);
     x->domain_type = XENOPROF_DOMAIN_IGNORED;
+    unshare_xenoprof_page_with_guest(x);
 }
 
 static void reset_active_list(void)
@@ -654,6 +654,13 @@ static int 
xenoprof_op_get_buffer(XEN_GUEST_HANDLE_PARAM(void) arg)
         if ( ret < 0 )
             return ret;
     }
+    else
+    {
+        d->xenoprof->domain_ready = 0;
+        d->xenoprof->domain_type = XENOPROF_DOMAIN_IGNORED;
+    }
+
+    d->xenoprof->is_primary = (xenoprof_primary_profiler == d);
 
     ret = share_xenoprof_page_with_guest(
         d, virt_to_mfn(d->xenoprof->rawbuf), d->xenoprof->npages);
@@ -662,10 +669,6 @@ static int 
xenoprof_op_get_buffer(XEN_GUEST_HANDLE_PARAM(void) arg)
 
     xenoprof_reset_buf(d);
 
-    d->xenoprof->domain_type  = XENOPROF_DOMAIN_IGNORED;
-    d->xenoprof->domain_ready = 0;
-    d->xenoprof->is_primary   = (xenoprof_primary_profiler == current->domain);
-        
     xenoprof_get_buffer.nbuf = d->xenoprof->nbuf;
     xenoprof_get_buffer.bufsize = d->xenoprof->bufsize;
     if ( !paging_mode_translate(d) )
--
generated by git-patchbot for /home/xen/git/xen.git#staging