[PATCH 3/3] powerpc/pseries/vas: Disable window open during migration

[Haren Myneni]

The current partition migration implementation does not freeze the
user space and the user space can continue open VAS windows. So
when migration_in_progress flag is enabled, VAS open window
API returns -EBUSY.

Signed-off-by: Haren Myneni <ha...@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/vas.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/vas.c 
b/arch/powerpc/platforms/pseries/vas.c
index b53e3fe02971..63316c401abb 100644
--- a/arch/powerpc/platforms/pseries/vas.c
+++ b/arch/powerpc/platforms/pseries/vas.c
@@ -29,6 +29,7 @@ static bool copypaste_feat;
 
 static struct vas_caps vascaps[VAS_MAX_FEAT_TYPE];
 static DEFINE_MUTEX(vas_pseries_mutex);
+static bool migration_in_progress;
 
 static long hcall_return_busy_check(long rc)
 {
@@ -355,8 +356,11 @@ static struct vas_window *vas_allocate_window(int vas_id, 
u64 flags,
         * same fault IRQ is not freed by the OS before.
         */
        mutex_lock(&vas_pseries_mutex);
-       rc = allocate_setup_window(txwin, (u64 *)&domain[0],
-                                  cop_feat_caps->win_type);
+       if (migration_in_progress)
+               rc = -EBUSY;
+       else
+               rc = allocate_setup_window(txwin, (u64 *)&domain[0],
+                                          cop_feat_caps->win_type);
        mutex_unlock(&vas_pseries_mutex);
        if (rc)
                goto out;
@@ -893,6 +897,11 @@ int vas_migration_handler(int action)
 
        mutex_lock(&vas_pseries_mutex);
 
+       if (action == VAS_SUSPEND)
+               migration_in_progress = true;
+       else
+               migration_in_progress = false;
+
        for (i = 0; i < VAS_MAX_FEAT_TYPE; i++) {
                vcaps = &vascaps[i];
                caps = &vcaps->caps;
-- 
2.27.0