[Xen-devel] [PATCH v2 2/6] xen/arm: optee: check for preemption while freeing shared buffers

[Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>]

We can check for hypercall_preempt_check() in the loop inside
optee_relinquish_resources() to increase hypervisor responsiveness in
case if preemption is required.

Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>

---

Changes from v1:
 - Removed extra hypercall_preempt_check()
 - Updated the commit message
---
 xen/arch/arm/tee/optee.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/xen/arch/arm/tee/optee.c b/xen/arch/arm/tee/optee.c
index d64e9c3b85..55d11b91a9 100644
--- a/xen/arch/arm/tee/optee.c
+++ b/xen/arch/arm/tee/optee.c
@@ -633,17 +633,14 @@ static int optee_relinquish_resources(struct domain *d)
     list_for_each_entry_safe( shm_rpc, shm_rpc_tmp, &ctx->shm_rpc_list, list )
         free_shm_rpc(ctx, shm_rpc->cookie);
 
-    if ( hypercall_preempt_check() )
-        return -ERESTART;
-
-    /*
-     * TODO: Guest can pin up to MAX_TOTAL_SMH_BUF_PG pages and all of
-     * them will be put in this loop. It is worth considering to
-     * check for preemption inside the loop.
-     */
     list_for_each_entry_safe( optee_shm_buf, optee_shm_buf_tmp,
                               &ctx->optee_shm_buf_list, list )
+    {
+        if ( hypercall_preempt_check() )
+            return -ERESTART;
+
         free_optee_shm_buf(ctx, optee_shm_buf->cookie);
+    }
 
     if ( hypercall_preempt_check() )
         return -ERESTART;
-- 
2.22.0

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