[PATCH 2/6] xen/arm: ffa: Track hypervisor notifications in a bitmap

[Bertrand Marquis <bertrand.marquis@xxxxxxx>]

Hypervisor notifications are currently tracked with a dedicated
buff_full_pending boolean. That state only represents a single HYP
notification bit and keeps HYP bitmap handling tied to single-purpose
bookkeeping.

Replace the boolean with a hypervisor notification bitmap protected by
notif_lock. INFO_GET reports pending when the bitmap is non-zero, GET
returns and clears the HYP bitmap under the lock, and RX-buffer-full
sets FFA_NOTIF_RX_BUFFER_FULL in the bitmap instead of updating
separate state.

Initialize and clear the bitmap during domain lifecycle handling, and
use ctx->ffa_id for bitmap create and destroy so the notification state
stays tied to the cached FF-A endpoint ID.

No functional changes.

Signed-off-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
---
 xen/arch/arm/tee/ffa_notif.c   | 46 ++++++++++++++++++++++++++--------
 xen/arch/arm/tee/ffa_private.h |  9 +++++--
 2 files changed, 43 insertions(+), 12 deletions(-)

diff --git a/xen/arch/arm/tee/ffa_notif.c b/xen/arch/arm/tee/ffa_notif.c
index 07bc5cb3a430..d15119409a25 100644
--- a/xen/arch/arm/tee/ffa_notif.c
+++ b/xen/arch/arm/tee/ffa_notif.c
@@ -94,8 +94,15 @@ void ffa_handle_notification_info_get(struct cpu_user_regs 
*regs)
 
     notif_pending = test_and_clear_bool(ctx->notif.secure_pending);
     if ( IS_ENABLED(CONFIG_FFA_VM_TO_VM) )
+    {
         notif_pending |= test_and_clear_bool(ctx->notif.vm_pending);
 
+        spin_lock(&ctx->notif.notif_lock);
+        if ( ctx->notif.hyp_pending )
+            notif_pending = true;
+        spin_unlock(&ctx->notif.notif_lock);
+    }
+
     if ( notif_pending )
     {
         /* A pending global notification for the guest */
@@ -174,12 +181,17 @@ void ffa_handle_notification_get(struct cpu_user_regs 
*regs)
             w6 = resp.a6;
     }
 
-    if ( IS_ENABLED(CONFIG_FFA_VM_TO_VM) &&
-          flags & FFA_NOTIF_FLAG_BITMAP_HYP &&
-          test_and_clear_bool(ctx->notif.buff_full_pending) )
+    if ( IS_ENABLED(CONFIG_FFA_VM_TO_VM) )
     {
-        ACCESS_ONCE(ctx->notif.vm_pending) = false;
-        w7 = FFA_NOTIF_RX_BUFFER_FULL;
+        spin_lock(&ctx->notif.notif_lock);
+
+        if ( (flags & FFA_NOTIF_FLAG_BITMAP_HYP) && ctx->notif.hyp_pending )
+        {
+            w7 = ctx->notif.hyp_pending;
+            ctx->notif.hyp_pending = 0;
+        }
+
+        spin_unlock(&ctx->notif.notif_lock);
     }
 
     ffa_set_regs(regs, FFA_SUCCESS_32, 0, w2, w3, w4, w5, w6, w7);
@@ -207,12 +219,17 @@ int32_t ffa_handle_notification_set(struct cpu_user_regs 
*regs)
 void ffa_raise_rx_buffer_full(struct domain *d)
 {
     struct ffa_ctx *ctx = d->arch.tee;
+    uint32_t prev_bitmap;
 
     if ( !ctx )
         return;
 
-    ACCESS_ONCE(ctx->notif.buff_full_pending) = true;
-    if ( !test_and_set_bool(ctx->notif.vm_pending) )
+    spin_lock(&ctx->notif.notif_lock);
+    prev_bitmap = ctx->notif.hyp_pending;
+    ctx->notif.hyp_pending |= FFA_NOTIF_RX_BUFFER_FULL;
+    spin_unlock(&ctx->notif.notif_lock);
+
+    if ( !(prev_bitmap & FFA_NOTIF_RX_BUFFER_FULL) )
         inject_notif_pending(d);
 }
 #endif
@@ -426,12 +443,15 @@ void ffa_notif_init(void)
 
 int ffa_notif_domain_init(struct domain *d)
 {
+    struct ffa_ctx *ctx = d->arch.tee;
     int32_t res;
 
+    spin_lock_init(&ctx->notif.notif_lock);
+    ctx->notif.hyp_pending = 0;
+
     if ( fw_notif_enabled )
     {
-
-        res = ffa_notification_bitmap_create(ffa_get_vm_id(d), d->max_vcpus);
+        res = ffa_notification_bitmap_create(ctx->ffa_id, d->max_vcpus);
         if ( res )
             return -ENOMEM;
     }
@@ -441,10 +461,16 @@ int ffa_notif_domain_init(struct domain *d)
 
 void ffa_notif_domain_destroy(struct domain *d)
 {
+    struct ffa_ctx *ctx = d->arch.tee;
+
+    spin_lock(&ctx->notif.notif_lock);
+    ctx->notif.hyp_pending = 0;
+    spin_unlock(&ctx->notif.notif_lock);
+
     /*
      * Call bitmap_destroy even if bitmap create failed as the SPMC will
      * return a DENIED error that we will ignore.
      */
     if ( fw_notif_enabled )
-        ffa_notification_bitmap_destroy(ffa_get_vm_id(d));
+        ffa_notification_bitmap_destroy(ctx->ffa_id);
 }
diff --git a/xen/arch/arm/tee/ffa_private.h b/xen/arch/arm/tee/ffa_private.h
index c291f32b56ff..5693772481ed 100644
--- a/xen/arch/arm/tee/ffa_private.h
+++ b/xen/arch/arm/tee/ffa_private.h
@@ -340,9 +340,14 @@ struct ffa_ctx_notif {
     bool vm_pending;
 
     /*
-     * True if domain has buffer full notification pending
+     * Lock protecting the hypervisor-managed notification state.
      */
-    bool buff_full_pending;
+    spinlock_t notif_lock;
+
+    /*
+     * Bitmap of pending hypervisor notifications (for HYP bitmap queries).
+     */
+    uint32_t hyp_pending;
 };
 
 struct ffa_ctx {
-- 
2.53.0