Fix: Communication from UP SP to MP SP
Issued direct message request from UP SP to MP SP. When handling the
direct response from MP SP, the SPMC would try to access a vCPU
structure from the receiver VM's (UP SP) that hasn't been initialized.
This issue has been addressed with function 'api_ffa_get_vm_vcpu',
already used when handling direct message request, it is now used
handling direct messaging response. It checks the number of
vCPUs of the target VM, before attempting to access the structure given
by an index.
Change-Id: I5474177d3b36f34e7db54b5af2f813788e14f2d2
Signed-off-by: J-Alves <joao.alves@arm.com>
diff --git a/src/api.c b/src/api.c
index fa5c9b7..a675784 100644
--- a/src/api.c
+++ b/src/api.c
@@ -65,6 +65,25 @@
}
/**
+ * Get target VM vCPU:
+ * If VM is UP then return first vCPU.
+ * If VM is MP then return vCPU whose index matches current CPU index.
+ */
+static struct vcpu *api_ffa_get_vm_vcpu(struct vm *vm, struct vcpu *current)
+{
+ ffa_vcpu_index_t current_cpu_index = cpu_index(current->cpu);
+ struct vcpu *vcpu = NULL;
+
+ if (vm->vcpu_count == 1) {
+ vcpu = vm_get_vcpu(vm, 0);
+ } else if (current_cpu_index < vm->vcpu_count) {
+ vcpu = vm_get_vcpu(vm, current_cpu_index);
+ }
+
+ return vcpu;
+}
+
+/**
* Switches the physical CPU back to the corresponding vCPU of the VM whose ID
* is given as argument of the function.
*
@@ -72,7 +91,7 @@
* is SPMC), and on the context of the remaining 'api_switch_to_*' functions.
*
* This function works for partitions that are:
- * - UP non-migratable.
+ * - UP migratable.
* - MP with pinned Execution Contexts.
*/
static struct vcpu *api_switch_to_vm(struct vcpu *current,
@@ -81,7 +100,7 @@
ffa_vm_id_t to_id)
{
struct vm *to_vm = vm_find(to_id);
- struct vcpu *next = vm_get_vcpu(to_vm, cpu_index(current->cpu));
+ struct vcpu *next = api_ffa_get_vm_vcpu(to_vm, current);
CHECK(next != NULL);
@@ -1632,26 +1651,6 @@
}
/**
- * Get target VM vCPU for direct messaging request.
- * If VM is UP then return first vCPU.
- * If VM is MP then return vCPU whose index matches current CPU index.
- */
-static struct vcpu *api_ffa_msg_send_direct_get_receiver_vcpu(
- struct vm *vm, struct vcpu *current)
-{
- ffa_vcpu_index_t current_cpu_index = cpu_index(current->cpu);
- struct vcpu *vcpu = NULL;
-
- if (vm->vcpu_count == 1) {
- vcpu = vm_get_vcpu(vm, 0);
- } else if (current_cpu_index < vm->vcpu_count) {
- vcpu = vm_get_vcpu(vm, current_cpu_index);
- }
-
- return vcpu;
-}
-
-/**
* FF-A specification states that x2/w2 Must Be Zero for direct messaging
* interfaces.
*/
@@ -1734,8 +1733,7 @@
* number of PEs in the system. It further states that MP partitions
* accepting direct request messages cannot migrate.
*/
- receiver_vcpu =
- api_ffa_msg_send_direct_get_receiver_vcpu(receiver_vm, current);
+ receiver_vcpu = api_ffa_get_vm_vcpu(receiver_vm, current);
if (receiver_vcpu == NULL) {
return ffa_error(FFA_INVALID_PARAMETERS);
}