xen/arm: add TEE teardown to arch_domain_teardown()

Adds a progress state for tee_domain_teardown() to be called from
arch_domain_teardown(). tee_domain_teardown() calls the new callback
domain_teardown() in struct tee_mediator_ops.

Note that the OP-TEE mediator should be updated in a future patch to use
the new teardown facility, that is not done here.

Co-developed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>

xen/arch/arm/domain.c

@@ -795,6 +795,41 @@ fail:
 
 int arch_domain_teardown(struct domain *d)
 {
+    int ret = 0;
+
+    BUG_ON(!d->is_dying);
+
+    /* See domain_teardown() for an explanation of all of this magic. */
+    switch ( d->teardown.arch_val )
+    {
+#define PROGRESS(x)                             \
+        d->teardown.arch_val = PROG_ ## x;      \
+        fallthrough;                            \
+    case PROG_ ## x
+
+        enum {
+            PROG_none,
+            PROG_tee,
+            PROG_done,
+        };
+
+    case PROG_none:
+        BUILD_BUG_ON(PROG_none != 0);
+
+    PROGRESS(tee):
+        ret = tee_domain_teardown(d);
+        if ( ret )
+            return ret;
+
+    PROGRESS(done):
+        break;
+
+#undef PROGRESS
+
+    default:
+        BUG();
+    }
+
     return 0;
 }
 

xen/arch/arm/include/asm/tee/tee.h

@@ -34,6 +34,7 @@ struct tee_mediator_ops {
      * guest and create own structures for the new domain.
      */
     int (*domain_init)(struct domain *d);
+    int (*domain_teardown)(struct domain *d);
 
     /*
      * Called during domain destruction to relinquish resources used
@@ -62,6 +63,7 @@ struct tee_mediator_desc {
 
 bool tee_handle_call(struct cpu_user_regs *regs);
 int tee_domain_init(struct domain *d, uint16_t tee_type);
+int tee_domain_teardown(struct domain *d);
 int tee_relinquish_resources(struct domain *d);
 uint16_t tee_get_type(void);
 
@@ -93,6 +95,11 @@ static inline int tee_relinquish_resources(struct domain *d)
     return 0;
 }
 
+static inline int tee_domain_teardown(struct domain *d)
+{
+    return 0;
+}
+
 static inline uint16_t tee_get_type(void)
 {
     return XEN_DOMCTL_CONFIG_TEE_NONE;

xen/arch/arm/tee/optee.c

@@ -268,6 +268,11 @@ static int optee_domain_init(struct domain *d)
     return 0;
 }
 
+static int optee_domain_teardown(struct domain *d)
+{
+    return 0;
+}
+
 static uint64_t regpair_to_uint64(register_t reg0, register_t reg1)
 {
     return ((uint64_t)reg0 << 32) | (uint32_t)reg1;
@@ -1732,6 +1737,7 @@ static const struct tee_mediator_ops optee_ops =
 {
     .probe = optee_probe,
     .domain_init = optee_domain_init,
+    .domain_teardown = optee_domain_teardown,
     .relinquish_resources = optee_relinquish_resources,
     .handle_call = optee_handle_call,
 };

xen/arch/arm/tee/tee.c

@@ -52,6 +52,14 @@ int tee_domain_init(struct domain *d, uint16_t tee_type)
     return cur_mediator->ops->domain_init(d);
 }
 
+int tee_domain_teardown(struct domain *d)
+{
+    if ( !cur_mediator )
+        return 0;
+
+    return cur_mediator->ops->domain_teardown(d);
+}
+
 int tee_relinquish_resources(struct domain *d)
 {
     if ( !cur_mediator )