[XEN PATCH v10 02/24] xen/arm: add TEE teardown to arch_domain_teardown()

[Jens Wiklander <jens.wiklander@xxxxxxxxxx>]

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@xxxxxxxxxx>
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>

---
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Julien Grall <julien@xxxxxxx>
CC: Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
CC: Bertrand Marquis <bertrand.marquis@xxxxxxx>
CC: Jens Wiklander <jens.wiklander@xxxxxxxxxx>

v9 -> v10

- Swapped Andrews tags in the commit message
- Added Bertand's tag
- Removed the erroneous unconditional break switch statement in
  arch_domain_teardown()
- Updated commit message to note that the OP-TEE mediator also should
  use the new teardown facility.
---
 xen/arch/arm/domain.c              | 35 ++++++++++++++++++++++++++++++
 xen/arch/arm/include/asm/tee/tee.h |  7 ++++++
 xen/arch/arm/tee/optee.c           |  6 +++++
 xen/arch/arm/tee/tee.c             |  8 +++++++
 4 files changed, 56 insertions(+)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 15d9709a97d2..3ae86ca620a4 100644
--- a/xen/arch/arm/domain.c
+++ b/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;
 }
 
diff --git a/xen/arch/arm/include/asm/tee/tee.h 
b/xen/arch/arm/include/asm/tee/tee.h
index f483986385c8..da324467e130 100644
--- a/xen/arch/arm/include/asm/tee/tee.h
+++ b/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;
diff --git a/xen/arch/arm/tee/optee.c b/xen/arch/arm/tee/optee.c
index 301d205a36c5..c91bd7d5ac25 100644
--- a/xen/arch/arm/tee/optee.c
+++ b/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,
 };
diff --git a/xen/arch/arm/tee/tee.c b/xen/arch/arm/tee/tee.c
index 3964a8a5cddf..ddd17506a9ff 100644
--- a/xen/arch/arm/tee/tee.c
+++ b/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 )
-- 
2.34.1