[PATCH v1 2/2] xen/domain: introduce generic weak function for domain struct allocation

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

From: Roger Pau Monne <roger.pau@xxxxxxxxxx>

x86 has specific requirements about the allocation of the domain structure,
but that's not the case for ARM or likely other architectures.

Introduce a generic weak function that can be overwritten with an
architecture specific implementation if required.

No functional change intended.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Reviewed-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
Changes:
 - Add Reviewed-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>.
 - Add empty line before last return in alloc_domain_struct().
---
 xen/arch/arm/domain.c  | 12 ------------
 xen/arch/ppc/stubs.c   |  5 -----
 xen/arch/riscv/stubs.c |  5 -----
 xen/common/domain.c    | 14 ++++++++++++++
 4 files changed, 14 insertions(+), 22 deletions(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 45aeb8bddc..29588f869c 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -479,18 +479,6 @@ void startup_cpu_idle_loop(void)
     reset_stack_and_jump(idle_loop);
 }
 
-struct domain *alloc_domain_struct(void)
-{
-    struct domain *d;
-    BUILD_BUG_ON(sizeof(*d) > PAGE_SIZE);
-    d = alloc_xenheap_pages(0, 0);
-    if ( d == NULL )
-        return NULL;
-
-    clear_page(d);
-    return d;
-}
-
 void free_domain_struct(struct domain *d)
 {
     free_xenheap_page(d);
diff --git a/xen/arch/ppc/stubs.c b/xen/arch/ppc/stubs.c
index 671e71aa0a..d999d22718 100644
--- a/xen/arch/ppc/stubs.c
+++ b/xen/arch/ppc/stubs.c
@@ -294,11 +294,6 @@ void vcpu_kick(struct vcpu *v)
     BUG_ON("unimplemented");
 }
 
-struct domain *alloc_domain_struct(void)
-{
-    BUG_ON("unimplemented");
-}
-
 struct vcpu *alloc_vcpu_struct(const struct domain *d)
 {
     BUG_ON("unimplemented");
diff --git a/xen/arch/riscv/stubs.c b/xen/arch/riscv/stubs.c
index e396b67cd3..155e5a7f58 100644
--- a/xen/arch/riscv/stubs.c
+++ b/xen/arch/riscv/stubs.c
@@ -268,11 +268,6 @@ void vcpu_kick(struct vcpu *v)
     BUG_ON("unimplemented");
 }
 
-struct domain *alloc_domain_struct(void)
-{
-    BUG_ON("unimplemented");
-}
-
 struct vcpu *alloc_vcpu_struct(const struct domain *d)
 {
     BUG_ON("unimplemented");
diff --git a/xen/common/domain.c b/xen/common/domain.c
index e566a18747..c134868e95 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -785,6 +785,20 @@ static int sanitise_domain_config(struct 
xen_domctl_createdomain *config)
     return arch_sanitise_domain_config(config);
 }
 
+struct domain *__weak alloc_domain_struct(void)
+{
+    struct domain *d = alloc_xenheap_pages(0, 0);
+
+    BUILD_BUG_ON(sizeof(*d) > PAGE_SIZE);
+
+    if ( !d )
+        return NULL;
+
+    clear_page(d);
+
+    return d;
+}
+
 struct domain *domain_create(domid_t domid,
                              struct xen_domctl_createdomain *config,
                              unsigned int flags)
-- 
2.49.0