unify update_runstate_area()

x86'es variant is a superset of Arm's, with CONFIG_COMPAT parts already
properly marked. The only other missing piece is
update_guest_memory_policy(): For the time being Arm simply gains an
empty struct and inline function.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>

xen/arch/arm/domain.c

@@ -281,38 +281,6 @@ static void ctxt_switch_to(struct vcpu *n)
     WRITE_SYSREG(n->arch.mdcr_el2, MDCR_EL2);
 }
 
-/* Update per-VCPU guest runstate shared memory area (if registered). */
-static void update_runstate_area(struct vcpu *v)
-{
-    void __user *guest_handle = NULL;
-    struct vcpu_runstate_info runstate;
-
-    if ( guest_handle_is_null(runstate_guest(v)) )
-        return;
-
-    memcpy(&runstate, &v->runstate, sizeof(runstate));
-
-    if ( VM_ASSIST(v->domain, runstate_update_flag) )
-    {
-        guest_handle = &v->runstate_guest.p->state_entry_time + 1;
-        guest_handle--;
-        runstate.state_entry_time |= XEN_RUNSTATE_UPDATE;
-        __raw_copy_to_guest(guest_handle,
-                            (void *)(&runstate.state_entry_time + 1) - 1, 1);
-        smp_wmb();
-    }
-
-    __copy_to_guest(runstate_guest(v), &runstate, 1);
-
-    if ( guest_handle )
-    {
-        runstate.state_entry_time &= ~XEN_RUNSTATE_UPDATE;
-        smp_wmb();
-        __raw_copy_to_guest(guest_handle,
-                            (void *)(&runstate.state_entry_time + 1) - 1, 1);
-    }
-}
-
 static void schedule_tail(struct vcpu *prev)
 {
     ASSERT(prev != current);

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

@@ -295,6 +295,11 @@ struct arch_vcpu_io {
     struct instr_details dabt_instr; /* when the instruction is decoded */
 };
 
+struct guest_memory_policy {};
+static inline void update_guest_memory_policy(struct vcpu *v,
+                                              struct guest_memory_policy *gmp)
+{}
+
 #endif /* __ASM_DOMAIN_H__ */
 
 /*

xen/arch/x86/domain.c

@@ -1831,64 +1831,6 @@ void cf_check paravirt_ctxt_switch_to(struct vcpu *v)
         wrmsr_tsc_aux(v->arch.msrs->tsc_aux);
 }
 
-/* Update per-VCPU guest runstate shared memory area (if registered). */
-bool update_runstate_area(struct vcpu *v)
-{
-    bool rc;
-    struct guest_memory_policy policy = { .nested_guest_mode = false };
-    void __user *guest_handle = NULL;
-    struct vcpu_runstate_info runstate;
-
-    if ( guest_handle_is_null(runstate_guest(v)) )
-        return true;
-
-    update_guest_memory_policy(v, &policy);
-
-    memcpy(&runstate, &v->runstate, sizeof(runstate));
-
-    if ( VM_ASSIST(v->domain, runstate_update_flag) )
-    {
-#ifdef CONFIG_COMPAT
-        guest_handle = has_32bit_shinfo(v->domain)
-            ? &v->runstate_guest.compat.p->state_entry_time + 1
-            : &v->runstate_guest.native.p->state_entry_time + 1;
-#else
-        guest_handle = &v->runstate_guest.p->state_entry_time + 1;
-#endif
-        guest_handle--;
-        runstate.state_entry_time |= XEN_RUNSTATE_UPDATE;
-        __raw_copy_to_guest(guest_handle,
-                            (void *)(&runstate.state_entry_time + 1) - 1, 1);
-        smp_wmb();
-    }
-
-#ifdef CONFIG_COMPAT
-    if ( has_32bit_shinfo(v->domain) )
-    {
-        struct compat_vcpu_runstate_info info;
-
-        XLAT_vcpu_runstate_info(&info, &runstate);
-        __copy_to_guest(v->runstate_guest.compat, &info, 1);
-        rc = true;
-    }
-    else
-#endif
-        rc = __copy_to_guest(runstate_guest(v), &runstate, 1) !=
-             sizeof(runstate);
-
-    if ( guest_handle )
-    {
-        runstate.state_entry_time &= ~XEN_RUNSTATE_UPDATE;
-        smp_wmb();
-        __raw_copy_to_guest(guest_handle,
-                            (void *)(&runstate.state_entry_time + 1) - 1, 1);
-    }
-
-    update_guest_memory_policy(v, &policy);
-
-    return rc;
-}
-
 static void _update_runstate_area(struct vcpu *v)
 {
     if ( !update_runstate_area(v) && is_pv_vcpu(v) &&

xen/arch/x86/include/asm/domain.h

@@ -681,7 +681,6 @@ void update_guest_memory_policy(struct vcpu *v,
 
 void domain_cpu_policy_changed(struct domain *d);
 
-bool update_runstate_area(struct vcpu *);
 bool update_secondary_system_time(struct vcpu *,
                                   struct vcpu_time_info *);
 

xen/common/domain.c

@@ -1592,6 +1592,64 @@ int default_initialise_vcpu(struct vcpu *v, XEN_GUEST_HANDLE_PARAM(void) arg)
     return rc;
 }
 
+/* Update per-VCPU guest runstate shared memory area (if registered). */
+bool update_runstate_area(struct vcpu *v)
+{
+    bool rc;
+    struct guest_memory_policy policy = { };
+    void __user *guest_handle = NULL;
+    struct vcpu_runstate_info runstate;
+
+    if ( guest_handle_is_null(runstate_guest(v)) )
+        return true;
+
+    update_guest_memory_policy(v, &policy);
+
+    memcpy(&runstate, &v->runstate, sizeof(runstate));
+
+    if ( VM_ASSIST(v->domain, runstate_update_flag) )
+    {
+#ifdef CONFIG_COMPAT
+        guest_handle = has_32bit_shinfo(v->domain)
+            ? &v->runstate_guest.compat.p->state_entry_time + 1
+            : &v->runstate_guest.native.p->state_entry_time + 1;
+#else
+        guest_handle = &v->runstate_guest.p->state_entry_time + 1;
+#endif
+        guest_handle--;
+        runstate.state_entry_time |= XEN_RUNSTATE_UPDATE;
+        __raw_copy_to_guest(guest_handle,
+                            (void *)(&runstate.state_entry_time + 1) - 1, 1);
+        smp_wmb();
+    }
+
+#ifdef CONFIG_COMPAT
+    if ( has_32bit_shinfo(v->domain) )
+    {
+        struct compat_vcpu_runstate_info info;
+
+        XLAT_vcpu_runstate_info(&info, &runstate);
+        __copy_to_guest(v->runstate_guest.compat, &info, 1);
+        rc = true;
+    }
+    else
+#endif
+        rc = __copy_to_guest(runstate_guest(v), &runstate, 1) !=
+             sizeof(runstate);
+
+    if ( guest_handle )
+    {
+        runstate.state_entry_time &= ~XEN_RUNSTATE_UPDATE;
+        smp_wmb();
+        __raw_copy_to_guest(guest_handle,
+                            (void *)(&runstate.state_entry_time + 1) - 1, 1);
+    }
+
+    update_guest_memory_policy(v, &policy);
+
+    return rc;
+}
+
 long common_vcpu_op(int cmd, struct vcpu *v, XEN_GUEST_HANDLE_PARAM(void) arg)
 {
     long rc = 0;

xen/include/xen/domain.h

@@ -101,6 +101,8 @@ int default_initialise_vcpu(struct vcpu *v, XEN_GUEST_HANDLE_PARAM(void) arg);
 int arch_get_paging_mempool_size(struct domain *d, uint64_t *size /* bytes */);
 int arch_set_paging_mempool_size(struct domain *d, uint64_t size /* bytes */);
 
+bool update_runstate_area(struct vcpu *);
+
 int domain_relinquish_resources(struct domain *d);
 
 void dump_pageframe_info(struct domain *d);