[xen master] x86/domctl: Conditionalise x86 domctl using DCE rather than ifdef

[patchbot@xxxxxxx]

commit 5513bfd054dbbcd15dfa95fef698d24446ff1f84
Author:     Alejandro Vallejo <alejandro.garciavallejo@xxxxxxx>
AuthorDate: Thu Feb 12 11:34:44 2026 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Feb 12 11:34:44 2026 +0100

    x86/domctl: Conditionalise x86 domctl using DCE rather than ifdef
    
    Make them uniformly return EOPNOTSUPP when their dependent features
    are absent. Otherwise the compiler loses context and they might return
    ENOSYS instead.
    
    debug_op, mem_sharing_op, p2m_audit and psr_alloc change behaviour and
    return EOPNOTSUPP when compiled out, rather than ENOSYS.
    
    While at it, remove the public headers from mem_sharing.h (forward
    declarations are fine) and add a missing xen/sched.h include (for
    complete struct domain definition).
    
    Signed-off-by: Alejandro Vallejo <alejandro.garciavallejo@xxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/domctl.c                  | 33 +++++++++++++++++++--------------
 xen/arch/x86/include/asm/mem_sharing.h | 12 ++++++++----
 xen/arch/x86/include/asm/p2m.h         |  8 ++------
 3 files changed, 29 insertions(+), 24 deletions(-)

diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index d9521808dc..942f41c584 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -220,15 +220,15 @@ long arch_do_domctl(
     {
 
     case XEN_DOMCTL_shadow_op:
-#ifdef CONFIG_PAGING
+        ret = -EOPNOTSUPP;
+        if ( !IS_ENABLED(CONFIG_PAGING) )
+            break;
+
         ret = paging_domctl(d, &domctl->u.shadow_op, u_domctl, 0);
         if ( ret == -ERESTART )
             return hypercall_create_continuation(
                        __HYPERVISOR_paging_domctl_cont, "h", u_domctl);
         copyback = true;
-#else
-        ret = -EOPNOTSUPP;
-#endif
         break;
 
     case XEN_DOMCTL_ioport_permission:
@@ -842,11 +842,14 @@ long arch_do_domctl(
         }
         break;
 
-#ifdef CONFIG_HVM
     case XEN_DOMCTL_debug_op:
     {
         struct vcpu *v;
 
+        ret = -EOPNOTSUPP;
+        if ( !IS_ENABLED(CONFIG_HVM) )
+            break;
+
         ret = -EINVAL;
         if ( (domctl->u.debug_op.vcpu >= d->max_vcpus) ||
              ((v = d->vcpu[domctl->u.debug_op.vcpu]) == NULL) )
@@ -860,7 +863,6 @@ long arch_do_domctl(
         ret = hvm_debug_op(v, domctl->u.debug_op.op);
         break;
     }
-#endif
 
     case XEN_DOMCTL_gdbsx_guestmemio:
     case XEN_DOMCTL_gdbsx_pausevcpu:
@@ -1033,15 +1035,18 @@ long arch_do_domctl(
         break;
     }
 
-#ifdef CONFIG_MEM_SHARING
     case XEN_DOMCTL_mem_sharing_op:
+        ret = -EOPNOTSUPP;
+        if ( !IS_ENABLED(CONFIG_MEM_SHARING) )
+            break;
+
         ret = mem_sharing_domctl(d, &domctl->u.mem_sharing_op);
         break;
-#endif
 
-#if P2M_AUDIT
     case XEN_DOMCTL_audit_p2m:
-        if ( d == currd )
+        if ( !P2M_AUDIT )
+            ret = -EOPNOTSUPP;
+        else if ( d == currd )
             ret = -EPERM;
         else
         {
@@ -1052,7 +1057,6 @@ long arch_do_domctl(
             copyback = true;
         }
         break;
-#endif /* P2M_AUDIT */
 
     case XEN_DOMCTL_set_broken_page_p2m:
     {
@@ -1240,9 +1244,12 @@ long arch_do_domctl(
         break;
 
     case XEN_DOMCTL_psr_alloc:
+        ret = -EOPNOTSUPP;
+        if ( !IS_ENABLED(CONFIG_X86_PSR) )
+            break;
+
         switch ( domctl->u.psr_alloc.cmd )
         {
-#ifdef CONFIG_X86_PSR
         case XEN_DOMCTL_PSR_SET_L3_CBM:
             ret = psr_set_val(d, domctl->u.psr_alloc.target,
                               domctl->u.psr_alloc.data,
@@ -1305,8 +1312,6 @@ long arch_do_domctl(
 
 #undef domctl_psr_get_val
 
-#endif /* CONFIG_X86_PSR */
-
         default:
             ret = -EOPNOTSUPP;
             break;
diff --git a/xen/arch/x86/include/asm/mem_sharing.h 
b/xen/arch/x86/include/asm/mem_sharing.h
index 040962f690..3c67acfa09 100644
--- a/xen/arch/x86/include/asm/mem_sharing.h
+++ b/xen/arch/x86/include/asm/mem_sharing.h
@@ -9,10 +9,12 @@
 #ifndef __MEM_SHARING_H__
 #define __MEM_SHARING_H__
 
-#include <public/domctl.h>
-#include <public/memory.h>
+struct xen_domctl_mem_sharing_op;
 
 #ifdef CONFIG_MEM_SHARING
+#include <xen/sched.h>
+
+struct xen_mem_sharing_op;
 
 #define mem_sharing_enabled(d) ((d)->arch.hvm.mem_sharing.enabled)
 
@@ -92,8 +94,6 @@ int mem_sharing_fork_reset(struct domain *d, bool reset_state,
 int mem_sharing_notify_enomem(struct domain *d, unsigned long gfn,
                               bool allow_sleep);
 int mem_sharing_memop(XEN_GUEST_HANDLE_PARAM(xen_mem_sharing_op_t) arg);
-int mem_sharing_domctl(struct domain *d,
-                       struct xen_domctl_mem_sharing_op *mec);
 
 /*
  * Scans the p2m and relinquishes any shared pages, destroying
@@ -103,6 +103,7 @@ int mem_sharing_domctl(struct domain *d,
 int relinquish_shared_pages(struct domain *d);
 
 #else
+struct domain;
 
 #define mem_sharing_enabled(d) false
 
@@ -147,4 +148,7 @@ static inline int mem_sharing_fork_reset(struct domain *d, 
bool reset_state,
 
 #endif
 
+int mem_sharing_domctl(struct domain *d,
+                       struct xen_domctl_mem_sharing_op *mec);
+
 #endif /* __MEM_SHARING_H__ */
diff --git a/xen/arch/x86/include/asm/p2m.h b/xen/arch/x86/include/asm/p2m.h
index 9016e88411..ef6b02ff0b 100644
--- a/xen/arch/x86/include/asm/p2m.h
+++ b/xen/arch/x86/include/asm/p2m.h
@@ -806,12 +806,8 @@ static inline void p2m_pt_init(struct p2m_domain *p2m) {}
 void *map_domain_gfn(struct p2m_domain *p2m, gfn_t gfn, mfn_t *mfn,
                      p2m_query_t q, uint32_t *pfec);
 
-#if P2M_AUDIT
-extern void audit_p2m(struct domain *d,
-                      uint64_t *orphans,
-                      uint64_t *m2p_bad,
-                      uint64_t *p2m_bad);
-#endif /* P2M_AUDIT */
+void audit_p2m(struct domain *d, uint64_t *orphans,
+               uint64_t *m2p_bad, uint64_t *p2m_bad);
 
 /* Printouts */
 #define P2M_PRINTK(f, a...)                                \
--
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