Re: [PATCH] xen/x86: move domctl.o out of PV_SHIM_EXCLUSIVE

[Stefano Stabellini <stefano.stabellini@xxxxxxx>]

On Tue, 26 Aug 2025, Stefano Stabellini wrote:
> Hi all,
> 
> So I ran a test and the appended change, which is based on [1] and
> renaming CONFIG_DOMCTL to CONFIG_SYSCTL, is sufficient to resolve the
> build issue.
> 
> For 4.21, I suggest we go with two patches:
> 1) global rename of CONFIG_SYSCTL to CONFIG_MGMT_HYPERCALLS
> 2) stub domctl_lock_acquire/release based on CONFIG_MGMT_HYPERCALLS
> 
> Jan, are you OK with this?

The other patch doesn't work in the regular case but this patch does. I
ran it through 60+ randconfigs and so far so good. The strategy is still
the same I suggested above for 4.21: global rename, plus one more patch
(this one).


diff --git a/xen/common/Makefile b/xen/common/Makefile
index c316957fcb..352f004a2c 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -50,7 +50,6 @@ obj-y += spinlock.o
 obj-$(CONFIG_STACK_PROTECTOR) += stack-protector.o
 obj-y += stop_machine.o
 obj-y += symbols.o
-obj-$(CONFIG_SYSCTL) += sysctl.o
 obj-y += tasklet.o
 obj-y += time.o
 obj-y += timer.o
@@ -70,7 +69,10 @@ obj-bin-$(CONFIG_X86) += $(foreach n,decompress bunzip2 unxz 
unlzma lzo unlzo un
 obj-$(CONFIG_COMPAT) += $(addprefix compat/,domain.o memory.o multicall.o 
xlat.o)
 
 ifneq ($(CONFIG_PV_SHIM_EXCLUSIVE),y)
+ifeq ($(CONFIG_SYSCTL),y)
 obj-y += domctl.o
+obj-y += sysctl.o
+endif
 endif
 
 extra-y := symbols-dummy.o
diff --git a/xen/include/hypercall-defs.c b/xen/include/hypercall-defs.c
index 8370b4b289..18ab294f94 100644
--- a/xen/include/hypercall-defs.c
+++ b/xen/include/hypercall-defs.c
@@ -194,14 +194,16 @@ kexec_op(unsigned long op, void *uarg)
 #ifdef CONFIG_IOREQ_SERVER
 dm_op(domid_t domid, unsigned int nr_bufs, xen_dm_op_buf_t *bufs)
 #endif
-#ifdef CONFIG_SYSCTL
+#if !defined(CONFIG_PV_SHIM_EXCLUSIVE) && defined(CONFIG_SYSCTL)
 sysctl(xen_sysctl_t *u_sysctl)
 #endif
 #if defined(CONFIG_X86) && defined(CONFIG_PAGING)
 paging_domctl_cont(xen_domctl_t *u_domctl)
 #endif
 #ifndef CONFIG_PV_SHIM_EXCLUSIVE
+#ifdef CONFIG_SYSCTL
 domctl(xen_domctl_t *u_domctl)
+#endif
 platform_op(xen_platform_op_t *u_xenpf_op)
 #endif
 #ifdef CONFIG_HVM
@@ -277,10 +279,8 @@ physdev_op                         compat   do       hvm   
   hvm      do_arm
 #ifdef CONFIG_HVM
 hvm_op                             do       do       do       do       do
 #endif
-#ifdef CONFIG_SYSCTL
+#if !defined(CONFIG_PV_SHIM_EXCLUSIVE) && defined(CONFIG_SYSCTL)
 sysctl                             do       do       do       do       do
-#endif
-#ifndef CONFIG_PV_SHIM_EXCLUSIVE
 domctl                             do       do       do       do       do
 #endif
 #ifdef CONFIG_KEXEC
diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
index e10baf2615..cb80e49de1 100644
--- a/xen/include/xen/domain.h
+++ b/xen/include/xen/domain.h
@@ -148,8 +148,17 @@ void arch_dump_domain_info(struct domain *d);
 
 int arch_vcpu_reset(struct vcpu *v);
 
+#if !defined(CONFIG_PV_SHIM_EXCLUSIVE) && defined(CONFIG_SYSCTL)
 bool domctl_lock_acquire(void);
 void domctl_lock_release(void);
+#else
+static inline bool domctl_lock_acquire(void)
+{
+    return false;
+}
+
+static inline void domctl_lock_release(void) {}
+#endif /* CONFIG_DOMCTL */
 
 /*
  * Continue the current hypercall via func(data) on specified cpu.
@@ -182,7 +191,7 @@ struct vnuma_info {
     struct xen_vmemrange *vmemrange;
 };
 
-#ifndef CONFIG_PV_SHIM_EXCLUSIVE
+#if !defined(CONFIG_PV_SHIM_EXCLUSIVE) && defined(CONFIG_SYSCTL)
 void vnuma_destroy(struct vnuma_info *vnuma);
 #else
 static inline void vnuma_destroy(struct vnuma_info *vnuma) { ASSERT(!vnuma); }