x86/paravirt: Use common code for paravirt_steal_clock()

Remove the arch-specific variant of paravirt_steal_clock() and use
the common one instead.

With all archs supporting Xen now having been switched to the common
variant, including paravirt.h can be dropped from drivers/xen/time.c.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260105110520.21356-12-jgross@suse.com

Author: jgross1

arch/x86/Kconfig

@@ -799,6 +799,7 @@ if HYPERVISOR_GUEST
 config PARAVIRT
 	bool "Enable paravirtualization code"
 	depends on HAVE_STATIC_CALL
+	select HAVE_PV_STEAL_CLOCK_GEN
 	help
 	  This changes the kernel so it can modify itself when it is run
 	  under a hypervisor, potentially improving performance significantly

arch/x86/include/asm/paravirt.h

@@ -17,10 +17,8 @@
 #include <linux/static_call_types.h>
 #include <asm/frame.h>
 
-u64 dummy_steal_clock(int cpu);
 u64 dummy_sched_clock(void);
 
-DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
 DECLARE_STATIC_CALL(pv_sched_clock, dummy_sched_clock);
 
 void paravirt_set_sched_clock(u64 (*func)(void));
@@ -35,11 +33,6 @@ bool pv_is_native_spin_unlock(void);
 __visible bool __native_vcpu_is_preempted(long cpu);
 bool pv_is_native_vcpu_is_preempted(void);
 
-static inline u64 paravirt_steal_clock(int cpu)
-{
-	return static_call(pv_steal_clock)(cpu);
-}
-
 #ifdef CONFIG_PARAVIRT_SPINLOCKS
 void __init paravirt_set_cap(void);
 #endif

arch/x86/kernel/paravirt.c

@@ -60,12 +60,6 @@ void __init native_pv_lock_init(void)
 		static_branch_enable(&virt_spin_lock_key);
 }
 
-static u64 native_steal_clock(int cpu)
-{
-	return 0;
-}
-
-DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock);
 DEFINE_STATIC_CALL(pv_sched_clock, native_sched_clock);
 
 void paravirt_set_sched_clock(u64 (*func)(void))

arch/x86/xen/time.c

@@ -16,6 +16,7 @@
 #include <linux/slab.h>
 #include <linux/pvclock_gtod.h>
 #include <linux/timekeeper_internal.h>
+#include <linux/sched/cputime.h>
 
 #include <asm/pvclock.h>
 #include <asm/xen/hypervisor.h>

drivers/xen/time.c

@@ -10,9 +10,6 @@
 #include <linux/static_call.h>
 #include <linux/sched/cputime.h>
 
-#ifndef CONFIG_HAVE_PV_STEAL_CLOCK_GEN
-#include <asm/paravirt.h>
-#endif
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>