Commit 9eece498 authored by Juergen Gross's avatar Juergen Gross Committed by Ingo Molnar
Browse files

x86/paravirt: Replace io_delay() hook with a bool 



The io_delay() paravirt hook is in no way performance critical and all users
setting it to a different function than native_io_delay() are using an empty
function as replacement.

Allow replacing the hook with a bool indicating whether native_io_delay()
should be called.

  [ bp: Massage commit message. ]

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://patch.msgid.link/20260119182632.596369-3-jgross@suse.com
parent 36c1eb95

arch/x86/include/asm/io.h

+6 −3
Original line number Diff line number Diff line
@@ -242,11 +242,16 @@ extern int io_delay_type; 
extern void io_delay_init(void);



#if defined(CONFIG_PARAVIRT)

#include <asm/paravirt.h>

#include <asm/paravirt-base.h>

#else

#define call_io_delay() true

#endif



static inline void slow_down_io(void)

{

	if (!call_io_delay())

		return;



	native_io_delay();

#ifdef REALLY_SLOW_IO

	native_io_delay();
@@ -255,8 +260,6 @@ static inline void slow_down_io(void) 
#endif

}



#endif



#define BUILDIO(bwl, type)						\

static inline void out##bwl##_p(type value, u16 port)			\

{									\

arch/x86/include/asm/paravirt-base.h

+6 −0
Original line number Diff line number Diff line
@@ -15,6 +15,8 @@ struct pv_info { 
#ifdef CONFIG_PARAVIRT_XXL

	u16 extra_user_64bit_cs;  /* __USER_CS if none */

#endif

	bool io_delay;



	const char *name;

};
@@ -26,6 +28,10 @@ u64 _paravirt_ident_64(u64); 
#endif

#define paravirt_nop	((void *)nop_func)



#ifdef CONFIG_PARAVIRT

#define call_io_delay() pv_info.io_delay

#endif



#ifdef CONFIG_PARAVIRT_SPINLOCKS

void paravirt_set_cap(void);

#else

arch/x86/include/asm/paravirt.h

+0 −11
Original line number Diff line number Diff line
@@ -19,17 +19,6 @@ 
#include <linux/cpumask.h>

#include <asm/frame.h>



/* The paravirtualized I/O functions */

static inline void slow_down_io(void)

{

	PVOP_VCALL0(pv_ops, cpu.io_delay);

#ifdef REALLY_SLOW_IO

	PVOP_VCALL0(pv_ops, cpu.io_delay);

	PVOP_VCALL0(pv_ops, cpu.io_delay);

	PVOP_VCALL0(pv_ops, cpu.io_delay);

#endif

}



void native_flush_tlb_local(void);

void native_flush_tlb_global(void);

void native_flush_tlb_one_user(unsigned long addr);

arch/x86/include/asm/paravirt_types.h

+0 −2
Original line number Diff line number Diff line
@@ -30,8 +30,6 @@ struct pv_lazy_ops { 


struct pv_cpu_ops {

	/* hooks for various privileged instructions */

	void (*io_delay)(void);



#ifdef CONFIG_PARAVIRT_XXL

	unsigned long (*get_debugreg)(int regno);

	void (*set_debugreg)(int regno, unsigned long value);

arch/x86/kernel/cpu/vmware.c

+1 −1
Original line number Diff line number Diff line
@@ -339,7 +339,7 @@ arch_initcall(activate_jump_labels); 
static void __init vmware_paravirt_ops_setup(void)

{

	pv_info.name = "VMware hypervisor";

	pv_ops.cpu.io_delay = paravirt_nop;

	pv_info.io_delay = false;



	if (vmware_tsc_khz == 0)

		return;