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.
This enables to replace the hook with a bool indicating whether native_io_delay() should be called. Signed-off-by: Juergen Gross <[email protected]> --- V3: - rebase to tip/master kernel branch --- arch/x86/include/asm/io.h | 9 ++++++--- arch/x86/include/asm/paravirt-base.h | 6 ++++++ arch/x86/include/asm/paravirt.h | 11 ----------- arch/x86/include/asm/paravirt_types.h | 2 -- arch/x86/kernel/cpu/vmware.c | 2 +- arch/x86/kernel/kvm.c | 8 +------- arch/x86/kernel/paravirt.c | 3 +-- arch/x86/xen/enlighten_pv.c | 6 +----- 8 files changed, 16 insertions(+), 31 deletions(-) diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index ca309a3227c7..8a9292ce7d2d 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -243,11 +243,16 @@ 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(); @@ -256,8 +261,6 @@ static inline void slow_down_io(void) #endif } -#endif - #define BUILDIO(bwl, type) \ static inline void out##bwl##_p(type value, u16 port) \ { \ diff --git a/arch/x86/include/asm/paravirt-base.h b/arch/x86/include/asm/paravirt-base.h index 982a0b93bc76..3b9e7772d196 100644 --- a/arch/x86/include/asm/paravirt-base.h +++ b/arch/x86/include/asm/paravirt-base.h @@ -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 diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index b21072af731d..f4885bd98a18 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -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); diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 7ccd41628d36..3946d0f69921 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -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); diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c index a3e6936839b1..eee0d1a48802 100644 --- a/arch/x86/kernel/cpu/vmware.c +++ b/arch/x86/kernel/cpu/vmware.c @@ -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; diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index de550b12d9ab..8c3221048d9f 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -75,12 +75,6 @@ DEFINE_PER_CPU_DECRYPTED(struct kvm_steal_time, steal_time) __aligned(64) __visi static int has_steal_clock = 0; static int has_guest_poll = 0; -/* - * No need for any "IO delay" on KVM - */ -static void kvm_io_delay(void) -{ -} #define KVM_TASK_SLEEP_HASHBITS 8 #define KVM_TASK_SLEEP_HASHSIZE (1<<KVM_TASK_SLEEP_HASHBITS) @@ -314,7 +308,7 @@ static void __init paravirt_ops_setup(void) pv_info.name = "KVM"; if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY)) - pv_ops.cpu.io_delay = kvm_io_delay; + pv_info.io_delay = false; #ifdef CONFIG_X86_IO_APIC no_timer_check = 1; diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index a6ed52cae003..792fa96b3233 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -94,6 +94,7 @@ struct pv_info pv_info = { #ifdef CONFIG_PARAVIRT_XXL .extra_user_64bit_cs = __USER_CS, #endif + .io_delay = true, }; /* 64-bit pagetable entries */ @@ -101,8 +102,6 @@ struct pv_info pv_info = { struct paravirt_patch_template pv_ops = { /* Cpu ops. */ - .cpu.io_delay = native_io_delay, - #ifdef CONFIG_PARAVIRT_XXL .cpu.cpuid = native_cpuid, .cpu.get_debugreg = pv_native_get_debugreg, diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c index 8a19a88190ee..9c9695f5d158 100644 --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -1046,10 +1046,6 @@ static void xen_update_io_bitmap(void) } #endif -static void xen_io_delay(void) -{ -} - static DEFINE_PER_CPU(unsigned long, xen_cr0_value); static unsigned long xen_read_cr0(void) @@ -1209,6 +1205,7 @@ void __init xen_setup_vcpu_info_placement(void) static const struct pv_info xen_info __initconst = { .extra_user_64bit_cs = FLAT_USER_CS64, + .io_delay = false, .name = "Xen", }; @@ -1392,7 +1389,6 @@ asmlinkage __visible void __init xen_start_kernel(struct start_info *si) pv_ops.cpu.invalidate_io_bitmap = xen_invalidate_io_bitmap; pv_ops.cpu.update_io_bitmap = xen_update_io_bitmap; #endif - pv_ops.cpu.io_delay = xen_io_delay; pv_ops.cpu.start_context_switch = xen_start_context_switch; pv_ops.cpu.end_context_switch = xen_end_context_switch; -- 2.51.0
