Re: [RFC PATCH 08/43] powerpc/64s: Keep AMOR SPR a constant ~0 at runtime

2021-06-30 Thread Fabiano Rosas 
Nicholas Piggin  writes:

> This register controls supervisor SPR modifications, and as such is only
> relevant for KVM. KVM always sets AMOR to ~0 on guest entry, and never
> restores it coming back out to the host, so it can be kept constant and
> avoid the mtSPR in KVM guest entry.
>
> -21 cycles (9116) cycles POWER9 virt-mode NULL hcall
>
> Signed-off-by: Nicholas Piggin 

Reviewed-by: Fabiano Rosas 

> ---
>  arch/powerpc/kernel/cpu_setup_power.c|  8 
>  arch/powerpc/kernel/dt_cpu_ftrs.c|  2 ++
>  arch/powerpc/kvm/book3s_hv_p9_entry.c|  2 --
>  arch/powerpc/kvm/book3s_hv_rmhandlers.S  |  2 --
>  arch/powerpc/mm/book3s64/radix_pgtable.c | 15 ---
>  arch/powerpc/platforms/powernv/idle.c|  8 +++-
>  6 files changed, 13 insertions(+), 24 deletions(-)
>
> diff --git a/arch/powerpc/kernel/cpu_setup_power.c 
> b/arch/powerpc/kernel/cpu_setup_power.c
> index 3cca88ee96d7..a29dc8326622 100644
> --- a/arch/powerpc/kernel/cpu_setup_power.c
> +++ b/arch/powerpc/kernel/cpu_setup_power.c
> @@ -137,6 +137,7 @@ void __setup_cpu_power7(unsigned long offset, struct 
> cpu_spec *t)
>   return;
>
>   mtspr(SPRN_LPID, 0);
> + mtspr(SPRN_AMOR, ~0);
>   mtspr(SPRN_PCR, PCR_MASK);
>   init_LPCR_ISA206(mfspr(SPRN_LPCR), LPCR_LPES1 >> LPCR_LPES_SH);
>  }
> @@ -150,6 +151,7 @@ void __restore_cpu_power7(void)
>   return;
>
>   mtspr(SPRN_LPID, 0);
> + mtspr(SPRN_AMOR, ~0);
>   mtspr(SPRN_PCR, PCR_MASK);
>   init_LPCR_ISA206(mfspr(SPRN_LPCR), LPCR_LPES1 >> LPCR_LPES_SH);
>  }
> @@ -164,6 +166,7 @@ void __setup_cpu_power8(unsigned long offset, struct 
> cpu_spec *t)
>   return;
>
>   mtspr(SPRN_LPID, 0);
> + mtspr(SPRN_AMOR, ~0);
>   mtspr(SPRN_PCR, PCR_MASK);
>   init_LPCR_ISA206(mfspr(SPRN_LPCR) | LPCR_PECEDH, 0); /* LPES = 0 */
>   init_HFSCR();
> @@ -184,6 +187,7 @@ void __restore_cpu_power8(void)
>   return;
>
>   mtspr(SPRN_LPID, 0);
> + mtspr(SPRN_AMOR, ~0);
>   mtspr(SPRN_PCR, PCR_MASK);
>   init_LPCR_ISA206(mfspr(SPRN_LPCR) | LPCR_PECEDH, 0); /* LPES = 0 */
>   init_HFSCR();
> @@ -202,6 +206,7 @@ void __setup_cpu_power9(unsigned long offset, struct 
> cpu_spec *t)
>   mtspr(SPRN_PSSCR, 0);
>   mtspr(SPRN_LPID, 0);
>   mtspr(SPRN_PID, 0);
> + mtspr(SPRN_AMOR, ~0);
>   mtspr(SPRN_PCR, PCR_MASK);
>   init_LPCR_ISA300((mfspr(SPRN_LPCR) | LPCR_PECEDH | LPCR_PECE_HVEE |\
>LPCR_HVICE | LPCR_HEIC) & ~(LPCR_UPRT | LPCR_HR), 0);
> @@ -223,6 +228,7 @@ void __restore_cpu_power9(void)
>   mtspr(SPRN_PSSCR, 0);
>   mtspr(SPRN_LPID, 0);
>   mtspr(SPRN_PID, 0);
> + mtspr(SPRN_AMOR, ~0);
>   mtspr(SPRN_PCR, PCR_MASK);
>   init_LPCR_ISA300((mfspr(SPRN_LPCR) | LPCR_PECEDH | LPCR_PECE_HVEE |\
>LPCR_HVICE | LPCR_HEIC) & ~(LPCR_UPRT | LPCR_HR), 0);
> @@ -242,6 +248,7 @@ void __setup_cpu_power10(unsigned long offset, struct 
> cpu_spec *t)
>   mtspr(SPRN_PSSCR, 0);
>   mtspr(SPRN_LPID, 0);
>   mtspr(SPRN_PID, 0);
> + mtspr(SPRN_AMOR, ~0);
>   mtspr(SPRN_PCR, PCR_MASK);
>   init_LPCR_ISA300((mfspr(SPRN_LPCR) | LPCR_PECEDH | LPCR_PECE_HVEE |\
>LPCR_HVICE | LPCR_HEIC) & ~(LPCR_UPRT | LPCR_HR), 0);
> @@ -264,6 +271,7 @@ void __restore_cpu_power10(void)
>   mtspr(SPRN_PSSCR, 0);
>   mtspr(SPRN_LPID, 0);
>   mtspr(SPRN_PID, 0);
> + mtspr(SPRN_AMOR, ~0);
>   mtspr(SPRN_PCR, PCR_MASK);
>   init_LPCR_ISA300((mfspr(SPRN_LPCR) | LPCR_PECEDH | LPCR_PECE_HVEE |\
>LPCR_HVICE | LPCR_HEIC) & ~(LPCR_UPRT | LPCR_HR), 0);
> diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c 
> b/arch/powerpc/kernel/dt_cpu_ftrs.c
> index 358aee7c2d79..0a6b36b4bda8 100644
> --- a/arch/powerpc/kernel/dt_cpu_ftrs.c
> +++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
> @@ -80,6 +80,7 @@ static void __restore_cpu_cpufeatures(void)
>   mtspr(SPRN_LPCR, system_registers.lpcr);
>   if (hv_mode) {
>   mtspr(SPRN_LPID, 0);
> + mtspr(SPRN_AMOR, ~0);
>   mtspr(SPRN_HFSCR, system_registers.hfscr);
>   mtspr(SPRN_PCR, system_registers.pcr);
>   }
> @@ -216,6 +217,7 @@ static int __init feat_enable_hv(struct dt_cpu_feature *f)
>   }
>
>   mtspr(SPRN_LPID, 0);
> + mtspr(SPRN_AMOR, ~0);
>
>   lpcr = mfspr(SPRN_LPCR);
>   lpcr &=  ~LPCR_LPES0; /* HV external interrupts */
> diff --git a/arch/powerpc/kvm/book3s_hv_p9_entry.c 
> b/arch/powerpc/kvm/book3s_hv_p9_entry.c
> index c4f3e066fcb4..a3281f0c9214 100644
> --- a/arch/powerpc/kvm/book3s_hv_p9_entry.c
> +++ b/arch/powerpc/kvm/book3s_hv_p9_entry.c
> @@ -286,8 +286,6 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 
> time_limit, unsigned long lpc
>   mtspr(SPRN_SPRG2, vcpu->arch.shregs.sprg2);
>   mtspr(SPRN_SPRG3, vcpu->arch.shregs.sprg3);
>
> - mtspr(SPRN_AMOR, ~0UL);
> -
>   local_paca->kvm_hstate.in_guest =

[RFC PATCH 08/43] powerpc/64s: Keep AMOR SPR a constant ~0 at runtime

2021-06-22 Thread Nicholas Piggin 
This register controls supervisor SPR modifications, and as such is only
relevant for KVM. KVM always sets AMOR to ~0 on guest entry, and never
restores it coming back out to the host, so it can be kept constant and
avoid the mtSPR in KVM guest entry.

-21 cycles (9116) cycles POWER9 virt-mode NULL hcall

Signed-off-by: Nicholas Piggin 
---
 arch/powerpc/kernel/cpu_setup_power.c|  8 
 arch/powerpc/kernel/dt_cpu_ftrs.c|  2 ++
 arch/powerpc/kvm/book3s_hv_p9_entry.c|  2 --
 arch/powerpc/kvm/book3s_hv_rmhandlers.S  |  2 --
 arch/powerpc/mm/book3s64/radix_pgtable.c | 15 ---
 arch/powerpc/platforms/powernv/idle.c|  8 +++-
 6 files changed, 13 insertions(+), 24 deletions(-)

diff --git a/arch/powerpc/kernel/cpu_setup_power.c 
b/arch/powerpc/kernel/cpu_setup_power.c
index 3cca88ee96d7..a29dc8326622 100644
--- a/arch/powerpc/kernel/cpu_setup_power.c
+++ b/arch/powerpc/kernel/cpu_setup_power.c
@@ -137,6 +137,7 @@ void __setup_cpu_power7(unsigned long offset, struct 
cpu_spec *t)
return;
 
mtspr(SPRN_LPID, 0);
+   mtspr(SPRN_AMOR, ~0);
mtspr(SPRN_PCR, PCR_MASK);
init_LPCR_ISA206(mfspr(SPRN_LPCR), LPCR_LPES1 >> LPCR_LPES_SH);
 }
@@ -150,6 +151,7 @@ void __restore_cpu_power7(void)
return;
 
mtspr(SPRN_LPID, 0);
+   mtspr(SPRN_AMOR, ~0);
mtspr(SPRN_PCR, PCR_MASK);
init_LPCR_ISA206(mfspr(SPRN_LPCR), LPCR_LPES1 >> LPCR_LPES_SH);
 }
@@ -164,6 +166,7 @@ void __setup_cpu_power8(unsigned long offset, struct 
cpu_spec *t)
return;
 
mtspr(SPRN_LPID, 0);
+   mtspr(SPRN_AMOR, ~0);
mtspr(SPRN_PCR, PCR_MASK);
init_LPCR_ISA206(mfspr(SPRN_LPCR) | LPCR_PECEDH, 0); /* LPES = 0 */
init_HFSCR();
@@ -184,6 +187,7 @@ void __restore_cpu_power8(void)
return;
 
mtspr(SPRN_LPID, 0);
+   mtspr(SPRN_AMOR, ~0);
mtspr(SPRN_PCR, PCR_MASK);
init_LPCR_ISA206(mfspr(SPRN_LPCR) | LPCR_PECEDH, 0); /* LPES = 0 */
init_HFSCR();
@@ -202,6 +206,7 @@ void __setup_cpu_power9(unsigned long offset, struct 
cpu_spec *t)
mtspr(SPRN_PSSCR, 0);
mtspr(SPRN_LPID, 0);
mtspr(SPRN_PID, 0);
+   mtspr(SPRN_AMOR, ~0);
mtspr(SPRN_PCR, PCR_MASK);
init_LPCR_ISA300((mfspr(SPRN_LPCR) | LPCR_PECEDH | LPCR_PECE_HVEE |\
 LPCR_HVICE | LPCR_HEIC) & ~(LPCR_UPRT | LPCR_HR), 0);
@@ -223,6 +228,7 @@ void __restore_cpu_power9(void)
mtspr(SPRN_PSSCR, 0);
mtspr(SPRN_LPID, 0);
mtspr(SPRN_PID, 0);
+   mtspr(SPRN_AMOR, ~0);
mtspr(SPRN_PCR, PCR_MASK);
init_LPCR_ISA300((mfspr(SPRN_LPCR) | LPCR_PECEDH | LPCR_PECE_HVEE |\
 LPCR_HVICE | LPCR_HEIC) & ~(LPCR_UPRT | LPCR_HR), 0);
@@ -242,6 +248,7 @@ void __setup_cpu_power10(unsigned long offset, struct 
cpu_spec *t)
mtspr(SPRN_PSSCR, 0);
mtspr(SPRN_LPID, 0);
mtspr(SPRN_PID, 0);
+   mtspr(SPRN_AMOR, ~0);
mtspr(SPRN_PCR, PCR_MASK);
init_LPCR_ISA300((mfspr(SPRN_LPCR) | LPCR_PECEDH | LPCR_PECE_HVEE |\
 LPCR_HVICE | LPCR_HEIC) & ~(LPCR_UPRT | LPCR_HR), 0);
@@ -264,6 +271,7 @@ void __restore_cpu_power10(void)
mtspr(SPRN_PSSCR, 0);
mtspr(SPRN_LPID, 0);
mtspr(SPRN_PID, 0);
+   mtspr(SPRN_AMOR, ~0);
mtspr(SPRN_PCR, PCR_MASK);
init_LPCR_ISA300((mfspr(SPRN_LPCR) | LPCR_PECEDH | LPCR_PECE_HVEE |\
 LPCR_HVICE | LPCR_HEIC) & ~(LPCR_UPRT | LPCR_HR), 0);
diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c 
b/arch/powerpc/kernel/dt_cpu_ftrs.c
index 358aee7c2d79..0a6b36b4bda8 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -80,6 +80,7 @@ static void __restore_cpu_cpufeatures(void)
mtspr(SPRN_LPCR, system_registers.lpcr);
if (hv_mode) {
mtspr(SPRN_LPID, 0);
+   mtspr(SPRN_AMOR, ~0);
mtspr(SPRN_HFSCR, system_registers.hfscr);
mtspr(SPRN_PCR, system_registers.pcr);
}
@@ -216,6 +217,7 @@ static int __init feat_enable_hv(struct dt_cpu_feature *f)
}
 
mtspr(SPRN_LPID, 0);
+   mtspr(SPRN_AMOR, ~0);
 
lpcr = mfspr(SPRN_LPCR);
lpcr &=  ~LPCR_LPES0; /* HV external interrupts */
diff --git a/arch/powerpc/kvm/book3s_hv_p9_entry.c 
b/arch/powerpc/kvm/book3s_hv_p9_entry.c
index c4f3e066fcb4..a3281f0c9214 100644
--- a/arch/powerpc/kvm/book3s_hv_p9_entry.c
+++ b/arch/powerpc/kvm/book3s_hv_p9_entry.c
@@ -286,8 +286,6 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 
time_limit, unsigned long lpc
mtspr(SPRN_SPRG2, vcpu->arch.shregs.sprg2);
mtspr(SPRN_SPRG3, vcpu->arch.shregs.sprg3);
 
-   mtspr(SPRN_AMOR, ~0UL);
-
local_paca->kvm_hstate.in_guest = KVM_GUEST_MODE_HV_P9;
 
/*
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S 
b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index