subject:"\[PATCH v2 05\/21\] arm64\: KVM\: Implement timer save\/restore"

Re: [PATCH v2 05/21] arm64: KVM: Implement timer save/restore

2015-12-01 Thread Marc Zyngier

On 30/11/15 19:59, Christoffer Dall wrote:
> On Fri, Nov 27, 2015 at 06:49:59PM +, Marc Zyngier wrote:
>> Implement the timer save restore as a direct translation of
>> the assembly code version.
>>
>> Signed-off-by: Marc Zyngier 
>> ---
>>  arch/arm64/kvm/hyp/Makefile  |  1 +
>>  arch/arm64/kvm/hyp/hyp.h |  3 ++
>>  arch/arm64/kvm/hyp/timer-sr.c| 71 
>> 
>>  include/clocksource/arm_arch_timer.h |  6 +++
>>  4 files changed, 81 insertions(+)
>>  create mode 100644 arch/arm64/kvm/hyp/timer-sr.c
>>
>> diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
>> index d1e38ce..455dc0a 100644
>> --- a/arch/arm64/kvm/hyp/Makefile
>> +++ b/arch/arm64/kvm/hyp/Makefile
>> @@ -4,3 +4,4 @@
>>  
>>  obj-$(CONFIG_KVM_ARM_HOST) += vgic-v2-sr.o
>>  obj-$(CONFIG_KVM_ARM_HOST) += vgic-v3-sr.o
>> +obj-$(CONFIG_KVM_ARM_HOST) += timer-sr.o
>> diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h
>> index a31cb6e..86aa5a2 100644
>> --- a/arch/arm64/kvm/hyp/hyp.h
>> +++ b/arch/arm64/kvm/hyp/hyp.h
>> @@ -33,5 +33,8 @@ void __vgic_v2_restore_state(struct kvm_vcpu *vcpu);
>>  void __vgic_v3_save_state(struct kvm_vcpu *vcpu);
>>  void __vgic_v3_restore_state(struct kvm_vcpu *vcpu);
>>  
>> +void __timer_save_state(struct kvm_vcpu *vcpu);
>> +void __timer_restore_state(struct kvm_vcpu *vcpu);
>> +
>>  #endif /* __ARM64_KVM_HYP_H__ */
>>  
>> diff --git a/arch/arm64/kvm/hyp/timer-sr.c b/arch/arm64/kvm/hyp/timer-sr.c
>> new file mode 100644
>> index 000..8e2209c
>> --- /dev/null
>> +++ b/arch/arm64/kvm/hyp/timer-sr.c
>> @@ -0,0 +1,71 @@
>> +/*
>> + * Copyright (C) 2012-2015 - ARM Ltd
>> + * Author: Marc Zyngier 
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program.  If not, see .
>> + */
>> +
>> +#include 
>> +#include 
>> +#include 
>> +
>> +#include 
>> +
>> +#include "hyp.h"
>> +
>> +/* vcpu is already in the HYP VA space */
>> +void __hyp_text __timer_save_state(struct kvm_vcpu *vcpu)
>> +{
>> +struct kvm *kvm = kern_hyp_va(vcpu->kvm);
>> +struct arch_timer_cpu *timer = >arch.timer_cpu;
>> +
>> +if (kvm->arch.timer.enabled) {
>> +timer->cntv_ctl = read_sysreg(cntv_ctl_el0);
>> +isb();
>> +timer->cntv_cval = read_sysreg(cntv_cval_el0);
>> +}
>> +
>> +/* Disable the virtual timer */
>> +write_sysreg(0, cntv_ctl_el0);
>> +
>> +/* Allow physical timer/counter access for the host */
>> +write_sysreg((read_sysreg(cnthctl_el2) | CNTHCTL_EL1PCTEN |
>> +  CNTHCTL_EL1PCEN),
>> + cnthctl_el2);
> 
> nit: again I probably prefer reading cnthctl_el2 into a variable, modify
> the bits and write it back, but it's no big deal.

Sure.

>> +
>> +/* Clear cntvoff for the host */
>> +write_sysreg(0, cntvoff_el2);
> 
> why do we do this when we've just disabled the timer?

Because the host does use CNTVCT_EL0 (see the VDSO code), and you don't
want time to go backward over there...

>> +}
>> +
>> +void __hyp_text __timer_restore_state(struct kvm_vcpu *vcpu)
>> +{
>> +struct kvm *kvm = kern_hyp_va(vcpu->kvm);
>> +struct arch_timer_cpu *timer = >arch.timer_cpu;
>> +u64 val;
>> +
>> +/*
>> + * Disallow physical timer access for the guest
>> + * Physical counter access is allowed
>> + */
>> +val = read_sysreg(cnthctl_el2);
>> +val &= ~CNTHCTL_EL1PCEN;
>> +val |= CNTHCTL_EL1PCTEN;
>> +write_sysreg(val, cnthctl_el2);
>> +
>> +if (kvm->arch.timer.enabled) {
>> +write_sysreg(kvm->arch.timer.cntvoff, cntvoff_el2);
>> +write_sysreg(timer->cntv_cval, cntv_cval_el0);
>> +isb();
>> +write_sysreg(timer->cntv_ctl, cntv_ctl_el0);
>> +}
>> +}
>> diff --git a/include/clocksource/arm_arch_timer.h 
>> b/include/clocksource/arm_arch_timer.h
>> index 9916d0e..25d0914 100644
>> --- a/include/clocksource/arm_arch_timer.h
>> +++ b/include/clocksource/arm_arch_timer.h
>> @@ -23,6 +23,12 @@
>>  #define ARCH_TIMER_CTRL_IT_MASK (1 << 1)
>>  #define ARCH_TIMER_CTRL_IT_STAT (1 << 2)
>>  
>> +#define CNTHCTL_EL1PCTEN(1 << 0)
>> +#define CNTHCTL_EL1PCEN (1 << 1)
>> +#define CNTHCTL_EVNTEN  (1 << 2)
>> +#define CNTHCTL_EVNTDIR (1 << 3)
>> +#define CNTHCTL_EVNTI   (0xF << 4)
>>

Re: [PATCH v2 05/21] arm64: KVM: Implement timer save/restore

2015-11-30 Thread Christoffer Dall

On Fri, Nov 27, 2015 at 06:49:59PM +, Marc Zyngier wrote:
> Implement the timer save restore as a direct translation of
> the assembly code version.
> 
> Signed-off-by: Marc Zyngier 
> ---
>  arch/arm64/kvm/hyp/Makefile  |  1 +
>  arch/arm64/kvm/hyp/hyp.h |  3 ++
>  arch/arm64/kvm/hyp/timer-sr.c| 71 
> 
>  include/clocksource/arm_arch_timer.h |  6 +++
>  4 files changed, 81 insertions(+)
>  create mode 100644 arch/arm64/kvm/hyp/timer-sr.c
> 
> diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
> index d1e38ce..455dc0a 100644
> --- a/arch/arm64/kvm/hyp/Makefile
> +++ b/arch/arm64/kvm/hyp/Makefile
> @@ -4,3 +4,4 @@
>  
>  obj-$(CONFIG_KVM_ARM_HOST) += vgic-v2-sr.o
>  obj-$(CONFIG_KVM_ARM_HOST) += vgic-v3-sr.o
> +obj-$(CONFIG_KVM_ARM_HOST) += timer-sr.o
> diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h
> index a31cb6e..86aa5a2 100644
> --- a/arch/arm64/kvm/hyp/hyp.h
> +++ b/arch/arm64/kvm/hyp/hyp.h
> @@ -33,5 +33,8 @@ void __vgic_v2_restore_state(struct kvm_vcpu *vcpu);
>  void __vgic_v3_save_state(struct kvm_vcpu *vcpu);
>  void __vgic_v3_restore_state(struct kvm_vcpu *vcpu);
>  
> +void __timer_save_state(struct kvm_vcpu *vcpu);
> +void __timer_restore_state(struct kvm_vcpu *vcpu);
> +
>  #endif /* __ARM64_KVM_HYP_H__ */
>  
> diff --git a/arch/arm64/kvm/hyp/timer-sr.c b/arch/arm64/kvm/hyp/timer-sr.c
> new file mode 100644
> index 000..8e2209c
> --- /dev/null
> +++ b/arch/arm64/kvm/hyp/timer-sr.c
> @@ -0,0 +1,71 @@
> +/*
> + * Copyright (C) 2012-2015 - ARM Ltd
> + * Author: Marc Zyngier 
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see .
> + */
> +
> +#include 
> +#include 
> +#include 
> +
> +#include 
> +
> +#include "hyp.h"
> +
> +/* vcpu is already in the HYP VA space */
> +void __hyp_text __timer_save_state(struct kvm_vcpu *vcpu)
> +{
> + struct kvm *kvm = kern_hyp_va(vcpu->kvm);
> + struct arch_timer_cpu *timer = >arch.timer_cpu;
> +
> + if (kvm->arch.timer.enabled) {
> + timer->cntv_ctl = read_sysreg(cntv_ctl_el0);
> + isb();
> + timer->cntv_cval = read_sysreg(cntv_cval_el0);
> + }
> +
> + /* Disable the virtual timer */
> + write_sysreg(0, cntv_ctl_el0);
> +
> + /* Allow physical timer/counter access for the host */
> + write_sysreg((read_sysreg(cnthctl_el2) | CNTHCTL_EL1PCTEN |
> +   CNTHCTL_EL1PCEN),
> +  cnthctl_el2);

nit: again I probably prefer reading cnthctl_el2 into a variable, modify
the bits and write it back, but it's no big deal.

> +
> + /* Clear cntvoff for the host */
> + write_sysreg(0, cntvoff_el2);

why do we do this when we've just disabled the timer?

> +}
> +
> +void __hyp_text __timer_restore_state(struct kvm_vcpu *vcpu)
> +{
> + struct kvm *kvm = kern_hyp_va(vcpu->kvm);
> + struct arch_timer_cpu *timer = >arch.timer_cpu;
> + u64 val;
> +
> + /*
> +  * Disallow physical timer access for the guest
> +  * Physical counter access is allowed
> +  */
> + val = read_sysreg(cnthctl_el2);
> + val &= ~CNTHCTL_EL1PCEN;
> + val |= CNTHCTL_EL1PCTEN;
> + write_sysreg(val, cnthctl_el2);
> +
> + if (kvm->arch.timer.enabled) {
> + write_sysreg(kvm->arch.timer.cntvoff, cntvoff_el2);
> + write_sysreg(timer->cntv_cval, cntv_cval_el0);
> + isb();
> + write_sysreg(timer->cntv_ctl, cntv_ctl_el0);
> + }
> +}
> diff --git a/include/clocksource/arm_arch_timer.h 
> b/include/clocksource/arm_arch_timer.h
> index 9916d0e..25d0914 100644
> --- a/include/clocksource/arm_arch_timer.h
> +++ b/include/clocksource/arm_arch_timer.h
> @@ -23,6 +23,12 @@
>  #define ARCH_TIMER_CTRL_IT_MASK  (1 << 1)
>  #define ARCH_TIMER_CTRL_IT_STAT  (1 << 2)
>  
> +#define CNTHCTL_EL1PCTEN (1 << 0)
> +#define CNTHCTL_EL1PCEN  (1 << 1)
> +#define CNTHCTL_EVNTEN   (1 << 2)
> +#define CNTHCTL_EVNTDIR  (1 << 3)
> +#define CNTHCTL_EVNTI(0xF << 4)
> +
>  enum arch_timer_reg {
>   ARCH_TIMER_REG_CTRL,
>   ARCH_TIMER_REG_TVAL,
> -- 
> 2.1.4
> 

Otherwise this looks good.

-Christoffer
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[PATCH v2 05/21] arm64: KVM: Implement timer save/restore

2015-11-27 Thread Marc Zyngier

Implement the timer save restore as a direct translation of
the assembly code version.

Signed-off-by: Marc Zyngier 
---
 arch/arm64/kvm/hyp/Makefile  |  1 +
 arch/arm64/kvm/hyp/hyp.h |  3 ++
 arch/arm64/kvm/hyp/timer-sr.c| 71 
 include/clocksource/arm_arch_timer.h |  6 +++
 4 files changed, 81 insertions(+)
 create mode 100644 arch/arm64/kvm/hyp/timer-sr.c

diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
index d1e38ce..455dc0a 100644
--- a/arch/arm64/kvm/hyp/Makefile
+++ b/arch/arm64/kvm/hyp/Makefile
@@ -4,3 +4,4 @@
 
 obj-$(CONFIG_KVM_ARM_HOST) += vgic-v2-sr.o
 obj-$(CONFIG_KVM_ARM_HOST) += vgic-v3-sr.o
+obj-$(CONFIG_KVM_ARM_HOST) += timer-sr.o
diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h
index a31cb6e..86aa5a2 100644
--- a/arch/arm64/kvm/hyp/hyp.h
+++ b/arch/arm64/kvm/hyp/hyp.h
@@ -33,5 +33,8 @@ void __vgic_v2_restore_state(struct kvm_vcpu *vcpu);
 void __vgic_v3_save_state(struct kvm_vcpu *vcpu);
 void __vgic_v3_restore_state(struct kvm_vcpu *vcpu);
 
+void __timer_save_state(struct kvm_vcpu *vcpu);
+void __timer_restore_state(struct kvm_vcpu *vcpu);
+
 #endif /* __ARM64_KVM_HYP_H__ */
 
diff --git a/arch/arm64/kvm/hyp/timer-sr.c b/arch/arm64/kvm/hyp/timer-sr.c
new file mode 100644
index 000..8e2209c
--- /dev/null
+++ b/arch/arm64/kvm/hyp/timer-sr.c
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2012-2015 - ARM Ltd
+ * Author: Marc Zyngier 
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see .
+ */
+
+#include 
+#include 
+#include 
+
+#include 
+
+#include "hyp.h"
+
+/* vcpu is already in the HYP VA space */
+void __hyp_text __timer_save_state(struct kvm_vcpu *vcpu)
+{
+   struct kvm *kvm = kern_hyp_va(vcpu->kvm);
+   struct arch_timer_cpu *timer = >arch.timer_cpu;
+
+   if (kvm->arch.timer.enabled) {
+   timer->cntv_ctl = read_sysreg(cntv_ctl_el0);
+   isb();
+   timer->cntv_cval = read_sysreg(cntv_cval_el0);
+   }
+
+   /* Disable the virtual timer */
+   write_sysreg(0, cntv_ctl_el0);
+
+   /* Allow physical timer/counter access for the host */
+   write_sysreg((read_sysreg(cnthctl_el2) | CNTHCTL_EL1PCTEN |
+ CNTHCTL_EL1PCEN),
+cnthctl_el2);
+
+   /* Clear cntvoff for the host */
+   write_sysreg(0, cntvoff_el2);
+}
+
+void __hyp_text __timer_restore_state(struct kvm_vcpu *vcpu)
+{
+   struct kvm *kvm = kern_hyp_va(vcpu->kvm);
+   struct arch_timer_cpu *timer = >arch.timer_cpu;
+   u64 val;
+
+   /*
+* Disallow physical timer access for the guest
+* Physical counter access is allowed
+*/
+   val = read_sysreg(cnthctl_el2);
+   val &= ~CNTHCTL_EL1PCEN;
+   val |= CNTHCTL_EL1PCTEN;
+   write_sysreg(val, cnthctl_el2);
+
+   if (kvm->arch.timer.enabled) {
+   write_sysreg(kvm->arch.timer.cntvoff, cntvoff_el2);
+   write_sysreg(timer->cntv_cval, cntv_cval_el0);
+   isb();
+   write_sysreg(timer->cntv_ctl, cntv_ctl_el0);
+   }
+}
diff --git a/include/clocksource/arm_arch_timer.h 
b/include/clocksource/arm_arch_timer.h
index 9916d0e..25d0914 100644
--- a/include/clocksource/arm_arch_timer.h
+++ b/include/clocksource/arm_arch_timer.h
@@ -23,6 +23,12 @@
 #define ARCH_TIMER_CTRL_IT_MASK(1 << 1)
 #define ARCH_TIMER_CTRL_IT_STAT(1 << 2)
 
+#define CNTHCTL_EL1PCTEN   (1 << 0)
+#define CNTHCTL_EL1PCEN(1 << 1)
+#define CNTHCTL_EVNTEN (1 << 2)
+#define CNTHCTL_EVNTDIR(1 << 3)
+#define CNTHCTL_EVNTI  (0xF << 4)
+
 enum arch_timer_reg {
ARCH_TIMER_REG_CTRL,
ARCH_TIMER_REG_TVAL,
-- 
2.1.4

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Re: [PATCH v2 05/21] arm64: KVM: Implement timer save/restore

Re: [PATCH v2 05/21] arm64: KVM: Implement timer save/restore

[PATCH v2 05/21] arm64: KVM: Implement timer save/restore

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