[PATCH] ARM: KVM: Allow host virt timer irq to be different from guest timer virt irq
Anup Patel
anup at brainfault.org
Sat Apr 27 08:19:31 EDT 2013
On Sat, Apr 27, 2013 at 2:49 PM, Marc Zyngier <marc.zyngier at arm.com> wrote:
> On Sat, 27 Apr 2013 13:38:06 +0530, Anup Patel <anup.patel at linaro.org>
> wrote:
>> The arch_timer irq numbers (or PPI numbers) are implementation dependent
>> so, the host virtual timer irq number can be different from guest
> virtual
>> timer irq number.
>>
>> This patch ensures that host virtual timer irq number is read from DTB
> and
>> guest virtual timer irq is determined based on vcpu target type.
>
> Christoffer already commented on the width of your commit message.
> It doesn't show here as my stupid email client reformats it aumatically,
> but you may want to check in the archive:
>
> https://lists.cs.columbia.edu/pipermail/kvmarm/2013-April/005616.html
>
> Please make sure you insert newlines around position 70. Or use a half
> decent editor.
Ok, will do.
>
>> Signed-off-by: Anup Patel <anup.patel at linaro.org>
>> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar at linaro.org>
>> ---
>> arch/arm/include/asm/kvm_arch_timer.h | 9 +++++++++
>> arch/arm/kvm/arch_timer.c | 35
>> ++++++++++++++++++++++++++-------
>> arch/arm/kvm/reset.c | 11 ++++++++++-
>> 3 files changed, 47 insertions(+), 8 deletions(-)
>>
>> diff --git a/arch/arm/include/asm/kvm_arch_timer.h
>> b/arch/arm/include/asm/kvm_arch_timer.h
>> index 68cb9e1..51b0316 100644
>> --- a/arch/arm/include/asm/kvm_arch_timer.h
>> +++ b/arch/arm/include/asm/kvm_arch_timer.h
>> @@ -61,6 +61,8 @@ struct arch_timer_cpu {
>> #ifdef CONFIG_KVM_ARM_TIMER
>> int kvm_timer_hyp_init(void);
>> int kvm_timer_init(struct kvm *kvm);
>> +int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu,
>> + const struct kvm_irq_level *irq);
>> void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu);
>> void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu);
>> void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu);
>> @@ -76,7 +78,14 @@ static inline int kvm_timer_init(struct kvm *kvm)
>> return 0;
>> }
>>
>> +int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu,
>> + const struct kvm_irq_level *irq)
>
> static inline, please. This is an include file...
This one is accidental. I had it static inlined.
>
>> +{
>> + return 0;
>> +}
>> +
>> static inline void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu) {}
>> +
>> static inline void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu) {}
>> static inline void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu) {}
>> static inline void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu) {}
>> diff --git a/arch/arm/kvm/arch_timer.c b/arch/arm/kvm/arch_timer.c
>> index 49a7516..c07b63c 100644
>> --- a/arch/arm/kvm/arch_timer.c
>> +++ b/arch/arm/kvm/arch_timer.c
>> @@ -30,7 +30,7 @@
>>
>> static struct timecounter *timecounter;
>> static struct workqueue_struct *wqueue;
>> -static struct kvm_irq_level timer_irq = {
>> +static struct kvm_irq_level host_timer_irq = {
>> .level = 1,
>> };
>>
>> @@ -67,8 +67,8 @@ static void kvm_timer_inject_irq(struct kvm_vcpu
> *vcpu)
>>
>> timer->cntv_ctl |= ARCH_TIMER_CTRL_IT_MASK;
>> kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
>> - vcpu->arch.timer_cpu.irq->irq,
>> - vcpu->arch.timer_cpu.irq->level);
>> + timer->irq->irq,
>> + timer->irq->level);
>> }
>>
>> static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id)
>> @@ -156,6 +156,27 @@ void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu)
>> timer_arm(timer, ns);
>> }
>>
>> +int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu,
>> + const struct kvm_irq_level *irq)
>> +{
>> + struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
>> +
>> + /*
>> + * The vcpu timer irq number cannot be determined in
>> + * kvm_timer_vcpu_init() because it is called much before
>> + * kvm_vcpu_set_target(). To handle this, we determine
>> + * vcpu timer irq number when the vcpu is resetted.
>> + */
>> + timer->irq = irq;
>> +
>> + /*
>> + * Make sure timer is disarmed.
>> + */
>> + timer_disarm(timer);
>
> What is that for? Timer has not been started yet, for the lack of an IRQ.
> Actually, the vcpu has never ran. Why would you need to disarm it?
This is in case a vcpu is resetted at runtime from user space or psci.
Also, since we have named it timer_vcpu_reset(), it made sense to
atleast disarm the timer.
>
>> + return 0;
>
> If this function has no failure case, it can return void.
Ok, will make it return void.
>
>> +}
>> +
>> void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
>> {
>> struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
>> @@ -163,12 +184,12 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
>> INIT_WORK(&timer->expired, kvm_timer_inject_irq_work);
>> hrtimer_init(&timer->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
>> timer->timer.function = kvm_timer_expire;
>> - timer->irq = &timer_irq;
>> + timer->irq = NULL;
>
> How useful is that? The vcpu has been kzalloc-ed anyway. Is there any case
> where this makes sense?
Ok, will remove this.
>
>> }
>>
>> static void kvm_timer_init_interrupt(void *info)
>> {
>> - enable_percpu_irq(timer_irq.irq, 0);
>> + enable_percpu_irq(host_timer_irq.irq, 0);
>> }
>>
>>
>> @@ -182,7 +203,7 @@ static int kvm_timer_cpu_notify(struct
> notifier_block
>> *self,
>> break;
>> case CPU_DYING:
>> case CPU_DYING_FROZEN:
>> - disable_percpu_irq(timer_irq.irq);
>> + disable_percpu_irq(host_timer_irq.irq);
>> break;
>> }
>>
>> @@ -230,7 +251,7 @@ int kvm_timer_hyp_init(void)
>> goto out;
>> }
>>
>> - timer_irq.irq = ppi;
>> + host_timer_irq.irq = ppi;
>>
>> err = register_cpu_notifier(&kvm_timer_cpu_nb);
>> if (err) {
>> diff --git a/arch/arm/kvm/reset.c b/arch/arm/kvm/reset.c
>> index b80256b..148397e 100644
>> --- a/arch/arm/kvm/reset.c
>> +++ b/arch/arm/kvm/reset.c
>> @@ -26,6 +26,7 @@
>> #include <asm/cputype.h>
>> #include <asm/kvm_arm.h>
>> #include <asm/kvm_coproc.h>
>> +#include <asm/kvm_arch_timer.h>
>>
>>
> /******************************************************************************
>> * Cortex-A15 Reset Values
>> @@ -37,6 +38,11 @@ static struct kvm_regs a15_regs_reset = {
>> .usr_regs.ARM_cpsr = SVC_MODE | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT,
>> };
>>
>> +static struct kvm_irq_level a15_timer_irq = {
>
> Please make this static const.
Ok, will make it static const.
>
>> + .irq = 27,
>> + .level = 1,
>> +};
>> +
>>
>>
> /*******************************************************************************
>> * Exported reset function
>> @@ -52,6 +58,7 @@ static struct kvm_regs a15_regs_reset = {
>> int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
>> {
>> struct kvm_regs *cpu_reset;
>> + const struct kvm_irq_level *cpu_irq;
>>
>> switch (vcpu->arch.target) {
>> case KVM_ARM_TARGET_CORTEX_A15:
>> @@ -59,6 +66,7 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
>> return -EINVAL;
>> cpu_reset = &a15_regs_reset;
>> vcpu->arch.midr = read_cpuid_id();
>> + cpu_irq = &a15_timer_irq;
>> break;
>> default:
>> return -ENODEV;
>> @@ -70,5 +78,6 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
>> /* Reset CP15 registers */
>> kvm_reset_coprocs(vcpu);
>>
>> - return 0;
>> + /* Reset arch_timer context */
>> + return kvm_timer_vcpu_reset(vcpu, cpu_irq);
>> }
>
> Some of the above comments also apply to the arm64 you sent.
Sure, I will update that patch too.
>
> Thanks,
>
> M.
> --
> Fast, cheap, reliable. Pick two.
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--Anup
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