On Sun, Dec 11, 2011 at 10:18 AM, Jan Kiszka <jan.kiszka@xxxxxx> wrote:
> Just found two, maybe three nits while browsing by:
>
> On 2011-12-11 11:24, Christoffer Dall wrote:
>> Userspace can inject IRQs and FIQs through the KVM_IRQ_LINE VM ioctl.
>> This ioctl is used since the sematics are in fact two lines that can be
>> either raised or lowered on the VCPU - the IRQ and FIQ lines.
>>
>> KVM needs to know which VCPU it must operate on and whether the FIQ or
>> IRQ line is raised/lowered. Hence both pieces of information is packed
>> in the kvm_irq_level->irq field. The irq fild value will be:
>> IRQ: vcpu_index * 2
>> FIQ: (vcpu_index * 2) + 1
>>
>> This is documented in Documentation/kvm/api.txt.
>>
>> The effect of the ioctl is simply to simply raise/lower the
>> corresponding virt_irq field on the VCPU struct, which will cause the
>> world-switch code to raise/lower virtual interrupts when running the
>> guest on next switch. The wait_for_interrupt flag is also cleared for
>> raised IRQs causing an idle VCPU to become active again.
>>
>> Note: The custom trace_kvm_irq_line is used despite a generic definition of
>> trace_kvm_set_irq, since the trace-Kvm_set_irq depends on the x86-specific
>> define of __HAVE_IOAPIC. Either the trace event should be created
>> regardless of this define or it should depend on another ifdef clause,
>> common for both x86 and ARM. However, since the arguments don't really
>> match those used in ARM, I am yet to be convinced why this is necessary.
>>
>> Signed-off-by: Christoffer Dall <c.dall@xxxxxxxxxxxxxxxxxxxxxx>
>> ---
>> Documentation/virtual/kvm/api.txt | 10 ++++++-
>> arch/arm/include/asm/kvm.h | 8 ++++++
>> arch/arm/include/asm/kvm_arm.h | 1 +
>> arch/arm/kvm/arm.c | 53 ++++++++++++++++++++++++++++++++++++-
>> arch/arm/kvm/trace.h | 21 +++++++++++++++
>> include/linux/kvm.h | 1 +
>> 6 files changed, 91 insertions(+), 3 deletions(-)
>>
>> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
>> index 7945b0b..4abaa67 100644
>> --- a/Documentation/virtual/kvm/api.txt
>> +++ b/Documentation/virtual/kvm/api.txt
>> @@ -572,7 +572,7 @@ only go to the IOAPIC. On ia64, a IOSAPIC is created.
>> 4.25 KVM_IRQ_LINE
>>
>> Capability: KVM_CAP_IRQCHIP
>> -Architectures: x86, ia64
>> +Architectures: x86, ia64, arm
>> Type: vm ioctl
>> Parameters: struct kvm_irq_level
>> Returns: 0 on success, -1 on error
>> @@ -582,6 +582,14 @@ Requires that an interrupt controller model has been previously created with
>> KVM_CREATE_IRQCHIP. Note that edge-triggered interrupts require the level
>> to be set to 1 and then back to 0.
>>
>> +KVM_CREATE_IRQCHIP (except for ARM). Note that edge-triggered interrupts
>> +require the level to be set to 1 and then back to 0.
>
> You probably wanted to replace the original lines with these two, no?
>
ah yes, some stgit re-ordering artifact.
>> +
>> +ARM uses two types of interrupt lines per CPU, ie. IRQ and FIQ. The value of the
>> +irq field should be (VCPU_INDEX * 2) for IRQs and ((VCPU_INDEX * 2) + 1) for
>> +FIQs. Level is used to raise/lower the line. See arch/arm/include/asm/kvm.h for
>> +convenience macros.
>> +
>> struct kvm_irq_level {
>> union {
>> __u32 irq; /* GSI */
>> diff --git a/arch/arm/include/asm/kvm.h b/arch/arm/include/asm/kvm.h
>> index 87dc33b..8935062 100644
>> --- a/arch/arm/include/asm/kvm.h
>> +++ b/arch/arm/include/asm/kvm.h
>> @@ -20,6 +20,14 @@
>> #include <asm/types.h>
>>
>> /*
>> + * KVM_IRQ_LINE macros to set/read IRQ/FIQ for specific VCPU index.
>> + */
>> +enum KVM_ARM_IRQ_LINE_TYPE {
>> + KVM_ARM_IRQ_LINE = 0,
>> + KVM_ARM_FIQ_LINE = 1,
>> +};
>> +
>> +/*
>> * Modes used for short-hand mode determinition in the world-switch code and
>> * in emulation code.
>> *
>> diff --git a/arch/arm/include/asm/kvm_arm.h b/arch/arm/include/asm/kvm_arm.h
>> index 835abd1..e378a37 100644
>> --- a/arch/arm/include/asm/kvm_arm.h
>> +++ b/arch/arm/include/asm/kvm_arm.h
>> @@ -49,6 +49,7 @@
>> #define HCR_VM 1
>> #define HCR_GUEST_MASK (HCR_TSC | HCR_TWE | HCR_TWI | HCR_VM | HCR_AMO | \
>> HCR_AMO | HCR_IMO | HCR_FMO | HCR_SWIO)
>> +#define HCR_VIRT_EXCP_MASK (HCR_VA | HCR_VI | HCR_VF)
>>
>> /* Hyp System Control Register (HSCTLR) bits */
>> #define HSCTLR_TE (1 << 30)
>> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
>> index 89ba18d..fc0bd6b 100644
>> --- a/arch/arm/kvm/arm.c
>> +++ b/arch/arm/kvm/arm.c
>> @@ -299,6 +299,43 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
>> return -EINVAL;
>> }
>>
>> +static int kvm_arch_vm_ioctl_irq_line(struct kvm *kvm,
>> + struct kvm_irq_level *irq_level)
>> +{
>> + u32 mask;
>> + unsigned int vcpu_idx;
>> + struct kvm_vcpu *vcpu;
>> +
>> + vcpu_idx = irq_level->irq / 2;
>> + if (vcpu_idx >= KVM_MAX_VCPUS)
>> + return -EINVAL;
>> +
>> + vcpu = kvm_get_vcpu(kvm, vcpu_idx);
>> + if (!vcpu)
>> + return -EINVAL;
>> +
>> + switch (irq_level->irq % 2) {
>> + case KVM_ARM_IRQ_LINE:
>> + mask = HCR_VI;
>> + break;
>> + case KVM_ARM_FIQ_LINE:
>> + mask = HCR_VF;
>> + break;
>> + default:
>> + return -EINVAL;
>
> Due to % 2, default is unreachable. Remove the masking?
>
nah, the masking should be there, it's just th default case that should go away.
>> + }
>> +
>> + trace_kvm_irq_line(irq_level->irq % 2, irq_level->level, vcpu_idx);
>> +
>> + if (irq_level->level) {
>> + vcpu->arch.virt_irq |= mask;
>> + vcpu->arch.wait_for_interrupts = 0;
>> + } else
>> + vcpu->arch.virt_irq &= ~mask;
>
> No need to protect the bitops on virt_irq? Or what lock does this?
>
that's fixed in the SMP host patch (but I guess with I/O thread that
doesn't really apply only to SMP, so I could move that logging down
the patch stream. In any case, yes, there should be locking, and there
is).
>> +
>> + return 0;
>> +}
>> +
>> long kvm_arch_vcpu_ioctl(struct file *filp,
>> unsigned int ioctl, unsigned long arg)
>> {
>> @@ -313,8 +350,20 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
>> long kvm_arch_vm_ioctl(struct file *filp,
>> unsigned int ioctl, unsigned long arg)
>> {
>> - printk(KERN_ERR "kvm_arch_vm_ioctl: Unsupported ioctl (%d)\n", ioctl);
>> - return -EINVAL;
>> + struct kvm *kvm = filp->private_data;
>> + void __user *argp = (void __user *)arg;
>> +
>> + switch (ioctl) {
>> + case KVM_IRQ_LINE: {
>> + struct kvm_irq_level irq_event;
>> +
>> + if (copy_from_user(&irq_event, argp, sizeof irq_event))
>> + return -EFAULT;
>> + return kvm_arch_vm_ioctl_irq_line(kvm, &irq_event);
>> + }
>> + default:
>> + return -EINVAL;
>> + }
>> }
>>
>> /**
>> diff --git a/arch/arm/kvm/trace.h b/arch/arm/kvm/trace.h
>> index f8869c1..ac64e3a 100644
>> --- a/arch/arm/kvm/trace.h
>> +++ b/arch/arm/kvm/trace.h
>> @@ -40,6 +40,27 @@ TRACE_EVENT(kvm_exit,
>> );
>>
>>
>> +TRACE_EVENT(kvm_irq_line,
>> + TP_PROTO(unsigned int type, unsigned int level, unsigned int vcpu_idx),
>> + TP_ARGS(type, level, vcpu_idx),
>> +
>> + TP_STRUCT__entry(
>> + __field( unsigned int, type )
>> + __field( unsigned int, level )
>> + __field( unsigned int, vcpu_idx )
>> + ),
>> +
>> + TP_fast_assign(
>> + __entry->type = type;
>> + __entry->level = level;
>> + __entry->vcpu_idx = vcpu_idx;
>> + ),
>> +
>> + TP_printk("KVM_IRQ_LINE: type: %s, level: %u, vcpu: %u",
>> + (__entry->type == KVM_ARM_IRQ_LINE) ? "IRQ" : "FIQ",
>> + __entry->level, __entry->vcpu_idx)
>> +);
>> +
>>
>> #endif /* _TRACE_KVM_H */
>>
>> diff --git a/include/linux/kvm.h b/include/linux/kvm.h
>> index c3892fc..679abbb 100644
>> --- a/include/linux/kvm.h
>> +++ b/include/linux/kvm.h
>> @@ -111,6 +111,7 @@ struct kvm_irq_level {
>> * ACPI gsi notion of irq.
>> * For IA-64 (APIC model) IOAPIC0: irq 0-23; IOAPIC1: irq 24-47..
>> * For X86 (standard AT mode) PIC0/1: irq 0-15. IOAPIC0: 0-23..
>> + * For ARM: IRQ: irq = (2*vcpu_index). FIQ: irq = (2*vcpu_indx + 1).
>> */
>> union {
>> __u32 irq;
>>
Thanks,
-Christoffer
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