Zhang, Yang Z wrote on 2012-12-06:
> Marcelo Tosatti wrote on 2012-12-06:
>> On Mon, Dec 03, 2012 at 03:01:03PM +0800, Yang Zhang wrote:
>>> Virtual interrupt delivery avoids KVM to inject vAPIC interrupts
>>> manually, which is fully taken care of by the hardware. This needs
>>> some special awareness into existing interrupr injection path:
>>> 
>>> - for pending interrupt, instead of direct injection, we may need
>>>   update architecture specific indicators before resuming to guest. -
>>>   A pending interrupt, which is masked by ISR, should be also
>>>   considered in above update action, since hardware will decide when
>>>   to inject it at right time. Current has_interrupt and get_interrupt
>>>   only returns a valid vector from injection p.o.v.
>>> Signed-off-by: Yang Zhang <yang.z.zh...@intel.com>
>>> Signed-off-by: Kevin Tian <kevin.t...@intel.com>
>>> ---
>>>  arch/x86/include/asm/kvm_host.h |    4 + arch/x86/include/asm/vmx.h
>>>    |   11 +++ arch/x86/kvm/irq.c              |   53 ++++++++++-----
>>>  arch/x86/kvm/lapic.c            |   56 +++++++++++++---
>>>  arch/x86/kvm/lapic.h            |    6 ++ arch/x86/kvm/svm.c
>>>     |   19 +++++ arch/x86/kvm/vmx.c              |  140
>>>  ++++++++++++++++++++++++++++++++++++++- arch/x86/kvm/x86.c
>>>   |   34 ++++++++-- virt/kvm/ioapic.c               |    1 + 9 files
>>>  changed, 291 insertions(+), 33 deletions(-)
>>> diff --git a/arch/x86/include/asm/kvm_host.h
>>> b/arch/x86/include/asm/kvm_host.h index dc87b65..e5352c8 100644 ---
>>> a/arch/x86/include/asm/kvm_host.h +++
>>> b/arch/x86/include/asm/kvm_host.h @@ -697,6 +697,10 @@ struct
>>> kvm_x86_ops {
>>>     void (*enable_nmi_window)(struct kvm_vcpu *vcpu);
>>>     void (*enable_irq_window)(struct kvm_vcpu *vcpu);
>>>     void (*update_cr8_intercept)(struct kvm_vcpu *vcpu, int tpr, int irr);
>>> +   int (*has_virtual_interrupt_delivery)(struct kvm_vcpu *vcpu);
>>> +   void (*update_irq)(struct kvm_vcpu *vcpu);
>>> +   void (*set_eoi_exitmap)(struct kvm_vcpu *vcpu, int vector,
>>> +                   int trig_mode, int always_set);
>>>     int (*set_tss_addr)(struct kvm *kvm, unsigned int addr);
>>>     int (*get_tdp_level)(void);
>>>     u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool
> is_mmio);
>>> diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
>>> index 21101b6..1003341 100644
>>> --- a/arch/x86/include/asm/vmx.h
>>> +++ b/arch/x86/include/asm/vmx.h
>>> @@ -62,6 +62,7 @@
>>>  #define EXIT_REASON_MCE_DURING_VMENTRY  41 #define
>>>  EXIT_REASON_TPR_BELOW_THRESHOLD 43 #define
> EXIT_REASON_APIC_ACCESS
>>>      44 +#define EXIT_REASON_EOI_INDUCED         45 #define
>>>  EXIT_REASON_EPT_VIOLATION       48 #define
> EXIT_REASON_EPT_MISCONFIG
>>>      49 #define EXIT_REASON_WBINVD              54 @@ -143,6
> +144,7 @@
>>>  #define SECONDARY_EXEC_WBINVD_EXITING              0x00000040 #define
>>>  SECONDARY_EXEC_UNRESTRICTED_GUEST  0x00000080 #define
>>>  SECONDARY_EXEC_APIC_REGISTER_VIRT       0x00000100 +#define
>>>  SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY    0x00000200 #define
>>>  SECONDARY_EXEC_PAUSE_LOOP_EXITING  0x00000400 #define
>>>  SECONDARY_EXEC_ENABLE_INVPCID              0x00001000 @@ -180,6 +182,7 @@ 
>>> enum
>>>  vmcs_field {       GUEST_GS_SELECTOR               = 0x0000080a,
>       GUEST_LDTR_SELECTOR
>>>           = 0x0000080c,     GUEST_TR_SELECTOR               =
> 0x0000080e,
>>>  +  GUEST_INTR_STATUS               = 0x00000810,
>       HOST_ES_SELECTOR
>>>            = 0x00000c00,    HOST_CS_SELECTOR                =
> 0x00000c02,
>>>     HOST_SS_SELECTOR                = 0x00000c04, @@ -207,6 +210,14 @@
>>>  enum vmcs_field {  APIC_ACCESS_ADDR_HIGH           = 0x00002015,
>       EPT_POINTER
>>>                    = 0x0000201a,    EPT_POINTER_HIGH
> =
>>>  0x0000201b,
>>> +   EOI_EXIT_BITMAP0                = 0x0000201c,
>>> +   EOI_EXIT_BITMAP0_HIGH           = 0x0000201d,
>>> +   EOI_EXIT_BITMAP1                = 0x0000201e,
>>> +   EOI_EXIT_BITMAP1_HIGH           = 0x0000201f,
>>> +   EOI_EXIT_BITMAP2                = 0x00002020,
>>> +   EOI_EXIT_BITMAP2_HIGH           = 0x00002021,
>>> +   EOI_EXIT_BITMAP3                = 0x00002022,
>>> +   EOI_EXIT_BITMAP3_HIGH           = 0x00002023,
>>>     GUEST_PHYSICAL_ADDRESS          = 0x00002400,
>>>     GUEST_PHYSICAL_ADDRESS_HIGH     = 0x00002401,
>>>     VMCS_LINK_POINTER               = 0x00002800,
>>> diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c
>>> index 7e06ba1..f782788 100644
>>> --- a/arch/x86/kvm/irq.c
>>> +++ b/arch/x86/kvm/irq.c
>>> @@ -43,45 +43,64 @@ EXPORT_SYMBOL(kvm_cpu_has_pending_timer);
>>>   */
>>>  int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
>>>  {
>>> -   struct kvm_pic *s;
>>> -
>>>     if (!irqchip_in_kernel(v->kvm))
>>>             return v->arch.interrupt.pending;
>>> -   if (kvm_apic_has_interrupt(v) == -1) {  /* LAPIC */
>>> -           if (kvm_apic_accept_pic_intr(v)) {
>>> -                   s = pic_irqchip(v->kvm);        /* PIC */
>>> -                   return s->output;
>>> -           } else
>>> -                   return 0;
>>> -   }
>>> +   if (kvm_apic_has_interrupt(v) == -1) /* LAPIC */
>>> +           return kvm_cpu_has_extint(v); /* non-APIC */
>>>     return 1;
>>>  }
>>>  EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
>>>  
>>>  /*
>>> + * check if there is pending interrupt from
>>> + * non-APIC source without intack.
>>> + */
>>> +int kvm_cpu_has_extint(struct kvm_vcpu *v)
>>> +{
>>> +   struct kvm_pic *s;
>>> +
>>> +   if (kvm_apic_accept_pic_intr(v)) {
>>> +           s = pic_irqchip(v->kvm); /* PIC */
>>> +           return s->output;
>>> +   } else
>>> +           return 0;
>>> +}
>>> +
>>> +/*
>>>   * Read pending interrupt vector and intack.
>>>   */
>>>  int kvm_cpu_get_interrupt(struct kvm_vcpu *v) { -  struct kvm_pic *s;
>>>     int vector;
>>>  
>>>     if (!irqchip_in_kernel(v->kvm))
>>>             return v->arch.interrupt.nr;
>>>  
>>>     vector = kvm_get_apic_interrupt(v);     /* APIC */
>>> -   if (vector == -1) {
>>> -           if (kvm_apic_accept_pic_intr(v)) {
>>> -                   s = pic_irqchip(v->kvm);
>>> -                   s->output = 0;          /* PIC */
>>> -                   vector = kvm_pic_read_irq(v->kvm);
>>> -           }
>>> -   }
>>> +   if (vector == -1)
>>> +           return kvm_cpu_get_extint(v); /* non-APIC */
>>>     return vector;
>>>  }
>>>  EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
>>> +/*
>>> + * Read pending interrupt(from non-APIC source)
>>> + * vector and intack.
>>> + */
>>> +int kvm_cpu_get_extint(struct kvm_vcpu *v)
>>> +{
>>> +   struct kvm_pic *s;
>>> +   int vector = -1;
>>> +
>>> +   if (kvm_apic_accept_pic_intr(v)) {
>>> +           s = pic_irqchip(v->kvm);
>>> +           s->output = 0;          /* PIC */
>>> +           vector = kvm_pic_read_irq(v->kvm);
>>> +   }
>>> +   return vector;
>>> +}
>>> +
>>>  void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
>>>  {
>>>     kvm_inject_apic_timer_irqs(vcpu);
>>> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
>>> index 7c96012..400d3ba 100644
>>> --- a/arch/x86/kvm/lapic.c
>>> +++ b/arch/x86/kvm/lapic.c
>>> @@ -643,6 +643,14 @@ out:
>>>     return ret;
>>>  }
>>> +void kvm_set_eoi_exitmap(struct kvm_vcpu *vcpu, int vector,
>>> +           int trig_mode, int always_set)
>>> +{
>>> +   if (kvm_x86_ops->set_eoi_exitmap)
>>> +           kvm_x86_ops->set_eoi_exitmap(vcpu, vector,
>>> +                                   trig_mode, always_set);
>>> +}
>>> +
>>>  /*
>>>   * Add a pending IRQ into lapic.
>>>   * Return 1 if successfully added and 0 if discarded.
>>> @@ -661,6 +669,7 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int
>> delivery_mode,
>>>             if (unlikely(!apic_enabled(apic)))                      break;
>>>  +          kvm_set_eoi_exitmap(vcpu, vector, trig_mode, 0);                
>>> if (trig_mode)
>>>  {                  apic_debug("level trig mode for vector %d", vector);
>>>                     apic_set_vector(vector, apic->regs + APIC_TMR);
>>> @@ -740,6 +749,19 @@ int kvm_apic_compare_prio(struct kvm_vcpu *vcpu1,
>> struct kvm_vcpu *vcpu2)
>>>     return vcpu1->arch.apic_arb_prio - vcpu2->arch.apic_arb_prio;
>>>  }
>>> +static void kvm_ioapic_send_eoi(struct kvm_lapic *apic, int vector)
>>> +{
>>> +   if (!(kvm_apic_get_reg(apic, APIC_SPIV) & APIC_SPIV_DIRECTED_EOI) &&
>>> +       kvm_ioapic_handles_vector(apic->vcpu->kvm, vector)) {
>>> +           int trigger_mode;
>>> +           if (apic_test_vector(vector, apic->regs + APIC_TMR))
>>> +                   trigger_mode = IOAPIC_LEVEL_TRIG;
>>> +           else
>>> +                   trigger_mode = IOAPIC_EDGE_TRIG;
>>> +           kvm_ioapic_update_eoi(apic->vcpu->kvm, vector, trigger_mode);
>>> +   }
>>> +}
>>> +
>>>  static int apic_set_eoi(struct kvm_lapic *apic) {  int vector =
>>>  apic_find_highest_isr(apic); @@ -756,19 +778,24 @@ static int
>>>  apic_set_eoi(struct kvm_lapic *apic)       apic_clear_isr(vector, apic);
>>>     apic_update_ppr(apic);
>>> -   if (!(kvm_apic_get_reg(apic, APIC_SPIV) & APIC_SPIV_DIRECTED_EOI) &&
>>> -       kvm_ioapic_handles_vector(apic->vcpu->kvm, vector)) {
>>> -           int trigger_mode;
>>> -           if (apic_test_vector(vector, apic->regs + APIC_TMR))
>>> -                   trigger_mode = IOAPIC_LEVEL_TRIG;
>>> -           else
>>> -                   trigger_mode = IOAPIC_EDGE_TRIG;
>>> -           kvm_ioapic_update_eoi(apic->vcpu->kvm, vector, trigger_mode);
>>> -   }
>>> +   kvm_ioapic_send_eoi(apic, vector);
>>>     kvm_make_request(KVM_REQ_EVENT, apic->vcpu);
>>>     return vector;
>>>  }
>>> +/*
>>> + * this interface assumes a trap-like exit, which has already finished
>>> + * desired side effect including vISR and vPPR update.
>>> + */
>>> +void kvm_apic_set_eoi_accelerated(struct kvm_vcpu *vcpu, int vector)
>>> +{
>>> +   struct kvm_lapic *apic = vcpu->arch.apic;
>>> +
>>> +   kvm_ioapic_send_eoi(apic, vector);
>>> +   kvm_make_request(KVM_REQ_EVENT, apic->vcpu);
>>> +}
>>> +EXPORT_SYMBOL_GPL(kvm_apic_set_eoi_accelerated);
>>> +
>>>  static void apic_send_ipi(struct kvm_lapic *apic) {        u32 icr_low =
>>>  kvm_apic_get_reg(apic, APIC_ICR); @@ -1533,6 +1560,17 @@ int
>>>  kvm_apic_has_interrupt(struct kvm_vcpu *vcpu)      return highest_irr; }
>>> +int kvm_apic_get_highest_irr(struct kvm_vcpu *vcpu)
>>> +{
>>> +   struct kvm_lapic *apic = vcpu->arch.apic;
>>> +
>>> +   if (!apic || !apic_enabled(apic))
>>> +           return -1;
>>> +
>>> +   return apic_find_highest_irr(apic);
>>> +}
>> 
>> irr_pending of apic_find_highest_irr() is meaningless (stale) if
>> HW is updating VIRR.
> I don't think target vcpu is running when we call this function. So it is 
> safe to
> check irr_pending and read the irr.
One problem is that when HW clears VIRR, after vmexit, the irr_peding will 
still true if there are more than one bit is set in VIRR in last vmentry.
How about to recaculate irr_pending according the VIRR on each vmexit?

Best regards,
Yang


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