linux-kernel - Re: [PATCH 3/6] KVM: x86: preparatory changes for APICv cleanups

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Message-ID: <20170207182046.GC31091@potion>
Date:   Tue, 7 Feb 2017 19:20:46 +0100
From:   Radim Krčmář <rkrcmar@...hat.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH 3/6] KVM: x86: preparatory changes for APICv cleanups

2016-12-19 17:17+0100, Paolo Bonzini:
> Add return value to __kvm_apic_update_irr/kvm_apic_update_irr.
> Move vmx_sync_pir_to_irr around.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
> ---

Reviewed-by: Radim Krčmář <rkrcmar@...hat.com>

>  arch/x86/kvm/lapic.c | 25 +++++++++++++++++--------
>  arch/x86/kvm/lapic.h |  4 ++--
>  arch/x86/kvm/vmx.c   | 32 ++++++++++++++++----------------
>  3 files changed, 35 insertions(+), 26 deletions(-)
> 
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index 5fa546e27b7e..4c76c602576e 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -341,7 +341,7 @@ static int find_highest_vector(void *bitmap)
>  	     vec >= 0; vec -= APIC_VECTORS_PER_REG) {
>  		reg = bitmap + REG_POS(vec);
>  		if (*reg)
> -			return fls(*reg) - 1 + vec;
> +			return __fls(*reg) + vec;
>  	}
>  
>  	return -1;
> @@ -361,27 +361,36 @@ static u8 count_vectors(void *bitmap)
>  	return count;
>  }
>  
> -void __kvm_apic_update_irr(u32 *pir, void *regs)
> +int __kvm_apic_update_irr(u32 *pir, void *regs)
>  {
> -	u32 i, pir_val;
> +	u32 i, vec;
> +	u32 pir_val, irr_val;
> +	int max_irr = -1;
>  
> -	for (i = 0; i <= 7; i++) {
> +	for (i = vec = 0; i <= 7; i++, vec += 32) {
>  		pir_val = READ_ONCE(pir[i]);
> +		irr_val = *((u32 *)(regs + APIC_IRR + i * 0x10));
>  		if (pir_val) {
> -			pir_val = xchg(&pir[i], 0);
> -			*((u32 *)(regs + APIC_IRR + i * 0x10)) |= pir_val;
> +			irr_val |= xchg(&pir[i], 0);
> +			*((u32 *)(regs + APIC_IRR + i * 0x10)) = irr_val;
>  		}
> +		if (irr_val)
> +			max_irr = __fls(irr_val) + vec;
>  	}
> +
> +	return max_irr;
>  }
>  EXPORT_SYMBOL_GPL(__kvm_apic_update_irr);
>  
> -void kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir)
> +int kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir)
>  {
>  	struct kvm_lapic *apic = vcpu->arch.apic;
> +	int max_irr;
>  
> -	__kvm_apic_update_irr(pir, apic->regs);
> +	max_irr = __kvm_apic_update_irr(pir, apic->regs);
>  
>  	kvm_make_request(KVM_REQ_EVENT, vcpu);
> +	return max_irr;
>  }
>  EXPORT_SYMBOL_GPL(kvm_apic_update_irr);
>  
> diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
> index 5b5b1ba644cb..8aa54fdc43d1 100644
> --- a/arch/x86/kvm/lapic.h
> +++ b/arch/x86/kvm/lapic.h
> @@ -71,8 +71,8 @@ int kvm_lapic_reg_read(struct kvm_lapic *apic, u32 offset, int len,
>  bool kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source,
>  			   int short_hand, unsigned int dest, int dest_mode);
>  
> -void __kvm_apic_update_irr(u32 *pir, void *regs);
> -void kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir);
> +int __kvm_apic_update_irr(u32 *pir, void *regs);
> +int kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir);
>  void kvm_apic_update_ppr(struct kvm_vcpu *vcpu);
>  int kvm_apic_set_irq(struct kvm_vcpu *vcpu, struct kvm_lapic_irq *irq,
>  		     struct dest_map *dest_map);
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 661956caf162..eab8ab023705 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -5068,22 +5068,6 @@ static void vmx_deliver_posted_interrupt(struct kvm_vcpu *vcpu, int vector)
>  		kvm_vcpu_kick(vcpu);
>  }
>  
> -static void vmx_sync_pir_to_irr(struct kvm_vcpu *vcpu)
> -{
> -	struct vcpu_vmx *vmx = to_vmx(vcpu);
> -
> -	if (!pi_test_on(&vmx->pi_desc))
> -		return;
> -
> -	pi_clear_on(&vmx->pi_desc);
> -	/*
> -	 * IOMMU can write to PIR.ON, so the barrier matters even on UP.
> -	 * But on x86 this is just a compiler barrier anyway.
> -	 */
> -	smp_mb__after_atomic();
> -	kvm_apic_update_irr(vcpu, vmx->pi_desc.pir);
> -}
> -
>  /*
>   * Set up the vmcs's constant host-state fields, i.e., host-state fields that
>   * will not change in the lifetime of the guest.
> @@ -8750,6 +8734,22 @@ static void vmx_hwapic_irr_update(struct kvm_vcpu *vcpu, int max_irr)
>  	}
>  }
>  
> +static void vmx_sync_pir_to_irr(struct kvm_vcpu *vcpu)
> +{
> +	struct vcpu_vmx *vmx = to_vmx(vcpu);
> +
> +	if (!pi_test_on(&vmx->pi_desc))
> +		return;
> +
> +	pi_clear_on(&vmx->pi_desc);
> +	/*
> +	 * IOMMU can write to PIR.ON, so the barrier matters even on UP.
> +	 * But on x86 this is just a compiler barrier anyway.
> +	 */
> +	smp_mb__after_atomic();
> +	kvm_apic_update_irr(vcpu, vmx->pi_desc.pir);
> +}
> +
>  static void vmx_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
>  {
>  	if (!kvm_vcpu_apicv_active(vcpu))
> -- 
> 1.8.3.1
> 
> 
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