Subject: [PATCH v3 11/19] KVM: ARM: vgic: abstract VMCR access

From: [email-masked] (Christoffer Dall)
Date: Fri, 9 May 2014 16:06:33 +0200

On Wed, Apr 16, 2014 at 02:39:43PM +0100, Marc Zyngier wrote:
> Instead of directly messing with with the GICH_VMCR bits for the CPU
> interface save/restore code, add accessors that encode/decode the
> entire set of registers exposed by VMCR.
> 
> Not the most efficient thing, but given that this code is only used
> by the save/restore code, performance is far from being critical.
> 
> Signed-off-by: Marc Zyngier <[email-masked]>
> ---
>  include/kvm/arm_vgic.h |  9 +++++++
>  virt/kvm/arm/vgic.c    | 69 ++++++++++++++++++++++++++++++++++++++------------
>  2 files changed, 62 insertions(+), 16 deletions(-)
> 
> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> index 831b9f5..0017253 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -81,6 +81,13 @@ struct vgic_lr {
>  	u8	state;
>  };
>  
> +struct vgic_vmcr {
> +	u32	ctlr;
> +	u32	abpr;
> +	u32	bpr;
> +	u32	pmr;
> +};
> +
>  struct vgic_ops {
>  	struct vgic_lr	(*get_lr)(const struct kvm_vcpu *, int);
>  	void	(*set_lr)(struct kvm_vcpu *, int, struct vgic_lr);
> @@ -89,6 +96,8 @@ struct vgic_ops {
>  	u32	(*get_interrupt_status)(const struct kvm_vcpu *vcpu);
>  	void	(*set_underflow)(struct kvm_vcpu *vcpu);
>  	void	(*clear_underflow)(struct kvm_vcpu *vcpu);
> +	void	(*get_vmcr)(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
> +	void	(*set_vmcr)(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
>  };
>  
>  struct vgic_dist {
> diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
> index 13dad1f..574ca47 100644
> --- a/virt/kvm/arm/vgic.c
> +++ b/virt/kvm/arm/vgic.c
> @@ -100,8 +100,10 @@ static void vgic_kick_vcpus(struct kvm *kvm);
>  static void vgic_dispatch_sgi(struct kvm_vcpu *vcpu, u32 reg);
>  static struct vgic_lr vgic_get_lr(const struct kvm_vcpu *vcpu, int lr);
>  static void vgic_set_lr(struct kvm_vcpu *vcpu, int lr, struct vgic_lr lr_desc);
> -static u32 vgic_nr_lr;
> +static void vgic_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
> +static void vgic_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
>  
> +static u32 vgic_nr_lr;
>  static unsigned int vgic_maint_irq;
>  
>  static u32 *vgic_bitmap_get_reg(struct vgic_bitmap *x,
> @@ -1057,6 +1059,28 @@ static void vgic_v2_clear_underflow(struct kvm_vcpu *vcpu)
>  	vcpu->arch.vgic_cpu.vgic_v2.vgic_hcr &= ~GICH_HCR_UIE;
>  }
>  
> +static void vgic_v2_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
> +{
> +	u32 vmcr = vcpu->arch.vgic_cpu.vgic_v2.vgic_vmcr;
> +
> +	vmcrp->ctlr = (vmcr & GICH_VMCR_CTRL_MASK) >> GICH_VMCR_CTRL_SHIFT;
> +	vmcrp->abpr = (vmcr & GICH_VMCR_ALIAS_BINPOINT_MASK) >> GICH_VMCR_ALIAS_BINPOINT_SHIFT;
> +	vmcrp->bpr  = (vmcr & GICH_VMCR_BINPOINT_MASK) >> GICH_VMCR_BINPOINT_SHIFT;
> +	vmcrp->pmr  = (vmcr & GICH_VMCR_PRIMASK_MASK) >> GICH_VMCR_PRIMASK_SHIFT;
> +}
> +
> +static void vgic_v2_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
> +{
> +	u32 vmcr;
> +
> +	vmcr  = (vmcrp->ctlr << GICH_VMCR_CTRL_SHIFT) & GICH_VMCR_CTRL_MASK;
> +	vmcr |= (vmcrp->abpr << GICH_VMCR_ALIAS_BINPOINT_SHIFT) & GICH_VMCR_ALIAS_BINPOINT_MASK;
> +	vmcr |= (vmcrp->bpr << GICH_VMCR_BINPOINT_SHIFT) & GICH_VMCR_BINPOINT_MASK;
> +	vmcr |= (vmcrp->pmr << GICH_VMCR_PRIMASK_SHIFT) & GICH_VMCR_PRIMASK_MASK;
> +
> +	vcpu->arch.vgic_cpu.vgic_v2.vgic_vmcr = vmcr;

did you forget to add this field to the vgic_v2 struct as part of this patch?

> +}
> +
>  static const struct vgic_ops vgic_ops = {
>  	.get_lr			= vgic_v2_get_lr,
>  	.set_lr			= vgic_v2_set_lr,
> @@ -1065,6 +1089,8 @@ static const struct vgic_ops vgic_ops = {
>  	.get_interrupt_status	= vgic_v2_get_interrupt_status,
>  	.set_underflow		= vgic_v2_set_underflow,
>  	.clear_underflow	= vgic_v2_clear_underflow,
> +	.get_vmcr		= vgic_v2_get_vmcr,
> +	.set_vmcr		= vgic_v2_set_vmcr,
>  };
>  
>  static inline struct vgic_lr vgic_get_lr(const struct kvm_vcpu *vcpu, int lr)
> @@ -1103,6 +1129,16 @@ static inline void vgic_clear_underflow(struct kvm_vcpu *vcpu)
>  	vgic_ops.clear_underflow(vcpu);
>  }
>  
> +static inline void vgic_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr)
> +{
> +	vgic_ops.get_vmcr(vcpu, vmcr);
> +}
> +
> +static void vgic_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr)
> +{
> +	vgic_ops.set_vmcr(vcpu, vmcr);
> +}
> +
>  static void vgic_retire_lr(int lr_nr, int irq, struct kvm_vcpu *vcpu)
>  {
>  	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> @@ -1847,39 +1883,40 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
>  static bool handle_cpu_mmio_misc(struct kvm_vcpu *vcpu,
>  				 struct kvm_exit_mmio *mmio, phys_addr_t offset)
>  {
> -	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> -	u32 reg, mask = 0, shift = 0;
>  	bool updated = false;
> +	struct vgic_vmcr vmcr;
> +	u32 *vmcr_field;
> +	u32 reg;
> +
> +	vgic_get_vmcr(vcpu, &vmcr);
>  
>  	switch (offset & ~0x3) {
>  	case GIC_CPU_CTRL:
> -		mask = GICH_VMCR_CTRL_MASK;
> -		shift = GICH_VMCR_CTRL_SHIFT;
> +		vmcr_field = &vmcr.ctlr;
>  		break;
>  	case GIC_CPU_PRIMASK:
> -		mask = GICH_VMCR_PRIMASK_MASK;
> -		shift = GICH_VMCR_PRIMASK_SHIFT;
> +		vmcr_field = &vmcr.pmr;
>  		break;
>  	case GIC_CPU_BINPOINT:
> -		mask = GICH_VMCR_BINPOINT_MASK;
> -		shift = GICH_VMCR_BINPOINT_SHIFT;
> +		vmcr_field = &vmcr.bpr;
>  		break;
>  	case GIC_CPU_ALIAS_BINPOINT:
> -		mask = GICH_VMCR_ALIAS_BINPOINT_MASK;
> -		shift = GICH_VMCR_ALIAS_BINPOINT_SHIFT;
> +		vmcr_field = &vmcr.abpr;
>  		break;
> +	default:
> +		BUG();
>  	}
>  
>  	if (!mmio->is_write) {
> -		reg = (vgic_cpu->vgic_v2.vgic_vmcr & mask) >> shift;
> +		reg = *vmcr_field;
>  		mmio_data_write(mmio, ~0, reg);
>  	} else {
>  		reg = mmio_data_read(mmio, ~0);
> -		reg = (reg << shift) & mask;
> -		if (reg != (vgic_cpu->vgic_v2.vgic_vmcr & mask))
> +		if (reg != *vmcr_field) {
> +			*vmcr_field = reg;
> +			vgic_set_vmcr(vcpu, &vmcr);
>  			updated = true;
> -		vgic_cpu->vgic_v2.vgic_vmcr &= ~mask;
> -		vgic_cpu->vgic_v2.vgic_vmcr |= reg;
> +		}
>  	}
>  	return updated;
>  }
> -- 
> 1.8.3.4
> 

I'd like to actually try and compile this patch before giving a
reviewed-by tag, but it looks good otherwise.

-Christoffer