Subject: [PATCH v4 13/19] KVM: arm/arm64: Keep GICv2 HYP VAs in kvm_vgic_global_state

From: [email-masked] (Christoffer Dall)
Date: Thu, 18 Jan 2018 15:39:49 +0100

On Thu, Jan 04, 2018 at 06:43:28PM +0000, Marc Zyngier wrote:
> As we're about to change the way we map devices at HYP, we need
> to move away from kern_hyp_va on an IO address.
> 
> One way of achieving this is to store the VAs in kvm_vgic_global_state,
> and use that directly from the HYP code. This requires a small change
> to create_hyp_io_mappings so that it can also return a HYP VA.
> 
> We take this opportunity to nuke the vctrl_base field in the emulated
> distributor, as it is not used anymore.
> 
> Signed-off-by: Marc Zyngier <[email-masked]>
> ---
>  arch/arm/include/asm/kvm_mmu.h   |  3 ++-
>  arch/arm64/include/asm/kvm_mmu.h |  3 ++-
>  include/kvm/arm_vgic.h           | 12 ++++++------
>  virt/kvm/arm/hyp/vgic-v2-sr.c    | 10 +++-------
>  virt/kvm/arm/mmu.c               | 20 ++++++++++++++++----
>  virt/kvm/arm/vgic/vgic-init.c    |  6 ------
>  virt/kvm/arm/vgic/vgic-v2.c      | 13 +++++++------
>  7 files changed, 36 insertions(+), 31 deletions(-)
> 
> diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
> index cb3bef71ec9b..feff24b34506 100644
> --- a/arch/arm/include/asm/kvm_mmu.h
> +++ b/arch/arm/include/asm/kvm_mmu.h
> @@ -42,7 +42,8 @@
>  
>  int create_hyp_mappings(void *from, void *to, pgprot_t prot);
>  int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size,
> -			   void __iomem **kaddr);
> +			   void __iomem **kaddr,
> +			   void __iomem **haddr);
>  void free_hyp_pgds(void);
>  
>  void stage2_unmap_vm(struct kvm *kvm);
> diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
> index 09a208014457..cc882e890bb1 100644
> --- a/arch/arm64/include/asm/kvm_mmu.h
> +++ b/arch/arm64/include/asm/kvm_mmu.h
> @@ -120,7 +120,8 @@ static inline unsigned long __kern_hyp_va(unsigned long v)
>  
>  int create_hyp_mappings(void *from, void *to, pgprot_t prot);
>  int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size,
> -			   void __iomem **kaddr);
> +			   void __iomem **kaddr,
> +			   void __iomem **haddr);
>  void free_hyp_pgds(void);
>  
>  void stage2_unmap_vm(struct kvm *kvm);
> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> index 8c896540a72c..8b3fbc03293b 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -57,11 +57,15 @@ struct vgic_global {
>  	/* Physical address of vgic virtual cpu interface */
>  	phys_addr_t		vcpu_base;
>  
> -	/* GICV mapping */
> +	/* GICV mapping, kernel VA */
>  	void __iomem		*vcpu_base_va;
> +	/* GICV mapping, HYP VA */
> +	void __iomem		*vcpu_hyp_va;
>  
> -	/* virtual control interface mapping */
> +	/* virtual control interface mapping, kernel VA */
>  	void __iomem		*vctrl_base;
> +	/* virtual control interface mapping, HYP VA */
> +	void __iomem		*vctrl_hyp;
>  
>  	/* Number of implemented list registers */
>  	int			nr_lr;
> @@ -198,10 +202,6 @@ struct vgic_dist {
>  
>  	int			nr_spis;
>  
> -	/* TODO: Consider moving to global state */

yay!

> -	/* Virtual control interface mapping */
> -	void __iomem		*vctrl_base;
> -
>  	/* base addresses in guest physical address space: */
>  	gpa_t			vgic_dist_base;		/* distributor */
>  	union {
> diff --git a/virt/kvm/arm/hyp/vgic-v2-sr.c b/virt/kvm/arm/hyp/vgic-v2-sr.c
> index 4573d0552af3..dbd109f3a4ab 100644
> --- a/virt/kvm/arm/hyp/vgic-v2-sr.c
> +++ b/virt/kvm/arm/hyp/vgic-v2-sr.c
> @@ -56,10 +56,8 @@ static void __hyp_text save_lrs(struct kvm_vcpu *vcpu, void __iomem *base)
>  /* vcpu is already in the HYP VA space */
>  void __hyp_text __vgic_v2_save_state(struct kvm_vcpu *vcpu)
>  {
> -	struct kvm *kvm = kern_hyp_va(vcpu->kvm);
>  	struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2;
> -	struct vgic_dist *vgic = &kvm->arch.vgic;
> -	void __iomem *base = kern_hyp_va(vgic->vctrl_base);
> +	void __iomem *base = hyp_symbol_addr(kvm_vgic_global_state)->vctrl_hyp;
>  	u64 used_lrs = vcpu->arch.vgic_cpu.used_lrs;
>  
>  	if (!base)
> @@ -81,10 +79,8 @@ void __hyp_text __vgic_v2_save_state(struct kvm_vcpu *vcpu)
>  /* vcpu is already in the HYP VA space */
>  void __hyp_text __vgic_v2_restore_state(struct kvm_vcpu *vcpu)
>  {
> -	struct kvm *kvm = kern_hyp_va(vcpu->kvm);
>  	struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2;
> -	struct vgic_dist *vgic = &kvm->arch.vgic;
> -	void __iomem *base = kern_hyp_va(vgic->vctrl_base);
> +	void __iomem *base = hyp_symbol_addr(kvm_vgic_global_state)->vctrl_hyp;
>  	int i;
>  	u64 used_lrs = vcpu->arch.vgic_cpu.used_lrs;
>  
> @@ -139,7 +135,7 @@ int __hyp_text __vgic_v2_perform_cpuif_access(struct kvm_vcpu *vcpu)
>  		return -1;
>  
>  	rd = kvm_vcpu_dabt_get_rd(vcpu);
> -	addr  = kern_hyp_va(hyp_symbol_addr(kvm_vgic_global_state)->vcpu_base_va);
> +	addr  = hyp_symbol_addr(kvm_vgic_global_state)->vcpu_hyp_va;
>  	addr += fault_ipa - vgic->vgic_cpu_base;
>  
>  	if (kvm_vcpu_dabt_iswrite(vcpu)) {
> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
> index 38adbe0a016c..6192d45d1e1a 100644
> --- a/virt/kvm/arm/mmu.c
> +++ b/virt/kvm/arm/mmu.c
> @@ -713,28 +713,40 @@ int create_hyp_mappings(void *from, void *to, pgprot_t prot)
>   * @phys_addr:	The physical start address which gets mapped
>   * @size:	Size of the region being mapped
>   * @kaddr:	Kernel VA for this mapping
> + * @haddr:	HYP VA for this mapping
>   *
> - * The resulting HYP VA is the same as the kernel VA, modulo
> - * HYP_PAGE_OFFSET.
> + * The resulting HYP VA is completely unrelated to the kernel VA.
>   */
>  int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size,
> -			   void __iomem **kaddr)
> +			   void __iomem **kaddr,
> +			   void __iomem **haddr)
>  {
>  	unsigned long start, end;
> +	int ret;
>  
>  	*kaddr = ioremap(phys_addr, size);
>  	if (!*kaddr)
>  		return -ENOMEM;
>  
>  	if (is_kernel_in_hyp_mode()) {
> +		*haddr = *kaddr;
>  		return 0;
>  	}
>  
>  
>  	start = kern_hyp_va((unsigned long)*kaddr);
>  	end = kern_hyp_va((unsigned long)*kaddr + size);
> -	return __create_hyp_mappings(hyp_pgd, start, end,
> +	ret = __create_hyp_mappings(hyp_pgd, start, end,
>  				     __phys_to_pfn(phys_addr), PAGE_HYP_DEVICE);
> +
> +	if (ret) {
> +		iounmap(*kaddr);
> +		*kaddr = NULL;
> +	} else {
> +		*haddr = (void __iomem *)start;
> +	}

potential waste-of-time nit: this could be written perhaps slightly more
elegant as:

	if (ret) {
		iounmap(*kaddr);
		*kaddr = NULL;
		return ret;
	}

	*haddr = (void __iomem *)start
	return 0;

>  }
>  
>  /**
> diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
> index 62310122ee78..3f01b5975055 100644
> --- a/virt/kvm/arm/vgic/vgic-init.c
> +++ b/virt/kvm/arm/vgic/vgic-init.c
> @@ -166,12 +166,6 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
>  	kvm->arch.vgic.in_kernel = true;
>  	kvm->arch.vgic.vgic_model = type;
>  
> -	/*
> -	 * kvm_vgic_global_state.vctrl_base is set on vgic probe (kvm_arch_init)
> -	 * it is stored in distributor struct for asm save/restore purpose
> -	 */
> -	kvm->arch.vgic.vctrl_base = kvm_vgic_global_state.vctrl_base;
> -
>  	kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
>  	kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
>  	kvm->arch.vgic.vgic_redist_base = VGIC_ADDR_UNDEF;
> diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c
> index bc49d702f9f0..f0f566e4494e 100644
> --- a/virt/kvm/arm/vgic/vgic-v2.c
> +++ b/virt/kvm/arm/vgic/vgic-v2.c
> @@ -335,7 +335,8 @@ int vgic_v2_probe(const struct gic_kvm_info *info)
>  
>  		ret = create_hyp_io_mappings(info->vcpu.start,
>  					     resource_size(&info->vcpu),
> -					     &kvm_vgic_global_state.vcpu_base_va);
> +					     &kvm_vgic_global_state.vcpu_base_va,
> +					     &kvm_vgic_global_state.vcpu_hyp_va);
>  		if (ret) {
>  			kvm_err("Cannot map GICV into hyp\n");
>  			goto out;
> @@ -346,7 +347,8 @@ int vgic_v2_probe(const struct gic_kvm_info *info)
>  
>  	ret = create_hyp_io_mappings(info->vctrl.start,
>  				     resource_size(&info->vctrl),
> -				     &kvm_vgic_global_state.vctrl_base);
> +				     &kvm_vgic_global_state.vctrl_base,
> +				     &kvm_vgic_global_state.vctrl_hyp);
>  	if (ret) {
>  		kvm_err("Cannot map VCTRL into hyp\n");
>  		goto out;
> @@ -381,15 +383,14 @@ int vgic_v2_probe(const struct gic_kvm_info *info)
>  void vgic_v2_load(struct kvm_vcpu *vcpu)
>  {
>  	struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2;
> -	struct vgic_dist *vgic = &vcpu->kvm->arch.vgic;
>  
> -	writel_relaxed(cpu_if->vgic_vmcr, vgic->vctrl_base + GICH_VMCR);
> +	writel_relaxed(cpu_if->vgic_vmcr,
> +		       kvm_vgic_global_state.vctrl_base + GICH_VMCR);
>  }
>  
>  void vgic_v2_put(struct kvm_vcpu *vcpu)
>  {
>  	struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2;
> -	struct vgic_dist *vgic = &vcpu->kvm->arch.vgic;
>  
> -	cpu_if->vgic_vmcr = readl_relaxed(vgic->vctrl_base + GICH_VMCR);
> +	cpu_if->vgic_vmcr = readl_relaxed(kvm_vgic_global_state.vctrl_base + GICH_VMCR);
>  }
> -- 
> 2.14.2
> 

Reviewed-by: Christoffer Dall <[email-masked]>