[PATCH v6 24/24] KVM: arm64: vgic-v3: KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES

[christoffer.dall@linaro.org (Christoffer Dall)]

On Thu, May 04, 2017 at 01:44:44PM +0200, Eric Auger wrote:
> This patch adds a new attribute to GICV3 KVM device
> KVM_DEV_ARM_VGIC_GRP_CTRL group. This allows userspace to
> flush all GICR pending tables into guest RAM.
> 
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> 
> ---
> v5 -> v6:
> - fix stored
> - GICR_PEND/PROPBASER_ADDRESS were already introduced
> 
> v4 -> v5:
> - move pending table save code/ctrl into VGICv3 instead of ITS
> - remove useless gpa_t cast
> - use the same optimization as in its_sync_lpi_pending_table
> 
> v3 -> v4:
> - remove the wrong comment about locking
> - pass kvm struct instead of its handle
> - add comment about restore method
> - remove GITR_PENDABASER.PTZ check
> - continue if target_vcpu == NULL
> - new locking strategy
> 
> v1 -> v2:
> - do not care about the 1st KB which should be zeroed according to
>   the spec.
> ---
>  arch/arm/include/uapi/asm/kvm.h     |  1 +
>  arch/arm64/include/uapi/asm/kvm.h   |  1 +
>  include/linux/irqchip/arm-gic-v3.h  |  1 +
>  virt/kvm/arm/vgic/vgic-kvm-device.c | 20 +++++++++++++++
>  virt/kvm/arm/vgic/vgic-v3.c         | 51 +++++++++++++++++++++++++++++++++++++
>  virt/kvm/arm/vgic/vgic.h            |  1 +
>  6 files changed, 75 insertions(+)
> 
> diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
> index 8e6563c..78fe803 100644
> --- a/arch/arm/include/uapi/asm/kvm.h
> +++ b/arch/arm/include/uapi/asm/kvm.h
> @@ -202,6 +202,7 @@ struct kvm_arch_memory_slot {
>  #define   KVM_DEV_ARM_VGIC_CTRL_INIT		0
>  #define   KVM_DEV_ARM_ITS_SAVE_TABLES		1
>  #define   KVM_DEV_ARM_ITS_RESTORE_TABLES	2
> +#define   KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES	3
>  
>  /* KVM_IRQ_LINE irq field index values */
>  #define KVM_ARM_IRQ_TYPE_SHIFT		24
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index 1e35115..8a3758a 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -222,6 +222,7 @@ struct kvm_arch_memory_slot {
>  #define   KVM_DEV_ARM_VGIC_CTRL_INIT		0
>  #define   KVM_DEV_ARM_ITS_SAVE_TABLES           1
>  #define   KVM_DEV_ARM_ITS_RESTORE_TABLES        2
> +#define   KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES	3
>  
>  /* Device Control API on vcpu fd */
>  #define KVM_ARM_VCPU_PMU_V3_CTRL	0
> diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
> index e09e5d7..347d26f 100644
> --- a/include/linux/irqchip/arm-gic-v3.h
> +++ b/include/linux/irqchip/arm-gic-v3.h
> @@ -186,6 +186,7 @@
>  #define GICR_PENDBASER_RaWaWb	GIC_BASER_CACHEABILITY(GICR_PENDBASER, INNER, RaWaWb)
>  
>  #define GICR_PENDBASER_PTZ				BIT_ULL(62)
> +#define GICR_PENDBASER_ADDRESS(x)    ((x) & GENMASK_ULL(51, 16))
>  
>  /*
>   * Re-Distributor registers, offsets from SGI_base
> diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
> index 859bfa8..d48743c 100644
> --- a/virt/kvm/arm/vgic/vgic-kvm-device.c
> +++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
> @@ -580,6 +580,24 @@ static int vgic_v3_set_attr(struct kvm_device *dev,
>  		reg = tmp32;
>  		return vgic_v3_attr_regs_access(dev, attr, &reg, true);
>  	}
> +	case KVM_DEV_ARM_VGIC_GRP_CTRL: {
> +		int ret;
> +
> +		switch (attr->attr) {
> +		case KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES:
> +			mutex_lock(&dev->kvm->lock);
> +
> +			if (!lock_all_vcpus(dev->kvm)) {
> +				mutex_unlock(&dev->kvm->lock);
> +				return -EBUSY;
> +			}
> +			ret = vgic_v3_save_pending_tables(dev->kvm);
> +			unlock_all_vcpus(dev->kvm);
> +			mutex_unlock(&dev->kvm->lock);
> +			return ret;
> +		}
> +		break;
> +	}
>  	}
>  	return -ENXIO;
>  }
> @@ -658,6 +676,8 @@ static int vgic_v3_has_attr(struct kvm_device *dev,
>  		switch (attr->attr) {
>  		case KVM_DEV_ARM_VGIC_CTRL_INIT:
>  			return 0;
> +		case KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES:
> +			return 0;
>  		}
>  	}
>  	return -ENXIO;
> diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
> index 0d753ae..6ff6510 100644
> --- a/virt/kvm/arm/vgic/vgic-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-v3.c
> @@ -296,6 +296,57 @@ int vgic_v3_lpi_sync_pending_status(struct kvm *kvm, struct vgic_irq *irq)
>  	return 0;
>  }
>  
> +/**
> + * vgic_its_save_pending_tables - Save the pending tables into guest RAM
> + * kvm lock and all vcpu lock must be held
> + */
> +int vgic_v3_save_pending_tables(struct kvm *kvm)
> +{
> +	struct vgic_dist *dist = &kvm->arch.vgic;
> +	int last_byte_offset = -1;
> +	struct vgic_irq *irq;
> +	int ret;
> +
> +	list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
> +		int byte_offset, bit_nr;
> +		struct kvm_vcpu *vcpu;
> +		gpa_t pendbase, ptr;
> +		bool stored;
> +		u8 val;
> +
> +		vcpu = irq->target_vcpu;
> +		if (!vcpu)
> +			continue;
> +
> +		pendbase = GICR_PENDBASER_ADDRESS(vcpu->arch.vgic_cpu.pendbaser);
> +
> +		byte_offset = irq->intid / BITS_PER_BYTE;
> +		bit_nr = irq->intid % BITS_PER_BYTE;
> +		ptr = pendbase + byte_offset;
> +
> +		if (byte_offset != last_byte_offset) {
> +			ret = kvm_read_guest(kvm, ptr, &val, 1);
> +			if (ret)
> +				return ret;
> +			last_byte_offset = byte_offset;
> +		}
> +
> +		stored = val & (1U << bit_nr);
> +		if (stored == irq->pending_latch)
> +			continue;
> +
> +		if (irq->pending_latch)
> +			val |= 1 << bit_nr;
> +		else
> +			val &= ~(1 << bit_nr);
> +
> +		ret = kvm_write_guest(kvm, ptr, &val, 1);
> +		if (ret)
> +			return ret;
> +	}
> +	return 0;
> +}
> +
>  /* check for overlapping regions and for regions crossing the end of memory */
>  static bool vgic_v3_check_base(struct kvm *kvm)
>  {
> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
> index 92a8ca0..8de59a4 100644
> --- a/virt/kvm/arm/vgic/vgic.h
> +++ b/virt/kvm/arm/vgic/vgic.h
> @@ -181,6 +181,7 @@ void vgic_v3_enable(struct kvm_vcpu *vcpu);
>  int vgic_v3_probe(const struct gic_kvm_info *info);
>  int vgic_v3_map_resources(struct kvm *kvm);
>  int vgic_v3_lpi_sync_pending_status(struct kvm *kvm, struct vgic_irq *irq);
> +int vgic_v3_save_pending_tables(struct kvm *kvm);
>  int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t dist_base_address);
>  
>  int vgic_register_its_iodevs(struct kvm *kvm);
> -- 
> 2.5.5
> 

Reviewed-by: Christoffer Dall <cdall@linaro.org>