Re: [PATCH v4 2/5] arm/arm64: vgic-new: Add distributor and redistributor access

[Marc Zyngier <marc.zyngier@arm.com>]

On 10/09/16 13:22, vijay.kilari@gmail.com wrote:
> From: Vijaya Kumar K <Vijaya.Kumar@cavium.com>
> 
> VGICv3 Distributor and Redistributor registers are accessed using
> KVM_DEV_ARM_VGIC_GRP_DIST_REGS and KVM_DEV_ARM_VGIC_GRP_DIST_REGS
> with KVM_SET_DEVICE_ATTR and KVM_GET_DEVICE_ATTR ioctls.
> These registers are accessed as 32-bit and cpu mpidr
> value passed along with register offset is used to identify the
> cpu for redistributor registers access.
> 
> The version of VGIC v3 specification is define here
> http://lists.infradead.org/pipermail/linux-arm-kernel/2016-July/445611.html
> 
> Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@cavium.com>
> ---
>  arch/arm64/include/uapi/asm/kvm.h   |   4 ++
>  virt/kvm/arm/vgic/vgic-kvm-device.c | 140 ++++++++++++++++++++++++++++++++++--
>  virt/kvm/arm/vgic/vgic-mmio-v2.c    |  16 +----
>  virt/kvm/arm/vgic/vgic-mmio-v3.c    |  72 +++++++++++++++++++
>  virt/kvm/arm/vgic/vgic-mmio.c       |  22 ++++++
>  virt/kvm/arm/vgic/vgic-mmio.h       |   4 ++
>  virt/kvm/arm/vgic/vgic.h            |   5 ++
>  7 files changed, 245 insertions(+), 18 deletions(-)
> 
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index 3051f86..56dc08d 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -201,10 +201,14 @@ struct kvm_arch_memory_slot {
>  #define KVM_DEV_ARM_VGIC_GRP_CPU_REGS	2
>  #define   KVM_DEV_ARM_VGIC_CPUID_SHIFT	32
>  #define   KVM_DEV_ARM_VGIC_CPUID_MASK	(0xffULL << KVM_DEV_ARM_VGIC_CPUID_SHIFT)
> +#define   KVM_DEV_ARM_VGIC_V3_MPIDR_SHIFT 32
> +#define   KVM_DEV_ARM_VGIC_V3_MPIDR_MASK \
> +			(0xffffffffULL << KVM_DEV_ARM_VGIC_V3_MPIDR_SHIFT)
>  #define   KVM_DEV_ARM_VGIC_OFFSET_SHIFT	0
>  #define   KVM_DEV_ARM_VGIC_OFFSET_MASK	(0xffffffffULL << KVM_DEV_ARM_VGIC_OFFSET_SHIFT)
>  #define KVM_DEV_ARM_VGIC_GRP_NR_IRQS	3
>  #define KVM_DEV_ARM_VGIC_GRP_CTRL	4
> +#define KVM_DEV_ARM_VGIC_GRP_REDIST_REGS 5
>  #define   KVM_DEV_ARM_VGIC_CTRL_INIT	0
>  
>  /* Device Control API on vcpu fd */
> diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
> index 163b057..3225388 100644
> --- a/virt/kvm/arm/vgic/vgic-kvm-device.c
> +++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
> @@ -320,9 +320,10 @@ static int vgic_attr_regs_access_v2(struct kvm_device *dev,
>  
>  	mutex_lock(&dev->kvm->lock);
>  
> -	ret = vgic_init(dev->kvm);
> -	if (ret)
> +	if (unlikely(!vgic_initialized(dev->kvm))) {
> +		ret = -EBUSY;
>  		goto out;
> +	}
>  
>  	if (!lock_all_vcpus(dev->kvm)) {
>  		ret = -EBUSY;
> @@ -433,16 +434,144 @@ struct kvm_device_ops kvm_arm_vgic_v2_ops = {
>  
>  #ifdef CONFIG_KVM_ARM_VGIC_V3
>  
> +static int parse_vgic_v3_attr(struct kvm_device *dev,

nit: Please use a consistent naming: vgic_v3_parse_attr?

> +			      struct kvm_device_attr *attr,
> +			      struct vgic_reg_attr *reg_attr)
> +{
> +	unsigned long mpidr;
> +
> +	mpidr = (attr->attr & KVM_DEV_ARM_VGIC_V3_MPIDR_MASK) >>
> +		 KVM_DEV_ARM_VGIC_V3_MPIDR_SHIFT;
> +
> +	reg_attr->vcpu = kvm_mpidr_to_vcpu(dev->kvm, mpidr);
> +	if (!reg_attr->vcpu)
> +		return -EINVAL;
> +
> +	if (reg_attr->vcpu->vcpu_id >= atomic_read(&dev->kvm->online_vcpus))
> +		return -EINVAL;
> +
> +	reg_attr->addr = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK;
> +
> +	return 0;
> +}
> +
> +/*
> + * vgic_attr_regs_access_v3 - allows user space to access VGIC v3 state
> + *
> + * @dev:      kvm device handle
> + * @attr:     kvm device attribute
> + * @reg:      address the value is read or written
> + * @is_write: true if userspace is writing a register
> + */
> +static int vgic_attr_regs_access_v3(struct kvm_device *dev,

nit: vgic_v3_attr_access_regs? And fix the v2 version that is equally ugly?

> +				    struct kvm_device_attr *attr,
> +				    u64 *reg, bool is_write)
> +{
> +	struct vgic_reg_attr reg_attr;
> +	gpa_t addr;
> +	struct kvm_vcpu *vcpu;
> +	int ret;
> +	u32 tmp32;
> +
> +	ret = parse_vgic_v3_attr(dev, attr, &reg_attr);
> +	if (ret)
> +		return ret;
> +
> +	vcpu = reg_attr.vcpu;
> +	addr = reg_attr.addr;
> +
> +	mutex_lock(&dev->kvm->lock);
> +
> +	if (unlikely(!vgic_initialized(dev->kvm))) {
> +		ret = -EBUSY;
> +		goto out;
> +	}
> +
> +	if (!lock_all_vcpus(dev->kvm)) {
> +		ret = -EBUSY;
> +		goto out;
> +	}
> +
> +	switch (attr->group) {
> +	case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
> +		if (is_write)
> +			tmp32 = *reg;
> +
> +		ret = vgic_v3_dist_uaccess(vcpu, is_write, addr, &tmp32);
> +		if (!is_write)
> +			*reg = tmp32;
> +		break;
> +	case KVM_DEV_ARM_VGIC_GRP_REDIST_REGS:
> +		if (is_write)
> +			tmp32 = *reg;
> +
> +		ret = vgic_v3_redist_uaccess(vcpu, is_write, addr, &tmp32);
> +		if (!is_write)
> +			*reg = tmp32;
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	unlock_all_vcpus(dev->kvm);
> +out:
> +	mutex_unlock(&dev->kvm->lock);
> +	return ret;
> +}
> +
>  static int vgic_v3_set_attr(struct kvm_device *dev,
>  			    struct kvm_device_attr *attr)
>  {
> -	return vgic_set_common_attr(dev, attr);
> +	int ret;
> +
> +	ret = vgic_set_common_attr(dev, attr);
> +	if (ret != -ENXIO)
> +		return ret;
> +
> +	switch (attr->group) {
> +	case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
> +	case KVM_DEV_ARM_VGIC_GRP_REDIST_REGS: {
> +		u32 __user *uaddr = (u32 __user *)(long)attr->addr;
> +		u32 tmp32;
> +		u64 reg;
> +
> +		if (get_user(tmp32, uaddr))
> +			return -EFAULT;
> +
> +		reg = tmp32;
> +		return vgic_attr_regs_access_v3(dev, attr, &reg, true);
> +	}
> +	}
> +	return -ENXIO;
>  }
>  
>  static int vgic_v3_get_attr(struct kvm_device *dev,
>  			    struct kvm_device_attr *attr)
>  {
> -	return vgic_get_common_attr(dev, attr);
> +	int ret;
> +
> +	ret = vgic_get_common_attr(dev, attr);
> +	if (ret != -ENXIO)
> +		return ret;
> +
> +	switch (attr->group) {
> +	case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
> +	case KVM_DEV_ARM_VGIC_GRP_REDIST_REGS: {
> +		u32 __user *uaddr = (u32 __user *)(long)attr->addr;
> +		u64 reg;
> +		u32 tmp32;
> +
> +		ret = vgic_attr_regs_access_v3(dev, attr, &reg, false);
> +		if (ret)
> +			return ret;
> +		tmp32 = reg;
> +		ret = put_user(tmp32, uaddr);
> +		return ret;
> +	}
> +	}
> +
> +	return -ENXIO;
>  }
>  
>  static int vgic_v3_has_attr(struct kvm_device *dev,
> @@ -456,6 +585,9 @@ static int vgic_v3_has_attr(struct kvm_device *dev,
>  			return 0;
>  		}
>  		break;
> +	case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
> +	case KVM_DEV_ARM_VGIC_GRP_REDIST_REGS:
> +		return vgic_v3_has_attr_regs(dev, attr);
>  	case KVM_DEV_ARM_VGIC_GRP_NR_IRQS:
>  		return 0;
>  	case KVM_DEV_ARM_VGIC_GRP_CTRL:
> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
> index 0b32f40..2cb04b7 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
> @@ -368,10 +368,9 @@ unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev)
>  
>  int vgic_v2_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr)
>  {
> -	int nr_irqs = dev->kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS;
>  	const struct vgic_register_region *regions;
>  	gpa_t addr;
> -	int nr_regions, i, len;
> +	int nr_regions;
>  
>  	addr = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK;
>  
> @@ -392,18 +391,7 @@ int vgic_v2_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr)
>  	if (addr & 3)
>  		return -ENXIO;
>  
> -	for (i = 0; i < nr_regions; i++) {
> -		if (regions[i].bits_per_irq)
> -			len = (regions[i].bits_per_irq * nr_irqs) / 8;
> -		else
> -			len = regions[i].len;
> -
> -		if (regions[i].reg_offset <= addr &&
> -		    regions[i].reg_offset + len > addr)
> -			return 0;
> -	}
> -
> -	return -ENXIO;
> +	return vgic_validate_mmio_region_addr(dev, regions, nr_regions, addr);
>  }
>  
>  int vgic_v2_cpuif_uaccess(struct kvm_vcpu *vcpu, bool is_write,
> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> index 3b4d507..ffbe1ae 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> @@ -18,6 +18,8 @@
>  #include <kvm/arm_vgic.h>
>  
>  #include <asm/kvm_emulate.h>
> +#include <asm/kvm_arm.h>
> +#include <asm/kvm_mmu.h>
>  
>  #include "vgic.h"
>  #include "vgic-mmio.h"
> @@ -379,6 +381,9 @@ static const struct vgic_register_region vgic_v3_dist_registers[] = {
>  	REGISTER_DESC_WITH_LENGTH(GICD_CTLR,
>  		vgic_mmio_read_v3_misc, vgic_mmio_write_v3_misc, 16,
>  		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICD_STATUSR,
> +		vgic_mmio_read_rao, vgic_mmio_write_wi, 4,
> +		VGIC_ACCESS_32bit),
>  	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IGROUPR,
>  		vgic_mmio_read_rao, vgic_mmio_write_wi, NULL, NULL, 1,
>  		VGIC_ACCESS_32bit),
> @@ -426,12 +431,18 @@ static const struct vgic_register_region vgic_v3_rdbase_registers[] = {
>  	REGISTER_DESC_WITH_LENGTH(GICR_CTLR,
>  		vgic_mmio_read_v3r_ctlr, vgic_mmio_write_v3r_ctlr, 4,
>  		VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_STATUSR,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 4,
> +		VGIC_ACCESS_32bit),
>  	REGISTER_DESC_WITH_LENGTH(GICR_IIDR,
>  		vgic_mmio_read_v3r_iidr, vgic_mmio_write_wi, 4,
>  		VGIC_ACCESS_32bit),
>  	REGISTER_DESC_WITH_LENGTH(GICR_TYPER,
>  		vgic_mmio_read_v3r_typer, vgic_mmio_write_wi, 8,
>  		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
> +	REGISTER_DESC_WITH_LENGTH(GICR_WAKER,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 8,
> +		VGIC_ACCESS_32bit),
>  	REGISTER_DESC_WITH_LENGTH(GICR_PROPBASER,
>  		vgic_mmio_read_propbase, vgic_mmio_write_propbase, 8,
>  		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
> @@ -552,6 +563,34 @@ int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t redist_base_address)
>  	return ret;
>  }
>  
> +int vgic_v3_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr)
> +{
> +	const struct vgic_register_region *regions;
> +	gpa_t addr;
> +	int nr_regions;
> +
> +	addr = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK;
> +
> +	switch (attr->group) {
> +	case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
> +		regions = vgic_v3_dist_registers;
> +		nr_regions = ARRAY_SIZE(vgic_v3_dist_registers);
> +		break;
> +	case KVM_DEV_ARM_VGIC_GRP_REDIST_REGS:{
> +		regions = vgic_v3_rdbase_registers;
> +		nr_regions = ARRAY_SIZE(vgic_v3_rdbase_registers);
> +		break;
> +	}
> +	default:
> +		return -ENXIO;
> +	}
> +
> +	/* We only support aligned 32-bit accesses. */
> +	if (addr & 3)
> +		return -ENXIO;
> +
> +	return vgic_validate_mmio_region_addr(dev, regions, nr_regions, addr);
> +}
>  /*
>   * Compare a given affinity (level 1-3 and a level 0 mask, from the SGI
>   * generation register ICC_SGI1R_EL1) with a given VCPU.
> @@ -658,3 +697,36 @@ void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg)
>  		vgic_put_irq(vcpu->kvm, irq);
>  	}
>  }
> +
> +int vgic_v3_dist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
> +			 int offset, u32 *val)
> +{
> +	struct vgic_io_device dev = {
> +		.regions = vgic_v3_dist_registers,
> +		.nr_regions = ARRAY_SIZE(vgic_v3_dist_registers),
> +	};
> +
> +	return vgic_uaccess(vcpu, &dev, is_write, offset, val);
> +}
> +
> +int vgic_v3_redist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
> +			   int offset, u32 *val)
> +{
> +	struct vgic_io_device rd_dev = {
> +		.regions = vgic_v3_rdbase_registers,
> +		.nr_regions = ARRAY_SIZE(vgic_v3_rdbase_registers),
> +	};
> +
> +	struct vgic_io_device sgi_dev = {
> +		.regions = vgic_v3_sgibase_registers,
> +		.nr_regions = ARRAY_SIZE(vgic_v3_sgibase_registers),
> +	};
> +
> +	/* SGI_base is the next 64K frame after RD_base */
> +	if (offset >= SZ_64K)
> +		return vgic_uaccess(vcpu, &sgi_dev, is_write,
> +				    offset - SZ_64K, val);
> +	else
> +		return vgic_uaccess(vcpu, &rd_dev, is_write,
> +				    offset, val);
> +}
> diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
> index 99d88a6..9294555 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio.c
> @@ -448,6 +448,28 @@ vgic_find_mmio_region(const struct vgic_register_region *region, int nr_regions,
>  		       sizeof(region[0]), match_region);
>  }
>  
> +/* Check if address falls within the region */
> +int vgic_validate_mmio_region_addr(struct kvm_device *dev,
> +				   const struct vgic_register_region *regions,
> +				   int nr_regions, gpa_t addr)
> +{
> +	int i, len;
> +	int nr_irqs = dev->kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS;
> +
> +	for (i = 0; i < nr_regions; i++) {
> +		if (regions[i].bits_per_irq)
> +			len = (regions[i].bits_per_irq * nr_irqs) / 8;
> +		else
> +			len = regions[i].len;
> +
> +		if (regions[i].reg_offset <= addr &&
> +		    regions[i].reg_offset + len > addr)
> +			return 0;
> +	}
> +
> +	return -ENXIO;
> +}
> +
>  /*
>   * kvm_mmio_read_buf() returns a value in a format where it can be converted
>   * to a byte array and be directly observed as the guest wanted it to appear
> diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h
> index 3435f28..9a0109b 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio.h
> +++ b/virt/kvm/arm/vgic/vgic-mmio.h
> @@ -184,6 +184,10 @@ void vgic_mmio_write_config(struct kvm_vcpu *vcpu,
>  int vgic_uaccess(struct kvm_vcpu *vcpu, struct vgic_io_device *dev,
>  		 bool is_write, int offset, u32 *val);
>  
> +int vgic_validate_mmio_region_addr(struct kvm_device *dev,
> +				   const struct vgic_register_region *regions,
> +				   int nr_regions, gpa_t addr);
> +
>  unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev);
>  
>  unsigned int vgic_v3_init_dist_iodev(struct vgic_io_device *dev);
> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
> index 6c4625c..94b3479 100644
> --- a/virt/kvm/arm/vgic/vgic.h
> +++ b/virt/kvm/arm/vgic/vgic.h
> @@ -89,6 +89,11 @@ bool vgic_has_its(struct kvm *kvm);
>  int kvm_vgic_register_its_device(void);
>  void vgic_enable_lpis(struct kvm_vcpu *vcpu);
>  int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi);
> +int vgic_v3_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr);
> +int vgic_v3_dist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
> +			 int offset, u32 *val);
> +int vgic_v3_redist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
> +			 int offset, u32 *val);
>  #else
>  static inline void vgic_v3_process_maintenance(struct kvm_vcpu *vcpu)
>  {
> 

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...