[PATCH] RISC-V: KVM: Improve vector save/restore functions

Anup Patel anup at brainfault.org
Sat Aug 5 09:32:37 PDT 2023


On Fri, Aug 4, 2023 at 7:26 PM Andrew Jones <ajones at ventanamicro.com> wrote:
>
> Make two nonfunctional changes to the vector get/set vector reg
> functions and their supporting function for simplification and
> readability. The first is to not pass KVM_REG_RISCV_VECTOR, but
> rather integrate it directly into the masking. The second is to
> rename reg_val to reg_addr where and address is used instead of
> a value.
>
> Also opportunistically touch up some of the code formatting for
> a third nonfunctional change.
>
> Signed-off-by: Andrew Jones <ajones at ventanamicro.com>

Queued this patch for Linux-6.6

Thanks,
Anup

> ---
>
> This is based on "[PATCH v4 00/10] RISC-V: KVM: change get_reg/set_reg
> error code"[1]
> [1] https://lore.kernel.org/all/20230803163302.445167-1-dbarboza@ventanamicro.com/
>
>  arch/riscv/include/asm/kvm_vcpu_vector.h |  6 ++--
>  arch/riscv/kvm/vcpu_onereg.c             |  6 ++--
>  arch/riscv/kvm/vcpu_vector.c             | 46 ++++++++++--------------
>  3 files changed, 23 insertions(+), 35 deletions(-)
>
> diff --git a/arch/riscv/include/asm/kvm_vcpu_vector.h b/arch/riscv/include/asm/kvm_vcpu_vector.h
> index ff994fdd6d0d..27f5bccdd8b0 100644
> --- a/arch/riscv/include/asm/kvm_vcpu_vector.h
> +++ b/arch/riscv/include/asm/kvm_vcpu_vector.h
> @@ -74,9 +74,7 @@ static inline void kvm_riscv_vcpu_free_vector_context(struct kvm_vcpu *vcpu)
>  #endif
>
>  int kvm_riscv_vcpu_get_reg_vector(struct kvm_vcpu *vcpu,
> -                                 const struct kvm_one_reg *reg,
> -                                 unsigned long rtype);
> +                                 const struct kvm_one_reg *reg);
>  int kvm_riscv_vcpu_set_reg_vector(struct kvm_vcpu *vcpu,
> -                                 const struct kvm_one_reg *reg,
> -                                 unsigned long rtype);
> +                                 const struct kvm_one_reg *reg);
>  #endif
> diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c
> index 989ea32dbcbe..9fee1c176fbb 100644
> --- a/arch/riscv/kvm/vcpu_onereg.c
> +++ b/arch/riscv/kvm/vcpu_onereg.c
> @@ -645,8 +645,7 @@ int kvm_riscv_vcpu_set_reg(struct kvm_vcpu *vcpu,
>         case KVM_REG_RISCV_SBI_EXT:
>                 return kvm_riscv_vcpu_set_reg_sbi_ext(vcpu, reg);
>         case KVM_REG_RISCV_VECTOR:
> -               return kvm_riscv_vcpu_set_reg_vector(vcpu, reg,
> -                                                KVM_REG_RISCV_VECTOR);
> +               return kvm_riscv_vcpu_set_reg_vector(vcpu, reg);
>         default:
>                 break;
>         }
> @@ -677,8 +676,7 @@ int kvm_riscv_vcpu_get_reg(struct kvm_vcpu *vcpu,
>         case KVM_REG_RISCV_SBI_EXT:
>                 return kvm_riscv_vcpu_get_reg_sbi_ext(vcpu, reg);
>         case KVM_REG_RISCV_VECTOR:
> -               return kvm_riscv_vcpu_get_reg_vector(vcpu, reg,
> -                                                KVM_REG_RISCV_VECTOR);
> +               return kvm_riscv_vcpu_get_reg_vector(vcpu, reg);
>         default:
>                 break;
>         }
> diff --git a/arch/riscv/kvm/vcpu_vector.c b/arch/riscv/kvm/vcpu_vector.c
> index 39c5bceb4d1b..b430cbb69521 100644
> --- a/arch/riscv/kvm/vcpu_vector.c
> +++ b/arch/riscv/kvm/vcpu_vector.c
> @@ -92,9 +92,9 @@ void kvm_riscv_vcpu_free_vector_context(struct kvm_vcpu *vcpu)
>  #endif
>
>  static int kvm_riscv_vcpu_vreg_addr(struct kvm_vcpu *vcpu,
> -                                     unsigned long reg_num,
> -                                     size_t reg_size,
> -                                     void **reg_val)
> +                                   unsigned long reg_num,
> +                                   size_t reg_size,
> +                                   void **reg_addr)
>  {
>         struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
>         size_t vlenb = riscv_v_vsize / 32;
> @@ -104,16 +104,16 @@ static int kvm_riscv_vcpu_vreg_addr(struct kvm_vcpu *vcpu,
>                         return -EINVAL;
>                 switch (reg_num) {
>                 case KVM_REG_RISCV_VECTOR_CSR_REG(vstart):
> -                       *reg_val = &cntx->vector.vstart;
> +                       *reg_addr = &cntx->vector.vstart;
>                         break;
>                 case KVM_REG_RISCV_VECTOR_CSR_REG(vl):
> -                       *reg_val = &cntx->vector.vl;
> +                       *reg_addr = &cntx->vector.vl;
>                         break;
>                 case KVM_REG_RISCV_VECTOR_CSR_REG(vtype):
> -                       *reg_val = &cntx->vector.vtype;
> +                       *reg_addr = &cntx->vector.vtype;
>                         break;
>                 case KVM_REG_RISCV_VECTOR_CSR_REG(vcsr):
> -                       *reg_val = &cntx->vector.vcsr;
> +                       *reg_addr = &cntx->vector.vcsr;
>                         break;
>                 case KVM_REG_RISCV_VECTOR_CSR_REG(datap):
>                 default:
> @@ -122,8 +122,8 @@ static int kvm_riscv_vcpu_vreg_addr(struct kvm_vcpu *vcpu,
>         } else if (reg_num <= KVM_REG_RISCV_VECTOR_REG(31)) {
>                 if (reg_size != vlenb)
>                         return -EINVAL;
> -               *reg_val = cntx->vector.datap
> -                         + (reg_num - KVM_REG_RISCV_VECTOR_REG(0)) * vlenb;
> +               *reg_addr = cntx->vector.datap +
> +                           (reg_num - KVM_REG_RISCV_VECTOR_REG(0)) * vlenb;
>         } else {
>                 return -ENOENT;
>         }
> @@ -132,60 +132,52 @@ static int kvm_riscv_vcpu_vreg_addr(struct kvm_vcpu *vcpu,
>  }
>
>  int kvm_riscv_vcpu_get_reg_vector(struct kvm_vcpu *vcpu,
> -                                 const struct kvm_one_reg *reg,
> -                                 unsigned long rtype)
> +                                 const struct kvm_one_reg *reg)
>  {
>         unsigned long *isa = vcpu->arch.isa;
>         unsigned long __user *uaddr =
>                         (unsigned long __user *)(unsigned long)reg->addr;
>         unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
>                                             KVM_REG_SIZE_MASK |
> -                                           rtype);
> +                                           KVM_REG_RISCV_VECTOR);
>         size_t reg_size = KVM_REG_SIZE(reg->id);
> -       void *reg_val;
> +       void *reg_addr;
>         int rc;
>
> -       if (rtype != KVM_REG_RISCV_VECTOR)
> -               return -EINVAL;
> -
>         if (!riscv_isa_extension_available(isa, v))
>                 return -ENOENT;
>
> -       rc = kvm_riscv_vcpu_vreg_addr(vcpu, reg_num, reg_size, &reg_val);
> +       rc = kvm_riscv_vcpu_vreg_addr(vcpu, reg_num, reg_size, &reg_addr);
>         if (rc)
>                 return rc;
>
> -       if (copy_to_user(uaddr, reg_val, reg_size))
> +       if (copy_to_user(uaddr, reg_addr, reg_size))
>                 return -EFAULT;
>
>         return 0;
>  }
>
>  int kvm_riscv_vcpu_set_reg_vector(struct kvm_vcpu *vcpu,
> -                                 const struct kvm_one_reg *reg,
> -                                 unsigned long rtype)
> +                                 const struct kvm_one_reg *reg)
>  {
>         unsigned long *isa = vcpu->arch.isa;
>         unsigned long __user *uaddr =
>                         (unsigned long __user *)(unsigned long)reg->addr;
>         unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
>                                             KVM_REG_SIZE_MASK |
> -                                           rtype);
> +                                           KVM_REG_RISCV_VECTOR);
>         size_t reg_size = KVM_REG_SIZE(reg->id);
> -       void *reg_val;
> +       void *reg_addr;
>         int rc;
>
> -       if (rtype != KVM_REG_RISCV_VECTOR)
> -               return -EINVAL;
> -
>         if (!riscv_isa_extension_available(isa, v))
>                 return -ENOENT;
>
> -       rc = kvm_riscv_vcpu_vreg_addr(vcpu, reg_num, reg_size, &reg_val);
> +       rc = kvm_riscv_vcpu_vreg_addr(vcpu, reg_num, reg_size, &reg_addr);
>         if (rc)
>                 return rc;
>
> -       if (copy_from_user(reg_val, uaddr, reg_size))
> +       if (copy_from_user(reg_addr, uaddr, reg_size))
>                 return -EFAULT;
>
>         return 0;
> --
> 2.41.0
>



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