Re: [PATCH v4 09/10] RISC-V: KVM: Improve vector save/restore errors

Andrew Jones
2023-08-03T17:06:04Z

On Thu, Aug 03, 2023 at 01:33:01PM -0300, Daniel Henrique Barboza wrote:
> From: Andrew Jones <ajones@ventanamicro.com>
>
> kvm_riscv_vcpu_(get/set)_reg_vector() now returns ENOENT if V is not
> available, EINVAL if reg type is not of VECTOR type, and any error that
> might be thrown by kvm_riscv_vcpu_vreg_addr().
>
> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> ---
> arch/riscv/kvm/vcpu_vector.c | 60 ++++++++++++++++++++----------------
> 1 file changed, 33 insertions(+), 27 deletions(-)
>
> diff --git a/arch/riscv/kvm/vcpu_vector.c b/arch/riscv/kvm/vcpu_vector.c
> index edd2eecbddc2..39c5bceb4d1b 100644
> --- a/arch/riscv/kvm/vcpu_vector.c
> +++ b/arch/riscv/kvm/vcpu_vector.c
> @@ -91,44 +91,44 @@ void kvm_riscv_vcpu_free_vector_context(struct kvm_vcpu *vcpu)
> }
> #endif
>
> -static void *kvm_riscv_vcpu_vreg_addr(struct kvm_vcpu *vcpu,
> +static int kvm_riscv_vcpu_vreg_addr(struct kvm_vcpu *vcpu,
> unsigned long reg_num,
> - size_t reg_size)
> + size_t reg_size,
> + void **reg_val)
> {
> struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
> - void *reg_val;
> size_t vlenb = riscv_v_vsize / 32;
>
> if (reg_num < KVM_REG_RISCV_VECTOR_REG(0)) {
> if (reg_size != sizeof(unsigned long))
> - return NULL;
> + return -EINVAL;
> switch (reg_num) {
> case KVM_REG_RISCV_VECTOR_CSR_REG(vstart):
> - reg_val = &cntx->vector.vstart;
> + *reg_val = &cntx->vector.vstart;
> break;
> case KVM_REG_RISCV_VECTOR_CSR_REG(vl):
> - reg_val = &cntx->vector.vl;
> + *reg_val = &cntx->vector.vl;
> break;
> case KVM_REG_RISCV_VECTOR_CSR_REG(vtype):
> - reg_val = &cntx->vector.vtype;
> + *reg_val = &cntx->vector.vtype;
> break;
> case KVM_REG_RISCV_VECTOR_CSR_REG(vcsr):
> - reg_val = &cntx->vector.vcsr;
> + *reg_val = &cntx->vector.vcsr;
> break;
> case KVM_REG_RISCV_VECTOR_CSR_REG(datap):
> default:
> - return NULL;
> + return -ENOENT;
> }
> } else if (reg_num <= KVM_REG_RISCV_VECTOR_REG(31)) {
> if (reg_size != vlenb)
> - return NULL;
> - reg_val = cntx->vector.datap
> + return -EINVAL;
> + *reg_val = cntx->vector.datap
> + (reg_num - KVM_REG_RISCV_VECTOR_REG(0)) * vlenb;
> } else {
> - return NULL;
> + return -ENOENT;
> }
>
> - return reg_val;
> + return 0;
> }
>
> int kvm_riscv_vcpu_get_reg_vector(struct kvm_vcpu *vcpu,
> @@ -141,17 +141,20 @@ int kvm_riscv_vcpu_get_reg_vector(struct kvm_vcpu *vcpu,
> unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
> KVM_REG_SIZE_MASK |
> rtype);
> - void *reg_val = NULL;
> size_t reg_size = KVM_REG_SIZE(reg->id);
> + void *reg_val;
> + int rc;
>
> - if (rtype == KVM_REG_RISCV_VECTOR &&
> - riscv_isa_extension_available(isa, v)) {
> - reg_val = kvm_riscv_vcpu_vreg_addr(vcpu, reg_num, reg_size);
> - }
> -
> - if (!reg_val)
> + 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);
> + if (rc)
> + return rc;
> +
> if (copy_to_user(uaddr, reg_val, reg_size))
> return -EFAULT;
>
> @@ -168,17 +171,20 @@ int kvm_riscv_vcpu_set_reg_vector(struct kvm_vcpu *vcpu,
> unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
> KVM_REG_SIZE_MASK |
> rtype);
> - void *reg_val = NULL;
> size_t reg_size = KVM_REG_SIZE(reg->id);
> + void *reg_val;
> + int rc;
>
> - if (rtype == KVM_REG_RISCV_VECTOR &&
> - riscv_isa_extension_available(isa, v)) {
> - reg_val = kvm_riscv_vcpu_vreg_addr(vcpu, reg_num, reg_size);
> - }
> -
> - if (!reg_val)
> + 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);
> + if (rc)
> + return rc;
> +
> if (copy_from_user(reg_val, uaddr, reg_size))
> return -EFAULT;

Ugh, this is totally wrong. We no longer set the register. I need to
rework this rework...