On 18/02/2019 19:52, Dave Martin wrote:
> This patch includes the SVE register IDs in the list returned by
> KVM_GET_REG_LIST, as appropriate.
>
> On a non-SVE-enabled vcpu, no new IDs are added.
>
> On an SVE-enabled vcpu, IDs for the FPSIMD V-registers are removed
> from the list, since userspace is required to access the Z-
> registers instead to access their context. For the variably-sized
> SVE registers, the appropriate set of slice IDs are enumerated,
> depending on the maximum vector length for the vcpu.
>
> Signed-off-by: Dave Martin <[email protected]>
Reviewed-by: Julien Thierry <[email protected]>
>
> ---
>
> Changes since v4:
>
> * Drop KVM_SVE_SLICES(), which is no longer used due to the dropping of
> register multi-slice support from the series.
>
> * Drop register multi-slice support.
> ---
> arch/arm64/kvm/guest.c | 51
> ++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 51 insertions(+)
>
> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
> index 8cfa889..4a2ad60 100644
> --- a/arch/arm64/kvm/guest.c
> +++ b/arch/arm64/kvm/guest.c
> @@ -366,6 +366,14 @@ static int copy_core_reg_indices(const struct kvm_vcpu
> *vcpu,
> continue;
> }
>
> + /*
> + * The KVM_REG_ARM64_SVE regs must be used instead of
> + * KVM_REG_ARM_CORE for accessing the FPSIMD V-registers on
> + * SVE-enabled vcpus:
> + */
> + if (vcpu_has_sve(vcpu) && core_reg_offset_is_vreg(i))
> + continue;
> +
> if (uind) {
> if (put_user(reg, *uind))
> return -EFAULT;
> @@ -436,6 +444,44 @@ static int get_timer_reg(struct kvm_vcpu *vcpu, const
> struct kvm_one_reg *reg)
> return copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)) ? -EFAULT : 0;
> }
>
> +static unsigned long num_sve_regs(const struct kvm_vcpu *vcpu)
> +{
> + /* Only the first slice ever exists, for now */
> + const unsigned int slices = 1;
> +
> + if (!vcpu_has_sve(vcpu))
> + return 0;
> +
> + return slices * (SVE_NUM_PREGS + SVE_NUM_ZREGS + 1 /* FFR */);
> +}
> +
> +static int copy_sve_reg_indices(const struct kvm_vcpu *vcpu, u64 __user
> **uind)
> +{
> + /* Only the first slice ever exists, for now */
> + const unsigned int slices = 1;
> + unsigned int i, n;
> +
> + if (!vcpu_has_sve(vcpu))
> + return 0;
> +
> + for (i = 0; i < slices; i++) {
> + for (n = 0; n < SVE_NUM_ZREGS; n++) {
> + if (put_user(KVM_REG_ARM64_SVE_ZREG(n, i), (*uind)++))
> + return -EFAULT;
> + }
> +
> + for (n = 0; n < SVE_NUM_PREGS; n++) {
> + if (put_user(KVM_REG_ARM64_SVE_PREG(n, i), (*uind)++))
> + return -EFAULT;
> + }
> +
> + if (put_user(KVM_REG_ARM64_SVE_FFR(i), (*uind)++))
> + return -EFAULT;
> + }
> +
> + return 0;
> +}
> +
> /**
> * kvm_arm_num_regs - how many registers do we present via KVM_GET_ONE_REG
> *
> @@ -446,6 +492,7 @@ unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu)
> unsigned long res = 0;
>
> res += num_core_regs(vcpu);
> + res += num_sve_regs(vcpu);
> res += kvm_arm_num_sys_reg_descs(vcpu);
> res += kvm_arm_get_fw_num_regs(vcpu);
> res += NUM_TIMER_REGS;
> @@ -466,6 +513,10 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64
> __user *uindices)
> if (ret < 0)
> return ret;
>
> + ret = copy_sve_reg_indices(vcpu, &uindices);
> + if (ret)
> + return ret;
> +
> ret = kvm_arm_copy_fw_reg_indices(vcpu, uindices);
> if (ret)
> return ret;
>
--
Julien Thierry
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