[PATCH 1/5] KVM: RISC-V: refactor vector state reset

[Anup Patel]

On Thu, Apr 3, 2025 at 5:02 PM Radim Krčmář <rkrcmar at ventanamicro.com> wrote:
>
> Do not depend on the reset structures.
>
> vector.datap is a kernel memory pointer that needs to be preserved as it
> is not a part of the guest vector data.
>
> Signed-off-by: Radim Krčmář <rkrcmar at ventanamicro.com>

Queued this patch for Linux-6.16

Thanks,
Anup

> ---
>  arch/riscv/include/asm/kvm_vcpu_vector.h |  6 ++----
>  arch/riscv/kvm/vcpu.c                    |  5 ++++-
>  arch/riscv/kvm/vcpu_vector.c             | 13 +++++++------
>  3 files changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/arch/riscv/include/asm/kvm_vcpu_vector.h b/arch/riscv/include/asm/kvm_vcpu_vector.h
> index 27f5bccdd8b0..57a798a4cb0d 100644
> --- a/arch/riscv/include/asm/kvm_vcpu_vector.h
> +++ b/arch/riscv/include/asm/kvm_vcpu_vector.h
> @@ -33,8 +33,7 @@ void kvm_riscv_vcpu_guest_vector_restore(struct kvm_cpu_context *cntx,
>                                          unsigned long *isa);
>  void kvm_riscv_vcpu_host_vector_save(struct kvm_cpu_context *cntx);
>  void kvm_riscv_vcpu_host_vector_restore(struct kvm_cpu_context *cntx);
> -int kvm_riscv_vcpu_alloc_vector_context(struct kvm_vcpu *vcpu,
> -                                       struct kvm_cpu_context *cntx);
> +int kvm_riscv_vcpu_alloc_vector_context(struct kvm_vcpu *vcpu);
>  void kvm_riscv_vcpu_free_vector_context(struct kvm_vcpu *vcpu);
>  #else
>
> @@ -62,8 +61,7 @@ static inline void kvm_riscv_vcpu_host_vector_restore(struct kvm_cpu_context *cn
>  {
>  }
>
> -static inline int kvm_riscv_vcpu_alloc_vector_context(struct kvm_vcpu *vcpu,
> -                                                     struct kvm_cpu_context *cntx)
> +static inline int kvm_riscv_vcpu_alloc_vector_context(struct kvm_vcpu *vcpu)
>  {
>         return 0;
>  }
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> index 60d684c76c58..2fb75288ecfe 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -57,6 +57,7 @@ static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu)
>         struct kvm_vcpu_csr *reset_csr = &vcpu->arch.guest_reset_csr;
>         struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
>         struct kvm_cpu_context *reset_cntx = &vcpu->arch.guest_reset_context;
> +       void *vector_datap = cntx->vector.datap;
>         bool loaded;
>
>         /**
> @@ -79,6 +80,8 @@ static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu)
>
>         kvm_riscv_vcpu_fp_reset(vcpu);
>
> +       /* Restore datap as it's not a part of the guest context. */
> +       cntx->vector.datap = vector_datap;
>         kvm_riscv_vcpu_vector_reset(vcpu);
>
>         kvm_riscv_vcpu_timer_reset(vcpu);
> @@ -143,7 +146,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
>         cntx->hstatus |= HSTATUS_SPV;
>         spin_unlock(&vcpu->arch.reset_cntx_lock);
>
> -       if (kvm_riscv_vcpu_alloc_vector_context(vcpu, cntx))
> +       if (kvm_riscv_vcpu_alloc_vector_context(vcpu))
>                 return -ENOMEM;
>
>         /* By default, make CY, TM, and IR counters accessible in VU mode */
> diff --git a/arch/riscv/kvm/vcpu_vector.c b/arch/riscv/kvm/vcpu_vector.c
> index d92d1348045c..a5f88cb717f3 100644
> --- a/arch/riscv/kvm/vcpu_vector.c
> +++ b/arch/riscv/kvm/vcpu_vector.c
> @@ -22,6 +22,9 @@ void kvm_riscv_vcpu_vector_reset(struct kvm_vcpu *vcpu)
>         struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
>
>         cntx->sstatus &= ~SR_VS;
> +
> +       cntx->vector.vlenb = riscv_v_vsize / 32;
> +
>         if (riscv_isa_extension_available(isa, v)) {
>                 cntx->sstatus |= SR_VS_INITIAL;
>                 WARN_ON(!cntx->vector.datap);
> @@ -70,13 +73,11 @@ void kvm_riscv_vcpu_host_vector_restore(struct kvm_cpu_context *cntx)
>                 __kvm_riscv_vector_restore(cntx);
>  }
>
> -int kvm_riscv_vcpu_alloc_vector_context(struct kvm_vcpu *vcpu,
> -                                       struct kvm_cpu_context *cntx)
> +int kvm_riscv_vcpu_alloc_vector_context(struct kvm_vcpu *vcpu)
>  {
> -       cntx->vector.datap = kmalloc(riscv_v_vsize, GFP_KERNEL);
> -       if (!cntx->vector.datap)
> +       vcpu->arch.guest_context.vector.datap = kzalloc(riscv_v_vsize, GFP_KERNEL);
> +       if (!vcpu->arch.guest_context.vector.datap)
>                 return -ENOMEM;
> -       cntx->vector.vlenb = riscv_v_vsize / 32;
>
>         vcpu->arch.host_context.vector.datap = kzalloc(riscv_v_vsize, GFP_KERNEL);
>         if (!vcpu->arch.host_context.vector.datap)
> @@ -87,7 +88,7 @@ int kvm_riscv_vcpu_alloc_vector_context(struct kvm_vcpu *vcpu,
>
>  void kvm_riscv_vcpu_free_vector_context(struct kvm_vcpu *vcpu)
>  {
> -       kfree(vcpu->arch.guest_reset_context.vector.datap);
> +       kfree(vcpu->arch.guest_context.vector.datap);
>         kfree(vcpu->arch.host_context.vector.datap);
>  }
>  #endif
> --
> 2.48.1
>