[PATCH] RISC-V: KVM: Fix build with vector support disabled

[Anup Patel]

On Tue, Sep 22, 2026 at 4:18 AM Zhanpeng Zhang
<zhangzhanpeng.jasper at bytedance.com> wrote:
>
> The kernel-mode vector context handling added unconditional calls to
> get_cpu_vector_context(), put_cpu_vector_context() and
> __kvm_riscv_vector_restore() in vcpu.c. With CONFIG_RISCV_ISA_V=n, these
> calls fail to build due to missing declarations.
>
> The get/put helpers already have no-op definitions in asm/vector.h, but
> kvm_vcpu_vector.h only includes that header when CONFIG_RISCV_ISA_V is
> enabled. Include it unconditionally and provide a no-op implementation
> of __kvm_riscv_vector_restore() for the disabled configuration, matching
> the other vector context helpers.
>
> The paths that set RISCV_V_VCPU_NEED_RESTORE are compiled out when vector
> support is disabled, so the restore stub does not discard any live
> vector state. Keep it __always_inline for its noinstr caller. The vector
> enabled implementation is unchanged.
>
> Fixes: b5060a4aa33d ("RISC-V: KVM: fix vcpu vector context handling for kernel-mode vector")
> Signed-off-by: Zhanpeng Zhang <zhangzhanpeng.jasper at bytedance.com>

LGTM.

Reviewed-by: Anup Patel <anup at brainfault.org>

Queued this patch for Linux-7.4

Thanks,
Anup


> ---
>  arch/riscv/include/asm/kvm_vcpu_vector.h | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/include/asm/kvm_vcpu_vector.h b/arch/riscv/include/asm/kvm_vcpu_vector.h
> index 6371d5ea5392..50d4789b9cac 100644
> --- a/arch/riscv/include/asm/kvm_vcpu_vector.h
> +++ b/arch/riscv/include/asm/kvm_vcpu_vector.h
> @@ -11,9 +11,9 @@
>  #define __KVM_VCPU_RISCV_VECTOR_H
>
>  #include <linux/types.h>
> +#include <asm/vector.h>
>
>  #ifdef CONFIG_RISCV_ISA_V
> -#include <asm/vector.h>
>  #include <asm/kvm_host.h>
>
>  static __always_inline void __kvm_riscv_vector_save(struct kvm_cpu_context *context)
> @@ -55,6 +55,10 @@ static inline void kvm_riscv_v_exit(void)
>
>  struct kvm_cpu_context;
>
> +static __always_inline void __kvm_riscv_vector_restore(struct kvm_cpu_context *context)
> +{
> +}
> +
>  static inline void kvm_riscv_vcpu_vector_reset(struct kvm_vcpu *vcpu)
>  {
>  }
>
> base-commit: 93f51579e7df248780214094418f205253383cc5
> --
> 2.50.1 (Apple Git-155)
>