[PATCH 09/27] RISC-V: KVM: Don't check hstateen0 when updating sstateen0 CSR

[Radim Krčmář]

2026-01-20T13:29:55+05:30, Anup Patel <anup.patel at oss.qualcomm.com>:
> The hstateen0 will be programmed differently for guest HS-mode
> and guest VS/VU-mode so don't check hstateen0.SSTATEEN0 bit when
> updating sstateen0 CSR in kvm_riscv_vcpu_swap_in_guest_state()
> and kvm_riscv_vcpu_swap_in_host_state().
>
> Signed-off-by: Anup Patel <anup.patel at oss.qualcomm.com>
> ---
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> @@ -702,28 +702,22 @@ static __always_inline void kvm_riscv_vcpu_swap_in_guest_state(struct kvm_vcpu *
> -	if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SMSTATEEN) &&
> -	    (cfg->hstateen0 & SMSTATEEN0_SSTATEEN0))
> -		vcpu->arch.host_sstateen0 = csr_swap(CSR_SSTATEEN0,
> -						     smcsr->sstateen0);
> +	if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SMSTATEEN))
> +		vcpu->arch.host_sstateen0 = csr_swap(CSR_SSTATEEN0, smcsr->sstateen0);

This could even be considered as a fix, although there is no bug at the
moment (both host and guest sstateen are always 0).
In the future, execution of a guest might have been tampering with the
host sstateen, because sstateen is active even when hstateen.SE0=0.

Reviewed-by: Radim Krčmář <radim.krcmar at oss.qualcomm.com>