Commit 2e7be162 authored by Anup Patel's avatar Anup Patel Committed by Anup Patel
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RISC-V: KVM: Don't treat SBI HFENCE calls as NOPs 



The SBI specification clearly states that SBI HFENCE calls should
return SBI_ERR_NOT_SUPPORTED when one of the target hart doesn’t
support hypervisor extension (aka nested virtualization in-case
of KVM RISC-V).

Fixes: c7fa3c48 ("RISC-V: KVM: Treat SBI HFENCE calls as NOPs")
Reviewed-by: default avatarAtish Patra <atishp@rivosinc.com>
Signed-off-by: default avatarAnup Patel <apatel@ventanamicro.com>
Link: https://lore.kernel.org/r/20250605061458.196003-3-apatel@ventanamicro.com


Signed-off-by: default avatarAnup Patel <anup@brainfault.org>
parent 6aba0cb5

arch/riscv/kvm/vcpu_sbi_replace.c

+2 −2
Original line number Diff line number Diff line
@@ -127,9 +127,9 @@ static int kvm_sbi_ext_rfence_handler(struct kvm_vcpu *vcpu, struct kvm_run *run 
	case SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA_ASID:

		/*

		 * Until nested virtualization is implemented, the

		 * SBI HFENCE calls should be treated as NOPs

		 * SBI HFENCE calls should return not supported

		 * hence fallthrough.

		 */

		break;

	default:

		retdata->err_val = SBI_ERR_NOT_SUPPORTED;

	}