[PATCH 5/5] KVM: RISC-V: reset smstateen CSRs

From: Radim Krčmář
Date: Thu Apr 03 2025 - 07:34:06 EST


Not resetting smstateen is a potential security hole, because VU might
be able to access state that VS does not properly context-switch.

Fixes: 81f0f314fec9 ("RISCV: KVM: Add sstateen0 context save/restore")
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxxxxxxxx>
---
arch/riscv/kvm/vcpu.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 4578863a39e3..ac0fa50bc489 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -65,6 +65,7 @@ static void kvm_riscv_vcpu_context_reset(struct kvm_vcpu *vcpu)

memset(cntx, 0, sizeof(*cntx));
memset(csr, 0, sizeof(*csr));
+ memset(&vcpu->arch.smstateen_csr, 0, sizeof(vcpu->arch.smstateen_csr));

/* Restore datap as it's not a part of the guest context. */
cntx->vector.datap = vector_datap;
--
2.48.1