[PATCH 01/13] RISC-V: KVM: Fix the size parameter check in SBI SFENCE calls

Anup Patel apatel at ventanamicro.com
Wed Jun 4 23:14:46 PDT 2025


As-per the SBI specification, an SBI remote fence operation applies
to the entire address space if either:
1) start_addr and size are both 0
2) size is equal to 2^XLEN-1

>From the above, only #1 is checked by SBI SFENCE calls so fix the
size parameter check in SBI SFENCE calls to cover #2 as well.

Fixes: 13acfec2dbcc ("RISC-V: KVM: Add remote HFENCE functions based on VCPU requests")
Signed-off-by: Anup Patel <apatel at ventanamicro.com>
---
 arch/riscv/kvm/vcpu_sbi_replace.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/kvm/vcpu_sbi_replace.c b/arch/riscv/kvm/vcpu_sbi_replace.c
index 5fbf3f94f1e8..9752d2ffff68 100644
--- a/arch/riscv/kvm/vcpu_sbi_replace.c
+++ b/arch/riscv/kvm/vcpu_sbi_replace.c
@@ -103,7 +103,7 @@ static int kvm_sbi_ext_rfence_handler(struct kvm_vcpu *vcpu, struct kvm_run *run
 		kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_FENCE_I_SENT);
 		break;
 	case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA:
-		if (cp->a2 == 0 && cp->a3 == 0)
+		if ((cp->a2 == 0 && cp->a3 == 0) || cp->a3 == -1UL)
 			kvm_riscv_hfence_vvma_all(vcpu->kvm, hbase, hmask);
 		else
 			kvm_riscv_hfence_vvma_gva(vcpu->kvm, hbase, hmask,
@@ -111,7 +111,7 @@ static int kvm_sbi_ext_rfence_handler(struct kvm_vcpu *vcpu, struct kvm_run *run
 		kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_HFENCE_VVMA_SENT);
 		break;
 	case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID:
-		if (cp->a2 == 0 && cp->a3 == 0)
+		if ((cp->a2 == 0 && cp->a3 == 0) || cp->a3 == -1UL)
 			kvm_riscv_hfence_vvma_asid_all(vcpu->kvm,
 						       hbase, hmask, cp->a4);
 		else
-- 
2.43.0




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