RISC-V: KVM: Rename and move kvm_riscv_local_tlb_sanitize()

The kvm_riscv_local_tlb_sanitize() deals with sanitizing current
VMID related TLB mappings when a VCPU is moved from one host CPU
to another.

Let's move kvm_riscv_local_tlb_sanitize() to VMID management
sources and rename it to kvm_riscv_gstage_vmid_sanitize().

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Tested-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Nutty Liu <liujingqi@lanxincomputing.com>
Link: https://lore.kernel.org/r/20250618113532.471448-4-apatel@ventanamicro.com
Signed-off-by: Anup Patel <anup@brainfault.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/arch/riscv/kvm/vmid.c b/arch/riscv/kvm/vmid.c
index ddc98714ce8e..92c01255f86f 100644
--- a/arch/riscv/kvm/vmid.c
+++ b/arch/riscv/kvm/vmid.c
@@ -122,3 +122,26 @@ void kvm_riscv_gstage_vmid_update(struct kvm_vcpu *vcpu)
 	kvm_for_each_vcpu(i, v, vcpu->kvm)
 		kvm_make_request(KVM_REQ_UPDATE_HGATP, v);
 }
+
+void kvm_riscv_gstage_vmid_sanitize(struct kvm_vcpu *vcpu)
+{
+	unsigned long vmid;
+
+	if (!kvm_riscv_gstage_vmid_bits() ||
+	    vcpu->arch.last_exit_cpu == vcpu->cpu)
+		return;
+
+	/*
+	 * On RISC-V platforms with hardware VMID support, we share same
+	 * VMID for all VCPUs of a particular Guest/VM. This means we might
+	 * have stale G-stage TLB entries on the current Host CPU due to
+	 * some other VCPU of the same Guest which ran previously on the
+	 * current Host CPU.
+	 *
+	 * To cleanup stale TLB entries, we simply flush all G-stage TLB
+	 * entries by VMID whenever underlying Host CPU changes for a VCPU.
+	 */
+
+	vmid = READ_ONCE(vcpu->kvm->arch.vmid.vmid);
+	kvm_riscv_local_hfence_gvma_vmid_all(vmid);
+}