Re: [PATCH 05/13] RISC-V: KVM: Rename and move kvm_riscv_local_tlb_sanitize()

[Atish Patra <atish.patra@linux.dev>]

On 6/4/25 11:14 PM, Anup Patel wrote:
> 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>
> ---
>   arch/riscv/include/asm/kvm_host.h |  3 +--
>   arch/riscv/kvm/tlb.c              | 23 -----------------------
>   arch/riscv/kvm/vcpu.c             |  4 ++--
>   arch/riscv/kvm/vmid.c             | 23 +++++++++++++++++++++++
>   4 files changed, 26 insertions(+), 27 deletions(-)
>
> diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
> index 85cfebc32e4c..134adc30af52 100644
> --- a/arch/riscv/include/asm/kvm_host.h
> +++ b/arch/riscv/include/asm/kvm_host.h
> @@ -327,8 +327,6 @@ void kvm_riscv_local_hfence_vvma_gva(unsigned long vmid,
>   				     unsigned long order);
>   void kvm_riscv_local_hfence_vvma_all(unsigned long vmid);
>   
> -void kvm_riscv_local_tlb_sanitize(struct kvm_vcpu *vcpu);
> -
>   void kvm_riscv_fence_i_process(struct kvm_vcpu *vcpu);
>   void kvm_riscv_hfence_gvma_vmid_all_process(struct kvm_vcpu *vcpu);
>   void kvm_riscv_hfence_vvma_all_process(struct kvm_vcpu *vcpu);
> @@ -376,6 +374,7 @@ unsigned long kvm_riscv_gstage_vmid_bits(void);
>   int kvm_riscv_gstage_vmid_init(struct kvm *kvm);
>   bool kvm_riscv_gstage_vmid_ver_changed(struct kvm_vmid *vmid);
>   void kvm_riscv_gstage_vmid_update(struct kvm_vcpu *vcpu);
> +void kvm_riscv_gstage_vmid_sanitize(struct kvm_vcpu *vcpu);
>   
>   int kvm_riscv_setup_default_irq_routing(struct kvm *kvm, u32 lines);
>   
> diff --git a/arch/riscv/kvm/tlb.c b/arch/riscv/kvm/tlb.c
> index 2f91ea5f8493..b3461bfd9756 100644
> --- a/arch/riscv/kvm/tlb.c
> +++ b/arch/riscv/kvm/tlb.c
> @@ -156,29 +156,6 @@ void kvm_riscv_local_hfence_vvma_all(unsigned long vmid)
>   	csr_write(CSR_HGATP, hgatp);
>   }
>   
> -void kvm_riscv_local_tlb_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);
> -}
> -
>   void kvm_riscv_fence_i_process(struct kvm_vcpu *vcpu)
>   {
>   	kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_FENCE_I_RCVD);
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> index f98a1894d55b..cc7d00bcf345 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -961,12 +961,12 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>   		}
>   
>   		/*
> -		 * Cleanup stale TLB enteries
> +		 * Sanitize VMID mappings cached (TLB) on current CPU
>   		 *
>   		 * Note: This should be done after G-stage VMID has been
>   		 * updated using kvm_riscv_gstage_vmid_ver_changed()
>   		 */
> -		kvm_riscv_local_tlb_sanitize(vcpu);
> +		kvm_riscv_gstage_vmid_sanitize(vcpu);
>   
>   		trace_kvm_entry(vcpu);
>   
> 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);
> +}


Reviewed-by: Atish Patra <atishp@rivosinc.com>